RideMonkey How To Series: Throwing a Tantrum in Public
I think I should ride it and review it since I seem to care about climbing performance more than most of you guys but I still prioritize descending ability. I also have experience with adjustable geometry and spring rate bikes since I raced a Scott Genius LT for 3 years and use travel adjust forks and ProPedal levers on all my Santa Cruzs. Here's the ride I did today on my Bronson. 5000+ft of climbing, 6000+ft of descending, competitive times on climbs, and a few KOMs on descents: https://www.strava.com/activities/643309531
If you don't wanna swing through Breckenridge with the bikes I'll at least see you at Interbike. The trails at Outdoor Demo should be perfect for the intended use because the ups and downs come too quick to want to deal with levers.
If you don't wanna swing through Breckenridge with the bikes I'll at least see you at Interbike. The trails at Outdoor Demo should be perfect for the intended use because the ups and downs come too quick to want to deal with levers.
Yes, give it to Leland.
You should have seen the guy out there today at our Enderpo race trying to hype up his Foes Mutz (dealer). "It climbs great, I ride it so far, does everything, blah blah blah". He thought i was totally nuts when I said I didn't want all that rotating mass. Yeah, the next time I saw you was when I was having a beer after the race, lol. Where was that awesome Foes during the race?
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^I rode that section of the Colorado Trail today that I did with you and I think all the hikers have erroded it so the rocks are even bigger now. Maaaad arm pump!
My last post on this topic was about defending the importance of AS and LR, and how they completely describe how a suspension system behaves under coasting and pedalling situations.
@Tantrumcycles seems to think that his suspension does something beyond what AS and LR tell us. So this post is about interpreting those AS and LR curves, and relating that to how the suspension is likely to perform, to see if that correlates with Brian's observations.
Firstly, wheel force (and its derivative, wheel rate) is what we feel as riders when cornering/pumping/jumping. It would be great if we could compare wheel force/rate graphs of different bikes to compare their performance, but the trouble is that wheel force relies on knowing all the characteristics of the spring. In the case of an air spring, there are many variables: air pressure, +ve chamber volume, -ve chamber volume, etc. All of these can be changed by the rider. This is why we tend to look at Leverage Ratio (LR) when comparing Bike A to Bike B, as LR is independent of all these variables, and makes for a more reliable comparison.
The LR of my model looks like this:
As previously noted, the starting value of this might have some error, due to measuring off a photo, and the sensitivity of the pivot locations on the ‘missing link’ and the ‘shock link’. But beyond around 20% travel the LR should align pretty well with Brian’s design value (feel free to publish that LR curve whenever you’re ready).
Enough people have commented on the LR of this bike to know that it’s not ideal, especially matched with an air shock. The very low LR right at the start has the effect of virtually eliminating any of the benefit of the –ve air chamber in the shock.
I have modelled the shock as a ‘dual chamber’ air spring, with the pressure adjusted to achieve 32% sag with 80kg rider at 65% rear weight distribution. Here’s the Wheel Force (and Rate) graph of the suspension coupled with this shock.
As you can see, the first 10mm of travel has an incredibly steep force curve, which gives a very high wheel rate. This would be noticeably harsh when the suspension extends into holes such as braking bumps. The overall wheel rate is progressive after about 25mm travel (despite the LR having a falling rate).
Mid-stroke (about 20mm to 120mm) is the zone that the rider feels when coasting/pumping/cornering/jumping. There are a lot of very experienced riders in this forum that know what they like in this zone, and they are all pretty much unanimous in their observations that a falling rate LR coupled with an air shock does not provide sufficient progression in the overall wheel rate. This insufficient progression means that rider inputs tend to get swallowed by the travel, rather than being directed through to the tyres. Some people (casual slower riders) might refer to this sensation as ‘plush’, while others (racers) call it ‘wallowy’.
End-Stroke (120-160mm).
The force at the end of stroke (1250N) is a fair bit lower than what you would see on a bike with a more linear or progressive LR curve (when modelled with the same shock – with pressure adjusted to achieve the same 32% sag with 80kg rider at 65% rear weight distribution). This suggests that the bike will be pretty easy to bottom out. However, this zone is very much dependent on the +ve chamber volume on your specific shock, so yours may ramp up more than this. This zone is also easily tuneable using volume reducers.
Anti-Squat:
For climbing, let’s look at the AS curve in 32/42 gearing. Value at sag is about 117%.
In higher gears, the AS at sag is higher. 32/36 yields about 121%, and 32/32 yields about 124%. Pedalling in these gears (or higher gears) will cause the suspension to extend.
Because the AS value is so much higher early in travel, it means that as soon as the suspension starts to extend from sag, it moves to where the AS value is even higher, and the extension force is even greater. This causes the suspension to extend all the way to top-out position when pedalling hard (such as climbing), which appears to be the very intent of this design.
The trouble with this, is that in higher gears, say 32/16, the AS value at sag is nearly 160%, so the tendency to extend under power will much greater. At the bottom of the cassette, in 32/10 gearing, the AS is 188%. This means that when pedalling hard in fast situations, e.g. DH, coming out of a fast corner, pedalling into a jump etc, the suspension will extend with a great force as you get on the gas. Most likely pitching the rider forwards and significantly upsetting the balance of the bike.
Another way of looking at AS, is to calculate the extension force that is exhibited in the rear suspension due when pedalling. I call this force ‘wheel force due to Anti-Squat’ (WFAS), and it is calculated as %AS * mha/WB.
Some of you might remember my post on this topic over three years ago, with a link to the calculations on my website (since then, Linkage software also includes this calculation on the AS graph).
The acceleration value ‘a’ is determined by how hard you’re pedalling. No pedalling means that ‘a’ would be zero, ‘maximum’ pedalling would be the acceleration required to get the front wheel to lift off the ground, in this case the maximum is around 4 ms^-2. (In Linkage software, this value is the ‘rider strength’ property, 0% being no acceleration, 100% being enough acceleration to just lift the front wheel off the ground).
If you add this ‘WF due to AS’ to the ‘WF due to spring’ then you get a ‘Total WF’ for the suspension, which accounts for the effects of Anti-Squat.
Here’s a graph of the ‘Total Wheel Force’, for different acceleration values ranging from 0% (not pedalling at all) to 100% (pedalling hard enough to just lift the front wheel off the ground). The AS values used in this calculation are with the drivetrain in 32/16 gearing.
This graph actually correlates with what the graph on the Tantrum Cycles website is trying to display. As you can see, at about 80% pedalling effort, the Wheel Force curve becomes pretty much flat in the zone between 10-50mm travel. This means under these conditions, the wheel can pretty much occupy any position in this zone without any resistance (except its movement is still damped by the shock). This is very unique behaviour, and the best way I can think to describe this is ‘floppy’.
Normally, such a flat force curve would result in huge oscillations when pedalling on smooth ground (due to body movements up and down), but I think that might not play such a role here, since the suspension is being held hard against the top-out position.
So I believe Brian when he says that the wheel can ‘instantly react’ to bumps when climbing hard, because there is no spring force resisting its movement! Whether this trait is desirable is another issue, proper ride reviews will tell.
If climbing was your #1 priority, then I think this bike is worth a look.
However, for the majority of us who enjoy descending, I think the following compromises are too great to justify the apparent climbing performance:
1. The suspension’s tendency to extend (which is amplified in higher gears) when trying to accelerate in non-climbing situations.
2. Wheel rate not progressive enough for good rider support in non-pedalling situations.
So there you have it, an analysis of the suspension behaviour using only AS and LR. There’s nothing more going on here than what AS and LR tell us. But I do have to admit that the way AS and LR are used is very novel compared to what we are used to seeing, and the resulting suspension behaviour is not immediately apparent to those comparing to more ‘normal’ looking graphs.
Brian, I’m not going to go back through the thread (here, and on other forums, and on your website) and find all the quotes, but there are plenty of occasions where you have dismissed the relevance of AS and LR, claiming that this suspension does something beyond what AS and LR describe. I disagree, and I think that the above analysis (using only AS and LR) confirms much of the behaviour that you describe.
I urge you to reconsider your opinion on the relevance of AS and LR, and hopefully you will see that they ARE very useful parameters that completely describe the suspension behaviour. If you still think that there is something more to your suspension than what AS and LR tell us, you’re going to have to present a very convincing engineering argument.
If you’re not happy with the numbers published above, then you know what you have to do to have it amended. Either way, it’s very unlikely that a small change in pivot locations is going to make any significant difference to the general shape of these graphs.
Finally, I (and others here) have gotta admire Brian’s passion and persistence. He’s been copping a fair bit of criticism from many angles, and he’s still here and posting with a relatively positive attitude.
Cheers,
Hugh.
@Tantrumcycles seems to think that his suspension does something beyond what AS and LR tell us. So this post is about interpreting those AS and LR curves, and relating that to how the suspension is likely to perform, to see if that correlates with Brian's observations.
Firstly, wheel force (and its derivative, wheel rate) is what we feel as riders when cornering/pumping/jumping. It would be great if we could compare wheel force/rate graphs of different bikes to compare their performance, but the trouble is that wheel force relies on knowing all the characteristics of the spring. In the case of an air spring, there are many variables: air pressure, +ve chamber volume, -ve chamber volume, etc. All of these can be changed by the rider. This is why we tend to look at Leverage Ratio (LR) when comparing Bike A to Bike B, as LR is independent of all these variables, and makes for a more reliable comparison.
The LR of my model looks like this:
As previously noted, the starting value of this might have some error, due to measuring off a photo, and the sensitivity of the pivot locations on the ‘missing link’ and the ‘shock link’. But beyond around 20% travel the LR should align pretty well with Brian’s design value (feel free to publish that LR curve whenever you’re ready).
Enough people have commented on the LR of this bike to know that it’s not ideal, especially matched with an air shock. The very low LR right at the start has the effect of virtually eliminating any of the benefit of the –ve air chamber in the shock.
I have modelled the shock as a ‘dual chamber’ air spring, with the pressure adjusted to achieve 32% sag with 80kg rider at 65% rear weight distribution. Here’s the Wheel Force (and Rate) graph of the suspension coupled with this shock.
As you can see, the first 10mm of travel has an incredibly steep force curve, which gives a very high wheel rate. This would be noticeably harsh when the suspension extends into holes such as braking bumps. The overall wheel rate is progressive after about 25mm travel (despite the LR having a falling rate).
Mid-stroke (about 20mm to 120mm) is the zone that the rider feels when coasting/pumping/cornering/jumping. There are a lot of very experienced riders in this forum that know what they like in this zone, and they are all pretty much unanimous in their observations that a falling rate LR coupled with an air shock does not provide sufficient progression in the overall wheel rate. This insufficient progression means that rider inputs tend to get swallowed by the travel, rather than being directed through to the tyres. Some people (casual slower riders) might refer to this sensation as ‘plush’, while others (racers) call it ‘wallowy’.
End-Stroke (120-160mm).
The force at the end of stroke (1250N) is a fair bit lower than what you would see on a bike with a more linear or progressive LR curve (when modelled with the same shock – with pressure adjusted to achieve the same 32% sag with 80kg rider at 65% rear weight distribution). This suggests that the bike will be pretty easy to bottom out. However, this zone is very much dependent on the +ve chamber volume on your specific shock, so yours may ramp up more than this. This zone is also easily tuneable using volume reducers.
Anti-Squat:
For climbing, let’s look at the AS curve in 32/42 gearing. Value at sag is about 117%.
In higher gears, the AS at sag is higher. 32/36 yields about 121%, and 32/32 yields about 124%. Pedalling in these gears (or higher gears) will cause the suspension to extend.
Because the AS value is so much higher early in travel, it means that as soon as the suspension starts to extend from sag, it moves to where the AS value is even higher, and the extension force is even greater. This causes the suspension to extend all the way to top-out position when pedalling hard (such as climbing), which appears to be the very intent of this design.
The trouble with this, is that in higher gears, say 32/16, the AS value at sag is nearly 160%, so the tendency to extend under power will much greater. At the bottom of the cassette, in 32/10 gearing, the AS is 188%. This means that when pedalling hard in fast situations, e.g. DH, coming out of a fast corner, pedalling into a jump etc, the suspension will extend with a great force as you get on the gas. Most likely pitching the rider forwards and significantly upsetting the balance of the bike.
Another way of looking at AS, is to calculate the extension force that is exhibited in the rear suspension due when pedalling. I call this force ‘wheel force due to Anti-Squat’ (WFAS), and it is calculated as %AS * mha/WB.
Some of you might remember my post on this topic over three years ago, with a link to the calculations on my website (since then, Linkage software also includes this calculation on the AS graph).
The acceleration value ‘a’ is determined by how hard you’re pedalling. No pedalling means that ‘a’ would be zero, ‘maximum’ pedalling would be the acceleration required to get the front wheel to lift off the ground, in this case the maximum is around 4 ms^-2. (In Linkage software, this value is the ‘rider strength’ property, 0% being no acceleration, 100% being enough acceleration to just lift the front wheel off the ground).
If you add this ‘WF due to AS’ to the ‘WF due to spring’ then you get a ‘Total WF’ for the suspension, which accounts for the effects of Anti-Squat.
Here’s a graph of the ‘Total Wheel Force’, for different acceleration values ranging from 0% (not pedalling at all) to 100% (pedalling hard enough to just lift the front wheel off the ground). The AS values used in this calculation are with the drivetrain in 32/16 gearing.
This graph actually correlates with what the graph on the Tantrum Cycles website is trying to display. As you can see, at about 80% pedalling effort, the Wheel Force curve becomes pretty much flat in the zone between 10-50mm travel. This means under these conditions, the wheel can pretty much occupy any position in this zone without any resistance (except its movement is still damped by the shock). This is very unique behaviour, and the best way I can think to describe this is ‘floppy’.
Normally, such a flat force curve would result in huge oscillations when pedalling on smooth ground (due to body movements up and down), but I think that might not play such a role here, since the suspension is being held hard against the top-out position.
So I believe Brian when he says that the wheel can ‘instantly react’ to bumps when climbing hard, because there is no spring force resisting its movement! Whether this trait is desirable is another issue, proper ride reviews will tell.
If climbing was your #1 priority, then I think this bike is worth a look.
However, for the majority of us who enjoy descending, I think the following compromises are too great to justify the apparent climbing performance:
1. The suspension’s tendency to extend (which is amplified in higher gears) when trying to accelerate in non-climbing situations.
2. Wheel rate not progressive enough for good rider support in non-pedalling situations.
So there you have it, an analysis of the suspension behaviour using only AS and LR. There’s nothing more going on here than what AS and LR tell us. But I do have to admit that the way AS and LR are used is very novel compared to what we are used to seeing, and the resulting suspension behaviour is not immediately apparent to those comparing to more ‘normal’ looking graphs.
Brian, I’m not going to go back through the thread (here, and on other forums, and on your website) and find all the quotes, but there are plenty of occasions where you have dismissed the relevance of AS and LR, claiming that this suspension does something beyond what AS and LR describe. I disagree, and I think that the above analysis (using only AS and LR) confirms much of the behaviour that you describe.
I urge you to reconsider your opinion on the relevance of AS and LR, and hopefully you will see that they ARE very useful parameters that completely describe the suspension behaviour. If you still think that there is something more to your suspension than what AS and LR tell us, you’re going to have to present a very convincing engineering argument.
If you’re not happy with the numbers published above, then you know what you have to do to have it amended. Either way, it’s very unlikely that a small change in pivot locations is going to make any significant difference to the general shape of these graphs.
Finally, I (and others here) have gotta admire Brian’s passion and persistence. He’s been copping a fair bit of criticism from many angles, and he’s still here and posting with a relatively positive attitude.
Cheers,
Hugh.
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Big props for that explanation. I think it really shows why most of us here are not very positive about the planned "advantages" of the design and I also think it shows why would RC like it since he always was a fan of sacrificing suspension performance over pedaling (plus he always liked those wacky santa cruz LR curves. This seems like an exaggerated VP-Free in terms of leverage curve)My last post on this topic was about defending the importance of AS and LR, and how they completely describe how a suspension system behaves under coasting and pedalling situations.
@Tantrumcycles seems to think that his suspension does something beyond what AS and LR tell us. So this post is about interpreting those AS and LR curves, and relating that to how the suspension is likely to perform, to see if that correlates with Brian's observations.
Firstly, wheel force (and its derivative, wheel rate) is what we feel as riders when cornering/pumping/jumping. It would be great if we could compare wheel force/rate graphs of different bikes to compare their performance, but the trouble is that wheel force relies on knowing all the characteristics of the spring. In the case of an air spring, there are many variables: air pressure, +ve chamber volume, -ve chamber volume, etc. All of these can be changed by the rider. This is why we tend to look at Leverage Ratio (LR) when comparing Bike A to Bike B, as LR is independent of all these variables, and makes for a more reliable comparison.
The LR of my model looks like this:
View attachment 122883
As previously noted, the starting value of this might have some error, due to measuring off a photo, and the sensitivity of the pivot locations on the ‘missing link’ and the ‘shock link’. But beyond around 20% travel the LR should align pretty well with Brian’s design value (feel free to publish that LR curve whenever you’re ready).
Enough people have commented on the LR of this bike to know that it’s not ideal, especially matched with an air shock. The very low LR right at the start has the effect of virtually eliminating any of the benefit of the –ve air chamber in the shock.
I have modelled the shock as a ‘dual chamber’ air spring, with the pressure adjusted to achieve 32% sag with 80kg rider at 65% rear weight distribution. Here’s the Wheel Force (and Rate) graph of the suspension coupled with this shock.
View attachment 122885
As you can see, the first 10mm of travel has an incredibly steep force curve, which gives a very high wheel rate. This would be noticeably harsh when the suspension extends into holes such as braking bumps. The overall wheel rate is progressive after about 25mm travel (despite the LR having a falling rate).
Mid-stroke (about 20mm to 120mm) is the zone that the rider feels when coasting/pumping/cornering/jumping. There are a lot of very experienced riders in this forum that know what they like in this zone, and they are all pretty much unanimous in their observations that a falling rate LR coupled with an air shock does not provide sufficient progression in the overall wheel rate. This insufficient progression means that rider inputs tend to get swallowed by the travel, rather than being directed through to the tyres. Some people (casual slower riders) might refer to this sensation as ‘plush’, while others (racers) call it ‘wallowy’.
End-Stroke (120-160mm).
The force at the end of stroke (1250N) is a fair bit lower than what you would see on a bike with a more linear or progressive LR curve (when modelled with the same shock – with pressure adjusted to achieve the same 32% sag with 80kg rider at 65% rear weight distribution). This suggests that the bike will be pretty easy to bottom out. However, this zone is very much dependent on the +ve chamber volume on your specific shock, so yours may ramp up more than this. This zone is also easily tuneable using volume reducers.
Anti-Squat:
View attachment 122886
For climbing, let’s look at the AS curve in 32/42 gearing. Value at sag is about 117%.
In higher gears, the AS at sag is higher. 32/36 yields about 121%, and 32/32 yields about 124%. Pedalling in these gears (or higher gears) will cause the suspension to extend.
Because the AS value is so much higher early in travel, it means that as soon as the suspension starts to extend from sag, it moves to where the AS value is even higher, and the extension force is even greater. This causes the suspension to extend all the way to top-out position when pedalling hard (such as climbing), which appears to be the very intent of this design.
The trouble with this, is that in higher gears, say 32/16, the AS value at sag is nearly 160%, so the tendency to extend under power will much greater. At the bottom of the cassette, in 32/10 gearing, the AS is 188%. This means that when pedalling hard in fast situations, e.g. DH, coming out of a fast corner, pedalling into a jump etc, the suspension will extend with a great force as you get on the gas. Most likely pitching the rider forwards and significantly upsetting the balance of the bike.
Another way of looking at AS, is to calculate the extension force that is exhibited in the rear suspension due when pedalling. I call this force ‘wheel force due to Anti-Squat’ (WFAS), and it is calculated as %AS * mha/WB.
Some of you might remember my post on this topic over three years ago, with a link to the calculations on my website (since then, Linkage software also includes this calculation on the AS graph).
The acceleration value ‘a’ is determined by how hard you’re pedalling. No pedalling means that ‘a’ would be zero, ‘maximum’ pedalling would be the acceleration required to get the front wheel to lift off the ground, in this case the maximum is around 4 ms^-2. (In Linkage software, this value is the ‘rider strength’ property, 0% being no acceleration, 100% being enough acceleration to just lift the front wheel off the ground).
If you add this ‘WF due to AS’ to the ‘WF due to spring’ then you get a ‘Total WF’ for the suspension, which accounts for the effects of Anti-Squat.
Here’s a graph of the ‘Total Wheel Force’, for different acceleration values ranging from 0% (not pedalling at all) to 100% (pedalling hard enough to just lift the front wheel off the ground). The AS values used in this calculation are with the drivetrain in 32/16 gearing.
View attachment 122887
This graph actually correlates with what the graph on the Tantrum Cycles website is trying to display. As you can see, at about 80% pedalling effort, the Wheel Force curve becomes pretty much flat in the zone between 10-50mm travel. This means under these conditions, the wheel can pretty much occupy any position in this zone without any resistance (except its movement is still damped by the shock). This is very unique behaviour, and the best way I can think to describe this is ‘floppy’.
Normally, such a flat force curve would result in huge oscillations when pedalling on smooth ground (due to body movements up and down), but I think that might not play such a role here, since the suspension is being held hard against the top-out position.
So I believe Brian when he says that the wheel can ‘instantly react’ to bumps when climbing hard, because there is no spring force resisting its movement! Whether this trait is desirable is another issue, proper ride reviews will tell.
If climbing was your #1 priority, then I think this bike is worth a look.
However, for the majority of us who enjoy descending, I think the following compromises are too great to justify the apparent climbing performance:
1. The suspension’s tendency to extend (which is amplified in higher gears) when trying to accelerate in non-climbing situations.
2. Wheel rate not progressive enough for good rider support in non-pedalling situations.
So there you have it, an analysis of the suspension behaviour using only AS and LR. There’s nothing more going on here than what AS and LR tell us. But I do have to admit that the way AS and LR are used is very novel compared to what we are used to seeing, and the resulting suspension behaviour is not immediately apparent to those comparing to more ‘normal’ looking graphs.
Brian, I’m not going to go back through the thread (here, and on other forums, and on your website) and find all the quotes, but there are plenty of occasions where you have dismissed the relevance of AS and LR, claiming that this suspension does something beyond what AS and LR describe. I disagree, and I think that the above analysis (using only AS and LR) confirms much of the behaviour that you describe.
I urge you to reconsider your opinion on the relevance of AS and LR, and hopefully you will see that they ARE very useful parameters that completely describe the suspension behaviour. If you still think that there is something more to your suspension than what AS and LR tell us, you’re going to have to present a very convincing engineering argument.
If you’re not happy with the numbers published above, then you know what you have to do to have it amended. Either way, it’s very unlikely that a small change in pivot locations is going to make any significant difference to the general shape of these graphs.
Finally, I (and others here) have gotta admire Brian’s passion and persistence. He’s been copping a fair bit of criticism from many angles, and he’s still here and posting with a relatively positive attitude.
Cheers,
Hugh.
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Hugh, that is a hell of an effort. But the problem is that you are putting so much effort into analyzing bad numbers. On your LR, over 70% is completely off the charts. What do I mean by that? 70% of you LR chart NEVER appears on the bike. Specifically, anything over 60 mm of travel or so. So, you have stated "beyond 20% LR should align pretty well with Brian's design value", It is actually beyond 30% that you LR curve is completely off the charts. Completely does not exist, in either values or slope of curve. The first 30% is not right, but the values do exist within the range of travel. And it is falling rate there.My last post on this topic was about defending the importance of AS and LR, and how they completely describe how a suspension system behaves under coasting and pedalling situations.
@Tantrumcycles seems to think that his suspension does something beyond what AS and LR tell us. So this post is about interpreting those AS and LR curves, and relating that to how the suspension is likely to perform, to see if that correlates with Brian's observations.
Firstly, wheel force (and its derivative, wheel rate) is what we feel as riders when cornering/pumping/jumping. It would be great if we could compare wheel force/rate graphs of different bikes to compare their performance, but the trouble is that wheel force relies on knowing all the characteristics of the spring. In the case of an air spring, there are many variables: air pressure, +ve chamber volume, -ve chamber volume, etc. All of these can be changed by the rider. This is why we tend to look at Leverage Ratio (LR) when comparing Bike A to Bike B, as LR is independent of all these variables, and makes for a more reliable comparison.
The LR of my model looks like this:
View attachment 122883
As previously noted, the starting value of this might have some error, due to measuring off a photo, and the sensitivity of the pivot locations on the ‘missing link’ and the ‘shock link’. But beyond around 20% travel the LR should align pretty well with Brian’s design value (feel free to publish that LR curve whenever you’re ready).
Enough people have commented on the LR of this bike to know that it’s not ideal, especially matched with an air shock. The very low LR right at the start has the effect of virtually eliminating any of the benefit of the –ve air chamber in the shock.
I have modelled the shock as a ‘dual chamber’ air spring, with the pressure adjusted to achieve 32% sag with 80kg rider at 65% rear weight distribution. Here’s the Wheel Force (and Rate) graph of the suspension coupled with this shock.
View attachment 122885
As you can see, the first 10mm of travel has an incredibly steep force curve, which gives a very high wheel rate. This would be noticeably harsh when the suspension extends into holes such as braking bumps. The overall wheel rate is progressive after about 25mm travel (despite the LR having a falling rate).
Mid-stroke (about 20mm to 120mm) is the zone that the rider feels when coasting/pumping/cornering/jumping. There are a lot of very experienced riders in this forum that know what they like in this zone, and they are all pretty much unanimous in their observations that a falling rate LR coupled with an air shock does not provide sufficient progression in the overall wheel rate. This insufficient progression means that rider inputs tend to get swallowed by the travel, rather than being directed through to the tyres. Some people (casual slower riders) might refer to this sensation as ‘plush’, while others (racers) call it ‘wallowy’.
End-Stroke (120-160mm).
The force at the end of stroke (1250N) is a fair bit lower than what you would see on a bike with a more linear or progressive LR curve (when modelled with the same shock – with pressure adjusted to achieve the same 32% sag with 80kg rider at 65% rear weight distribution). This suggests that the bike will be pretty easy to bottom out. However, this zone is very much dependent on the +ve chamber volume on your specific shock, so yours may ramp up more than this. This zone is also easily tuneable using volume reducers.
Anti-Squat:
View attachment 122886
For climbing, let’s look at the AS curve in 32/42 gearing. Value at sag is about 117%.
In higher gears, the AS at sag is higher. 32/36 yields about 121%, and 32/32 yields about 124%. Pedalling in these gears (or higher gears) will cause the suspension to extend.
Because the AS value is so much higher early in travel, it means that as soon as the suspension starts to extend from sag, it moves to where the AS value is even higher, and the extension force is even greater. This causes the suspension to extend all the way to top-out position when pedalling hard (such as climbing), which appears to be the very intent of this design.
The trouble with this, is that in higher gears, say 32/16, the AS value at sag is nearly 160%, so the tendency to extend under power will much greater. At the bottom of the cassette, in 32/10 gearing, the AS is 188%. This means that when pedalling hard in fast situations, e.g. DH, coming out of a fast corner, pedalling into a jump etc, the suspension will extend with a great force as you get on the gas. Most likely pitching the rider forwards and significantly upsetting the balance of the bike.
Another way of looking at AS, is to calculate the extension force that is exhibited in the rear suspension due when pedalling. I call this force ‘wheel force due to Anti-Squat’ (WFAS), and it is calculated as %AS * mha/WB.
Some of you might remember my post on this topic over three years ago, with a link to the calculations on my website (since then, Linkage software also includes this calculation on the AS graph).
The acceleration value ‘a’ is determined by how hard you’re pedalling. No pedalling means that ‘a’ would be zero, ‘maximum’ pedalling would be the acceleration required to get the front wheel to lift off the ground, in this case the maximum is around 4 ms^-2. (In Linkage software, this value is the ‘rider strength’ property, 0% being no acceleration, 100% being enough acceleration to just lift the front wheel off the ground).
If you add this ‘WF due to AS’ to the ‘WF due to spring’ then you get a ‘Total WF’ for the suspension, which accounts for the effects of Anti-Squat.
Here’s a graph of the ‘Total Wheel Force’, for different acceleration values ranging from 0% (not pedalling at all) to 100% (pedalling hard enough to just lift the front wheel off the ground). The AS values used in this calculation are with the drivetrain in 32/16 gearing.
View attachment 122887
This graph actually correlates with what the graph on the Tantrum Cycles website is trying to display. As you can see, at about 80% pedalling effort, the Wheel Force curve becomes pretty much flat in the zone between 10-50mm travel. This means under these conditions, the wheel can pretty much occupy any position in this zone without any resistance (except its movement is still damped by the shock). This is very unique behaviour, and the best way I can think to describe this is ‘floppy’.
Normally, such a flat force curve would result in huge oscillations when pedalling on smooth ground (due to body movements up and down), but I think that might not play such a role here, since the suspension is being held hard against the top-out position.
So I believe Brian when he says that the wheel can ‘instantly react’ to bumps when climbing hard, because there is no spring force resisting its movement! Whether this trait is desirable is another issue, proper ride reviews will tell.
If climbing was your #1 priority, then I think this bike is worth a look.
However, for the majority of us who enjoy descending, I think the following compromises are too great to justify the apparent climbing performance:
1. The suspension’s tendency to extend (which is amplified in higher gears) when trying to accelerate in non-climbing situations.
2. Wheel rate not progressive enough for good rider support in non-pedalling situations.
So there you have it, an analysis of the suspension behaviour using only AS and LR. There’s nothing more going on here than what AS and LR tell us. But I do have to admit that the way AS and LR are used is very novel compared to what we are used to seeing, and the resulting suspension behaviour is not immediately apparent to those comparing to more ‘normal’ looking graphs.
Brian, I’m not going to go back through the thread (here, and on other forums, and on your website) and find all the quotes, but there are plenty of occasions where you have dismissed the relevance of AS and LR, claiming that this suspension does something beyond what AS and LR describe. I disagree, and I think that the above analysis (using only AS and LR) confirms much of the behaviour that you describe.
I urge you to reconsider your opinion on the relevance of AS and LR, and hopefully you will see that they ARE very useful parameters that completely describe the suspension behaviour. If you still think that there is something more to your suspension than what AS and LR tell us, you’re going to have to present a very convincing engineering argument.
If you’re not happy with the numbers published above, then you know what you have to do to have it amended. Either way, it’s very unlikely that a small change in pivot locations is going to make any significant difference to the general shape of these graphs.
Finally, I (and others here) have gotta admire Brian’s passion and persistence. He’s been copping a fair bit of criticism from many angles, and he’s still here and posting with a relatively positive attitude.
Cheers,
Hugh.
How do you think this affects the rest of your analysis? And, you correctly stated that you do not know the air volume of the shock (much less the damping).
No, I am not going to give you the physical location of all the pivots. Or exact LR and AS curves. It's just bot gonna happen. Even if I were to post a curve here, would you even believe it?? It's so far different than what you think it is. You posted as your conclusion "it's very unlikely that a small change in pivot locations is going to make any significant difference to the general shape of these graphs". That is the BIGGEST error in your statement. Millimeters are important.
Correct me if I'm wrong, but wasn't it you, in another forum, that expressed concern that manufacturing tolerances alone would be enough to make it not work? If it wasn't, I apologize. My response was, there is a particular factory that told me they are trying to hold their shock eye to eye to within 2 mm. They will not be making my frame for that reason. so, I won't have it made there, because, I do not want the performance variation that 2 mm off would cause.
Now, you are scaling 8 pivots, not to mention all of the link lengths. You are lucky if you can scale withing +/- 2 mm for ANY of the pivots. Throw that +/-2 mm in to EVERY SINGLE PIVOT AND LINK LENGTH!!!!!!!
C'mon man ,, you're an engineer. You know that can be so far off, you should start every comment with , "I realize these numbers could be a mile off, but this is my best guess". Don't believe me?, here's the linkage challenge, go back and move every number by 2 mm, in a random direction. See what you get.
Here are some flat out errors and contradictions in your conclusion
"This means that when pedalling hard in fast situations, e.g. DH, coming out of a fast corner, pedalling into a jump etc, the suspension will extend with a great force as you get on the gas. Most likely pitching the rider forwards and significantly upsetting the balance of the bike."
This never, ever, ever happens. It can't even happen on level ground, much less DH. Why? The rider CANNOT exert enough for on level ground, to extend the rear. Standing or seated, even at the highest spike of acceleration (from a standing start). You can't do it. Nobody can. There is not enough resistance to the bike's forward movement to enable the rider to press hard enough on the pedals. In this situation, on smooth ground, it pretty much feels locked out, but at sag level.
The only time it will EVER go to full extension (beside normal suspension oscillation in bumps),, is very high effort climb. On a moderate climb, it will extend (and stay there), not not FULL extension. Why? Same reason, the rider can't push hard enough on the pedals.
I don't really want to go into the rest of your analysis at this time, it's a waste of time. Let me just say that your numbers are such that not only would I not consider designing a bike like that, I would certainly never ride one like that and if I did I'd already be dead.
I won't be through Breck before Interbike. Drop me an email please. Dirt demo will be tight, Pm's, Press, and everybody else. I'm gonna try hard to set appointments, but that gets tough when the bikes don't come back on time. At the moment, there will be 2 bikes, 160 mm x 27.5 and 125 mm x 29er. Both are a Medium frame.
My graphs were all created in excel, with very precise numbers.
Your graphs? "pivot locations won't be exact". 'but here's the funny part "close enough to draw accurate conclusions"
Nuff said
@Tantrum Cycles I kinda like Your idea. It's really cool that the bike geometry adjusts to a different situations. If I do understand the concept correctly, You have placed lower link and that small link attached to the rocker almost in line, so they create some kind of mechanical "lockout", that is controlled by the chain pull/movement of the lower link. You have designed a very low LR at the beginning of the travel, for some kind of "lockout" threshold and increased rebound damping (reduced oscillation?) . Up to ~50% of the travel suspension LR increases, then becomes kinda linear, so it can be "plush", and the bike becomes slacker as well. All that combined with very lightly valved shock (compression side only) with low air pressure to compensate for the low LR?
The problem I see with the "Missing Link" design is that for the sake of "good" pedaling efficiency, You are sacrificing the bump absorption by using a very low LR @ the beginning of the travel and, making the susp. very stiff.Every time the wheel leaves the ground, you have to go through the harsh part of the travel. It would be fine if the wheel would not leave the ground and the suspension would stay past the regressive part of the travel, but we all know - that's not gonna happen. That + an air shock (revalved or not) is a recipe for a "sub optimal suspension performance".
IMHO the Magic Link, with the "area axle path" that You have designed for Kona was a WAY better idea than this (in terms of suspension behavior).
The problem I see with the "Missing Link" design is that for the sake of "good" pedaling efficiency, You are sacrificing the bump absorption by using a very low LR @ the beginning of the travel and, making the susp. very stiff.Every time the wheel leaves the ground, you have to go through the harsh part of the travel. It would be fine if the wheel would not leave the ground and the suspension would stay past the regressive part of the travel, but we all know - that's not gonna happen. That + an air shock (revalved or not) is a recipe for a "sub optimal suspension performance".
IMHO the Magic Link, with the "area axle path" that You have designed for Kona was a WAY better idea than this (in terms of suspension behavior).
Please remove me from your email list.
Hi Troy,
It's not really a mechanical lockout. That is to say, if you take the shock out, the bike falls down. What it does do is give a very difficult transmission angle to the driven link (the upper link from the rocker), pushing down on the top of the Missing Link. Combining that with the pedaling force is what creates the "lockout" feel. But it's never really locked out. Any bump action at all immediately kicks the back of the "knee" for instant response.
You mention low air pressure. About 170psi for a 180 pound rider, up to 220-230psi for a 260 pound rider.
There seems to be a common misconception about the low LR at the beginning of the travel delivering a stiff ride. If it was that low at 30% sag, absolutely. Because there, there is already enough spring force to support your body weight. but at full extension, the spring force is very light. It just can't be stiff. When you sit on the bike, it feels very coil-like when it compresses to sag level. It's not like you feel any resistance or have to "break thru" the low LR. It just feels like a bike. Same is true riding it. When the wheel leaves the ground, the spring force is very low. It has no chance of resisting even the slightest bump or movement as soon as it touches anything.
That's one reason I focus on the wheel rate/force instead of LR. People see a low LR and think "stiff". But when the low LR occurs in a range of travel where the spring cannot even produce enough force to support the rider's weight, it just can't be stiff. The fact that it is a falling rate in that area makes it even plusher. because, yes, it was important to me. If I was going to be able to get the shock to extend, it was absolutely paramount that the travel be VERY plush in that range. Otherwise, the good climbing would only be for smooth ground.
A ratio is just a ratio. If you are starting with a very low force, the force calculated thru the ratio is still very low.
I have some more videos, including the one you mentioned, I hope today.
You are correct in your last statement, but not entirely. The Magic Link is absolutely superior for sheer bump absorption, especially square edge. Part of this is the ability for an instantaneous rearward axle path in any part of the travel (or at least the first 60-70%). The other part was the fact that the two springs would operate in series at the moment of impact, giving a softer bump response that really let the wheel get out of the way (a falling rate).
That is why, the Tantrum DH bike will be a hybrid of the two. There are things I've learned from the Missing Link that can be applied. Why not make a Magic Link bike with 160mm, like the Cadabra? Weight, expense and mechanical complexity to start with. For a DH bike, this is more forgiven. Less so for trail bikes. Plus, the Magic Link bikes can't climb as well. They DO have active geometry like the Missing Ling, just not as much.
So compared to the Magic Link, the Missing Link sacrifices some bump performance in exchange for climbing performance, simplicity, weight and expense. But it does not sacrifice bump performance compared to a conventional suspension. my claim, which is impossible to prove without riding, is that my combination of weird LR, shock valving, rising rate air spring, Missing Link rate modification to the shock, all provide a ride that is more plush over bumps.
one vid I 'm working on is blasting thru a rock garden at high speed. The wheel tracks the ground perfectly, the tire barely compresses on rock strikes (which means the suspension is, instantly) and the rider glides.
I wonder what shock setup are you using. I seem to remember you mentioned you don't "need" lots of LSC. Does that mean that you run it close to fully open? Doesn't that produce instability in berms, lips and other situations where LSC is needed when not pedaling?
I get rid of a percentage of LSC. Most of that in current shocks is at the request of mfg to keep their bike from bobbing too much under pedaling. This effects mostly small stuff. But I can run a bit more mid to high speed as well.
Not enough LSC and poor transition to HSC is one of my main gripes with OEM shocks, air shocks particularly. Climb switches and propedal switches give you that stability, at the expense of all bump absorption due to poor action. The idea that LSC should be "wide open" for descending needs to be rethought. I can't say that any mfgs put enough LSC in their shocks, and when they do, you can't use it because it just makes the shock into a jackhammer at high speed.
Starting off with the assumption that less LSC is better is a huge mistake IMO. Chassis stability is hugely important. G-outs, berms, compression, negative bumps, on all sorts of stuff the stability is greatly improved with good firm LSC.
Climb and propedal load up on LSC, which is why you lose bump absorption. Does it need to be "wide open"? Of course not. It would plummet wildly thru the stroke. Just for the fun of it, someday take all the valving out and try to ride the bike. It basically wants to slam from full extension to bottom out and back in rapid succession. It definitely illustrates the value of damping.
That's where the mid speed comes in. The oe shocks seem to be all or nothing, which is why you are complaining about the poor transition from low to hi. That's the midspeed I'm talking about. My guess is, that if you rode a shock with a good midpeed transition. you might rethink your position on LSC.
Of course, it's all semantics and we're splitting hairs without a shock dyno and chassis data acquisition.
and by this comment, " I can't say that any mfgs put enough LSC in their shocks, and when they do, you can't use it because it just makes the shock into a jackhammer at high speed.", you are pretty much saying that when they added LSC they also added mid and HSC. Otherwise it wouldn't jackhammer at high speed. Right?
No, it's not necessary to lose bump absorption at speed.
It seems you are splitting hairs more than me. You can have a lot of LSC and stability and still have great high speed bump absorption. The stability is most definitely LSC.
To have mid-speed damping, you'd have to have a mid-circuit, right?
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Yes, and it works like shit. The first thing tuners do is remove that shit.
But you are wrong, it's not shit because it's LSC. It's shit because it's propedal and a spring/air loaded valve that has to be overcome to allow movement. Remember what propedal is? It's shit because of how it's implemented, not because LSC and chassis stability are inherently bad.
You are missing my point form several posts ago. No LSC is not the enemy. The way it is implemented in current air shocks is. Propedal, for example, is the SLOWEST speed damping, where it's not needed.
I don't recall saying chassis stability is inherently bad. Some is needed. More is too much.
We've gotten a little further (finally) from the shock manufacturers that were putting crap damping circuits in air shocks, but they still exist. For some reason you get coil stuff like the DHX, RC4 and others with fairly decent circuits in them (those had some issues, I freely admit, but looking at the bigger picture...) and then with the air shocks you got absolute jokes like the RP3 and DHX air, just all screwy, like someone decided XC or non-DH riders don't really need proper damping circuits or something.
Think about most air shocks with "quick range" adjusters or climb switches. You put these things in "descend" mode and they suck compared to coil shocks. Not so much because of the spring rate, mostly because the manufacturers said F-you to all the riders and any kind of LSC support, instead thinking people want to be able to remove all stability to descend, so it will "eat the high speed bumps" better, but the stability is usually shit. Do this with most coil shocks that use more traditional valves and stacks (not crap like the RP3, CTD, DHX air, etc.) and you don't have such a huge issue, not because of the coil spring, just because they left out the dumb shit they put in the air shocks for people to "climb".
There isn't any magic going on here, most tuners will gut these dumb valves and put in traditional stuff that is valved properly, you get much better LSC support and great high speed, but the lack of good LSC support on OEM air shocks, ESPECIALLY in the "descend" mode, where you want stability, is frustrating. The shock can have this and not be a jackhammer.
This is also a big reason why these things tend to blow through travel IME.
Think about most air shocks with "quick range" adjusters or climb switches. You put these things in "descend" mode and they suck compared to coil shocks. Not so much because of the spring rate, mostly because the manufacturers said F-you to all the riders and any kind of LSC support, instead thinking people want to be able to remove all stability to descend, so it will "eat the high speed bumps" better, but the stability is usually shit. Do this with most coil shocks that use more traditional valves and stacks (not crap like the RP3, CTD, DHX air, etc.) and you don't have such a huge issue, not because of the coil spring, just because they left out the dumb shit they put in the air shocks for people to "climb".
There isn't any magic going on here, most tuners will gut these dumb valves and put in traditional stuff that is valved properly, you get much better LSC support and great high speed, but the lack of good LSC support on OEM air shocks, ESPECIALLY in the "descend" mode, where you want stability, is frustrating. The shock can have this and not be a jackhammer.
This is also a big reason why these things tend to blow through travel IME.
I'm only talking about air shocks here, by the way. because, yes, they are typically more oriented to pedaling.
And, as I think you've realized, the transition for low to high is terrible. Typically, it has too high a threshold on LSC, blows off and plunges thru the travel due to an insufficient mid speed transition. At some point, the velocity is such that the HSC maxes out, spikes. A more progressive transition from low to high slows the shaft speed down sooner, leaving less energy (and slower shaft speed) for the HSC to take care of, lessening the spike.
My contention is that they all need more mid-speed, a better transition from low to high. It would have superior bump performance, great midstroke stability and support and progress nicely into HSC for less spike.
it is likely that I will make my own shock available on my frames, for these and other reasons.
Yes. They are also more expensive, especially when considering OE cost. One of my goals with this bike is to make it more affordable. So a nice, simple, light airshock will do the job. another reason I might offer my own, they will cost me less and I can pass that on to the customer.
Once we get rid of unecessary stuff like propedal, you can put a decent valving package. It doesn't really need anything trick. There's no reason a simple shock can't deliver decent damping.
A proper shock means every customer can set it up to his needs. Everyone rides differently so one tune fits all wont work if you are after maximum performance.
Right. Not to mention, hopefully accommodating riders from 120-280 pounds or more. It's a challenge for any suspension or shock designer.
That's one reason I like air shocks. Between pressure and volume spacers, you have pretty good tuning of spring rate. Throw in a good, functional compression and rebound adjustment, with good valving and most people can find a happy setting. There's always revalving for those who must....
@Tantrum Cycles
Just a heads up - everything that @hmcleay mentioned in his post is accurate. You would be doing yourself and your bike a very functional and perceivable favour if you carefully considered everything stated in his post - particularly the negative aspects (mainly the ones regarding LR curve, AS to a lesser extent) and went back to the drawing board.
Of course to do so would require either an open mind and some faith, or a relatively good grasp of some basic engineering fundamentals to verify everything stated (which, despite the simplicity, not many companies manage - so this is by no means a direct stab at you).
Instead you've made an attempt at refuting everything he's said, which unfortuately is the least productive application of your time. Yes companies do need to blindly defend their designs from a marketing standpoint (you're not the first to do it here, believe me), but it's not going to improve your product or gain you any more buyers here. Believe it or not, to a knowledgeable user of the program, the inaccuracies in the linkage software are very small and manageable - so the effect on the conclusions drawn here are negligible. Trying to use this line of defence has failed for many manufacturers posting here in the past.
Finally, air shocks (even modern ones) have substantial nonlinearity in their spring curve behaviour. Good frames address this, but your frame wouldn't fare particularly well (in bump absorption performance) in the face of current competition even with a coil shock.
Instead of wasting your time debating what I've said here - invest it in reading post #325 without a defensive attitude and maybe you can learn something.
Best wishes, and welcome to RM.
Just a heads up - everything that @hmcleay mentioned in his post is accurate. You would be doing yourself and your bike a very functional and perceivable favour if you carefully considered everything stated in his post - particularly the negative aspects (mainly the ones regarding LR curve, AS to a lesser extent) and went back to the drawing board.
Of course to do so would require either an open mind and some faith, or a relatively good grasp of some basic engineering fundamentals to verify everything stated (which, despite the simplicity, not many companies manage - so this is by no means a direct stab at you).
Instead you've made an attempt at refuting everything he's said, which unfortuately is the least productive application of your time. Yes companies do need to blindly defend their designs from a marketing standpoint (you're not the first to do it here, believe me), but it's not going to improve your product or gain you any more buyers here. Believe it or not, to a knowledgeable user of the program, the inaccuracies in the linkage software are very small and manageable - so the effect on the conclusions drawn here are negligible. Trying to use this line of defence has failed for many manufacturers posting here in the past.
Finally, air shocks (even modern ones) have substantial nonlinearity in their spring curve behaviour. Good frames address this, but your frame wouldn't fare particularly well (in bump absorption performance) in the face of current competition even with a coil shock.
Instead of wasting your time debating what I've said here - invest it in reading post #325 without a defensive attitude and maybe you can learn something.
Best wishes, and welcome to RM.
Hi Udi, just a heads up- at least 70% of hmcleay's data was completely inaccurate. Starting with his input values, thru his curves and graphs and in his final analysis.
I have read and dissected his comments very carefully. With a very open mind. The biggest problem with it is that it does not reflect reality. Now on the 3rd iteration of actual bike, which does not exhibit the behaviour his analysis predicts.
I am curious, what response you would like . "I'm sorry, you are right. All of my thoughts are wrong and now that you point it out to me, the bike DOES NOT RIDE like I (and everyone else that rides it) thinks it does. The world is still flat, even though we just sailed around it.
The answers linkage gives are only as good as the input. Garbage in, garbage out.
With the air shock comparison, you are really losing it. The rising rate of the air spring is particularly matched to my LR. Why? Because I designed it that way. It would not be good with a linear coil spring.
ooh, I can't wait till somebody scales the patent drawings..........I will just leave it here (missing link patent application). Interesting read, especially having in mind claims made in this thread.Drawings/LR values etc.
Almost on cue, I just received a 2017 X-fusion 02 pro RCX shock to test from X-fusion. My thanks to all at X-fusion for their help.
This shock has a 4 position compression damping adjuster. No lockout, no descend mode. A shock developed by Brian Lopes. And it's MUCH better than the 2016 version.
in p1, it's too soft. much of the undesirable characteristics people are describing in the "descend" mode of competing shocks. A little too active and plungy. Not great support when loading the suspension. Maybe a little wallowy.
P2 takes that all away. The feeling of underdamped, worn out shock is gone. Still plush over small and large, just less prone to overreacting and sinking in. Good support when loaded.
P3, still good. A slightly firmer ride. More support when pumping, but maybe a little too much.
P4, too stiff everywhere. Ridable, but not optimum.
This is pretty good. At 185 pounds, I'm pretty close to the middle range of rider weight (and probably skill), so the fact that the middle two settings work is good. The leaves the lower 2 for light riders and the upper 2 for heavier riders. The CD adjuster does not invoke any pedaling platform or excessive LSC, so it doesn't become harsh in small stuff.
30% sag at about 170 psi, no bottoming. All around, pretty sweet.
@Tantrum Cycles , noone has to scale anything. Claims that You have made in this post are quite different to what You patent application says. You do specify MR values at certain points of the travel, that only confirms that @hmcleay analysis was not very far away from real values. Actually those numbers are even more ridiculous than what we thought.
Nobody has to (scale the drawings), but Somebody will. And claim ALLKNOWINGNESS from having done so.
When writing a patent, it's important to cover a wide range of interpretations of your invention. There is usually a "preferred" embodiment. There are many claims in this patent application, many of which describe completely different mechanical configurations. The "preferred embodiment", is the one you see as a finished bike.
If you have specific contradictions between my patent and my posts, please bring them up. I am not aware of any.
I mention starting a 1.7 and going to 2.7 in the range between from 1.7 to 2.7 in the range between 25% and 50% travel. These numbers indicate what is possible, and an extreme case to illustrate the potential. That's exactly why it states (in the embodiment shown), in the application.
Please not that these numbers are in the general description, not in the claims. If they were in the suspension would HAVE to be that way. I mention in the claims, the ability to manipulate the spring curves in every direction. How exactly I did the bike is a only one variation.
Before you accuse me of dodging, look up any patent with more than one claim. They all have versions that the inventor would probably never use. You try to make the claims as broad as possible, to thwart people trying to get around your patent.
For example, on the bike, the rate drop between 25% and 50% travel is about 8%. then it flattens out. The figures you mentioned in the patent are over 50% drop. Not really practical with current shock technology. But with a "smart shock", sure.