[Tantrum Cycles]

A

With all the various links on the frame and bearings between them, it looks like the load on some of the bearings could be really high, especially near top out. Like the bearing just above the shock for example. Any thoughts on that?

Also is there a frame weight somewhere? maybe I missed it, but it looks like all that hardware would add up.

Any thoughts on how the linkage of the Tantrum affects the stiffness of the bike?

1) The highest load is actually at the rocker pivot bearing. That's why it is the largest. But not near topout. Why? despite the stiff motion ratio and tough angle of transmission, there just isn't anywhere near the load at topout as there is at full compression. At any rate, sizing bearings isn't exactly rocket surgery. Bearing life has been good in the test bikes.

2) Frame weight for the 6061 sample is 3232 grans, 7 lb 2 OZ, with no shock. Size M

With the shock, it's 3512 grams, 7 lb 12 oz.

The production frames are looking 100-150 grams lighter, same tubeset, more judicious sculpting of forgings.

3) Linkage and stiffness. There are plusses and minuses. Like any bike, having 2 sets of bearings in series for the CS pivot is not in it's favor. But, it's hardly an insurmountable problem, as we've seen many bikes with that feature that are plenty stiff.

In it's favor, most of the bearings in front of the ST actually help stiffness. In the same way some designers use a swing link. They are adding more bearings, more links, but increasing stiffness in the process. For example, if the Missing Link did not tie in the CS to the top shock mount, it would not be as stiff.

is it the stiffest bike? No. Carbon is tough to beat on a weight/stiffness ratio. I could have made it stiffer, but felt it was stiff enough and did not want to add more weight.

For the record, the DT is DH stiff, the BB forging does wonders to tie in the ST and BB and the rear is quite a bit stiffer than a lot of bikes, so it's probably middle of the road in that regard.

thanks for asking actual questions

 

[Tantrum Cycles]

If I lived near you, believe it or not I would very happily ride your bike with an open mind.

You don't have to live near me. I get around. Where are you?

 

[Vrock]

 

[troy]

 

[ocelot]

BWAHAHAAHAH is that made on Working Model?

 

[csermonet]

wow this is great. I just joined this thread/conversation at post #320 and am now on #353, nice work RM.

edit: deleted my post because it just wasn't necessary. it was mean and shitty. but sheesh. this is a situation boys!

 

[Jm_]

Sorry, CE =Civil Engineers. They design things that don't move, roads, buidings, bridges, etc. In the U.S., those things fail with alarming regularity, despite engineering FACT.

Comments like this are why you have zero credibility.

 

[csermonet]

Comments like this are why you have zero credibility.

Ignorant post from an ignorant man(Tantrum's post obviously, not yours).

 

[Tantrum Cycles]

in addition to Vietnam, we're looking to give some demo rides in Brown County, IN. If interested, please drop me a line on the website.

thanks

brian

 

[csermonet]

in addition to Vietnam, we're looking to give some demo rides in Brown County, IN. If interested, please drop me a line on the website.

thanks

brian

Dude Brad, Brian, Brady, whatever your name is, do yourself a favor and just shut up. Everyone is reading this thread and laughing at you and your behavior. I'd say quit while you're ahead but you're so far behind it's not even funny. You need to do damage control my friend, just shut up and don't post in here anymore. If you're bikes are so god damned good then just shut up and let them come out and let the reviews speak for themselves. What you are doing right now in this forum is destroying you but you are too ignorant and short-sighted to see it.

 

[Westy]

Sorry, CE =Civil Engineers. They design things that don't move, roads, buidings, bridges, etc. In the U.S., those things fail with alarming regularity, despite engineering FACT.

approximations are good. Trends are good. Theory is good. All useful. We all have to start somewhere. Presenting them as FACT, In the face of reality. Kind dumb.

Civil engineers who design for static loads only make these

Your statement is a little dated.

 

[csermonet]

Tantrum, Outburst, Meltdown. There is a common theme here.

 

[Westy]

Tantrum, Outburst, Meltdown. There is a common theme here.

You just don't understand

 

[csermonet]

You just don't understand

 

[AngryMetalsmith]

 

[Harry BarnOwl]

Engineering is a bizarre mindset. I've met many people, both at their university and in the work place that were not well suited. Some realize it and go in a different direction, some don't.

My comment was based on the fast that you state you are an engineer that does not do engineering work. I will make an assumption that if you were good and you WANTED to do engineering work, you would. The logical conclusion would be either

1) you do not want to do engineering work

or

2) You cannot get hired to do engineering work

Either one points to "maybe not cut out to be an engineer"

I love all of your arguments based on your experience as a design engineer in the bike industry. From my perspective as a design engineer in an industry where people's lives are dependent on things working properly (oil and gas and recently dabbling in aerospace), the bike industry is abhorrent; there are absolutely no standards in place. And I'm not talking about wheel sizes, BB spacings or other dimensional standards; I'm talking about standards that actually qualify as to whether a piece of equipment will fail or not in its designed purpose. As an example, in oil and gas pressure control equipment we work to API (american petroleum institute) standards that dictate methods of design (calculation/analysis), environments in which the equipment should work and how the equipment must be tested in order to satisfy the requirements in order to be qualified for use.

The bike industry is so damned far removed from this that people can sell what the hell they like. All they need to do is throw lots of money at the marketing and graphic design departments, and attempt to dupe people with unsubstantiated claims of performance. No one is accountable and people lap it up because it's shiny.

This thread has made for a very amusing read, but I genuinely wish you the best of luck as it takes huge balls to not only set up a company and try and sell things, but also to so valiantly defend a product in the face of such deep technical scrutiny from so many genuinely qualified people. I highly recommend a change of tack in your approach to public relations though. As fun as it has been to read this thread I don't feel particularly inspired to buy your bike. I know they say any publicity is good publicity, but in this case I feel you would have been more successful in not getting involved.

All the best chief.

 

[Tantrum Cycles]

I love all of your arguments based on your experience as a design engineer in the bike industry. From my perspective as a design engineer in an industry where people's lives are dependent on things working properly (oil and gas and recently dabbling in aerospace), the bike industry is abhorrent; there are absolutely no standards in place. And I'm not talking about wheel sizes, BB spacings or other dimensional standards; I'm talking about standards that actually qualify as to whether a piece of equipment will fail or not in its designed purpose. As an example, in oil and gas pressure control equipment we work to API (american petroleum institute) standards that dictate methods of design (calculation/analysis), environments in which the equipment should work and how the equipment must be tested in order to satisfy the requirements in order to be qualified for use.

The bike industry is so damned far removed from this that people can sell what the hell they like. All they need to do is throw lots of money at the marketing and graphic design departments, and attempt to dupe people with unsubstantiated claims of performance. No one is accountable and people lap it up because it's shiny.

This thread has made for a very amusing read, but I genuinely wish you the best of luck as it takes huge balls to not only set up a company and try and sell things, but also to so valiantly defend a product in the face of such deep technical scrutiny from so many genuinely qualified people. I highly recommend a change of tack in your approach to public relations though. As fun as it has been to read this thread I don't feel particularly inspired to buy your bike. I know they say any publicity is good publicity, but in this case I feel you would have been more successful in not getting involved.

All the best chief.

Hi Harry,

before the bike industry, I spent 15 years a a race car designer in Group C, F1, Indy Cars, Trans-Am, etc. People's lives DID depend on my work and there were NO standards to guide us.

Yes, the bike industry has some catching up to do, but it is much better than 10 yrs ago. watch some videos of frames getting CEN tested and you'll see what I mean.

I know you have standards, and they keep getting revised over time. Why? We learn more. We learn our last assumptions were in error.

As far as defending my design from deep scrutiny from so many genuinely qualified people,...you mean lie vrocks' high IQ video posted above??? Very qualified..

obviously, the people that want to use the internet for derisive amusement are not and probably will not be my customer. Despite their attempts to obfuscate this thread, it has been overwhelmingly positive for me and Tantrum. The increase in web traffic and email response has been incredible, so thank you all on RM for helping me get the word out.

To the remainder who insist on getting their information from a bad pic and call it an analysis, feel free to carry on your rants. And please call me more names. And more funny pics and videos.

 

[Tantrum Cycles]

Civil engineers who design for static loads only make these

Your statement is a little dated.

You're kinda making my point.

 

[Sandwich]

So, aside from all the bashing, I did want to actually make a point-

I disagree that "climbs like a hardtail, descends like a DH bike" is the pinnacle of bike design. I want a suspension bike that climbs like a suspension bike and descends like a suspension bike. Climbing like a hardtail means breaking traction and no assist on technical climbs. I've bagged on about this for ages, but higher than average antisquat values pull that tire down into the dirt and help give you "bonus" traction as you go over less than smooth climbs or up gravely sections. Having less than 100% allows the tire to break traction regularly. To answer my own question from before- if the suspension is locked out like a hardtail as you go up and hit a depression, the rear wheel cannot drop and the tire will break traction. On a well-designed bike, the tire drops (thanks droop travel/sag), and maintains contact with the ground. On a bike with a well designed anti-squat curve, it still accelerates despite the drop, all the while maintaining forward traction and power output. If I wanted a lockout, I would lock out my suspension entirely! Climbing with a hardtail is actually inferior to a well designed suspension bike, in my experience.

Now, back to Brian- I didn't know you were the man behind Therapy components. Very innovative stuff over the years. I've contacted you multiple times for floating linkages for various bikes I've tried to buy. I've loved floaters in the past...until I started riding bikes without them. I think they certainly have their place, but without a floating linkage up front, too, they have the potential to upset the geometry of the bike due to fork dive. So, not debunked but not necessarily the tool that we really need. Also, as far as Fabien goes- did he have his floater set to remain neutral, or increase the compression of the rear suspension? The rumor I always heard was that he actually had it set to compress to improve the handling of the bike.

Finally, wicked cool that you worked with Audi and the 200 TransAm. Awesome car, dominant, and some great racers driving it.

 

[Tantrum Cycles]

S

I disagree that "climbs like a hardtail, descends like a DH bike" is the pinnacle of bike design. I want a suspension bike that climbs like a suspension bike and descends like a suspension bike. Climbing like a hardtail means breaking traction and no assist on technical climbs. ve

Sandwich. most of what you are saying is true. "climbing like a hard tail" in all conditions, was not and is never a goal.

More like "climbs like a steep geometry hardtail on smooth ground, while providing plush suspension action and traction when the ground gets rough. Even the term "lockout" is a misnomer. The suspension never locks out, it just feels like it under smooth pedaling conditions. If you watch the climbing video, you can see that the suspension is active when needed.

 

[Tantrum Cycles]

Now, back to Brian- I didn't know you were the man behind Therapy components. Very innovative stuff over the years. I've contacted you multiple times for floating linkages for various bikes I've tried to buy. I've loved floaters in the past...until I started riding bikes without them. I think they certainly have their place, but without a floating linkage up front, too, they have the potential to upset the geometry of the bike due to fork dive. So, not debunked but not necessarily the tool that we really need. Also, as far as Fabien goes- did he have his floater set to remain neutral, or increase the compression of the rear suspension? The rumor I always heard was that he actually had it set to compress to improve the handling of the bike.

Fabien had a unique setup. he would change stuff a LOT from race to race. He set his floater to compress as he braked before braking bumps, so he could use the rebound when he got off the brakes to jump over them. Nobody else, even on the factory team, could ride his setups, but that's why he was multi world champion.

he had some pretty unique fork and shock setups as well. And is the man behind the Canyon Strive, which is kind of a manual adjust Magic Link.

 

[Tantrum Cycles]

Finally, wicked cool that you worked with Audi and the 200 TransAm. Awesome car, dominant, and some great racers driving it.

The Audi program was awesome. Thanks. And a LOT of controversy over those cars. First saying it was stupid to try (sound familiar?), then dominating so much we ended up with a 400 pound weight penalty and a tire size reduction.

Really, it was the drivers. Walter Rohrl was so far above those guys, he said he could do 3 laps and close his eyes.

 

[Harry BarnOwl]

Hi Harry,

before the bike industry, I spent 15 years a a race car designer in Group C, F1, Indy Cars, Trans-Am, etc. People's lives DID depend on my work and there were NO standards to guide us.

Yes, the bike industry has some catching up to do, but it is much better than 10 yrs ago. watch some videos of frames getting CEN tested and you'll see what I mean.

I know you have standards, and they keep getting revised over time. Why? We learn more. We learn our last assumptions were in error.

As far as defending my design from deep scrutiny from so many genuinely qualified people,...you mean lie vrocks' high IQ video posted above??? Very qualified..

obviously, the people that want to use the internet for derisive amusement are not and probably will not be my customer. Despite their attempts to obfuscate this thread, it has been overwhelmingly positive for me and Tantrum. The increase in web traffic and email response has been incredible, so thank you all on RM for helping me get the word out.

To the remainder who insist on getting their information from a bad pic and call it an analysis, feel free to carry on your rants. And please call me more names. And more funny pics and videos.

I stand corrected on the publicity front then!

Agreed on the standards. A lot of people have lost lives in various industries (not to mention shafting the planet with the O&G industry) and standards/processes have been created as a result of it. Whilst people's lives don't so much depend on it in the bike industry, I think it really has some growing up to do.

Don't worry about the video, this is the internet and has to be taken with a pinch of salt sometimes...and it is kind of funny. Though I still stand by that there are some seriously bright heads on shoulders on this forum, and despite how forceful people can be with their arguments I don't agree with the way that you have responded to them.

 

[Tantrum Cycles]

I stand corrected on the publicity front then!

Agreed on the standards. A lot of people have lost lives in various industries (not to mention shafting the planet with the O&G industry) and standards/processes have been created as a result of it. Whilst people's lives don't so much depend on it in the bike industry, I think it really has some growing up to do.

The bike industry in regards to full suspension design is still very much in its infancy. Not too long ago, a certain pretty large brand was having a failure of rocker arms and asked me to comment. My first question was : "what was the design load". Blank stares. My second question was "what load did it fail at on the test rig". More blank stares.

It turns out that not a single rocker arm from any of the brand's models had EVER been calculated or tested. Just kinda modified from a previous design that didn't work. This kind of "design" still happens all too frequently in the bike world.

 

[Jm_]

I've bagged on about this for ages, but higher than average antisquat values pull that tire down into the dirt and help give you "bonus" traction as you go over less than smooth climbs or up gravely sections. Having less than 100% allows the tire to break traction regularly. To answer my own question from before- if the suspension is locked out like a hardtail as you go up and hit a depression, the rear wheel cannot drop and the tire will break traction. On a well-designed bike, the tire drops (thanks droop travel/sag), and maintains contact with the ground. On a bike with a well designed anti-squat curve, it still accelerates despite the drop, all the while maintaining forward traction and power output. If I wanted a lockout, I would lock out my suspension entirely! Climbing with a hardtail is actually inferior to a well designed suspension bike, in my experience.

Hmm, that's 100% different than my experience. On the high AS bikes, like my old K2, under power uphill it would easily break traction, as there was that additional resistance for the suspension to overcome, chain forces tugging the rear axle back towards the ground when climbing in the granny gear. Uphill traction was poor, but efficiency was good, if you could saw that slipping over technical features was good with all the associated extra energy or having to ride an abnormally high gear to not slip. On the extremely low AS bikes, I noticed that the rear end would compress significantly uphill in the tech, moreso than it would just coasting on the same type of bump even, this can cause you to stall out and hang up, as the suspension uses a lot of travel and pedaling gets significantly harder with a falling AS curve through the travel, but this also leads to that rationalization "I love my horst link in tech", as the over-use of travel provides a lot of traction.

On solid smooth pavement, I'd agree with your findings, especially say if we could lay down a huge amount of power, but that doesn't apply to irregular surfaces IME.

There's obviously a balance where the suspension can compress just the right amount and ride "above" or on a root or tech section without slipping, but also providing ample traction. Too much AS and it slips as additional resistance in the suspension breaks traction. Too little and you stalls as it forces you to supply significantly more pedaling force to overcome the low AS deep in the travel, not to mention the additional resistance to a square object deeper in the travel over a series of impacts. .

 

[Tantrum Cycles]

Don't worry about the video, this is the internet and has to be taken with a pinch of salt sometimes...and it is kind of funny. Though I still stand by that there are some seriously bright heads on shoulders on this forum, and despite how forceful people can be with their arguments I don't agree with the way that you have responded to them.

I'm not worried about the video, my comment was related to the fact that the video was produced by the very same qualified expert that posted the "analysis" of my suspension based on a scaled photo, which when presented, had fully 70% of the graph off the charts, meaning, 70 % of those values never happen in my design. It is based on his posting that all of the other experts are basing their conclusion. Which of course are contradicted by the actual bicycle.

I don't agree with the way I've responded in many cases. I am not now, or ever was the most patient man (could be why I ended up a racer for life). But I have resisted calling people names, even if I may have been unkind to a couple of them (and possibly their ability to engineer).

What will be fun is to revisit this in about 4-6 months or so. Production bikes will be in the hands of customers and reviewers world wide. While I am not expecting an "open minded" response from die-hard haters, some of you might begin to understand why I am so adamant that the "facts" presented here by some of the posters are pure fiction.

 

[Sandwich]

Hmm, that's 100% different than my experience. On the high AS bikes, like my old K2, under power uphill it would easily break traction, as there was that additional resistance for the suspension to overcome, chain forces tugging the rear axle back towards the ground when climbing in the granny gear. Uphill traction was poor, but efficiency was good, if you could saw that slipping over technical features was good with all the associated extra energy or having to ride an abnormally high gear to not slip. On the extremely low AS bikes, I noticed that the rear end would compress significantly uphill in the tech, moreso than it would just coasting on the same type of bump even, this can cause you to stall out and hang up, as the suspension uses a lot of travel and pedaling gets significantly harder with a falling AS curve through the travel, but this also leads to that rationalization "I love my horst link in tech", as the over-use of travel provides a lot of traction.

On solid smooth pavement, I'd agree with your findings, especially say if we could lay down a huge amount of power, but that doesn't apply to irregular surfaces IME.

There's obviously a balance where the suspension can compress just the right amount and ride "above" or on a root or tech section without slipping, but also providing ample traction. Too much AS and it slips as additional resistance in the suspension breaks traction. Too little and you stalls as it forces you to supply significantly more pedaling force to overcome the low AS deep in the travel, not to mention the additional resistance to a square object deeper in the travel over a series of impacts. .

how high are you talking about? I'm talking around 120-MAYBE 150%. A granny ring on a bike like the old K2s is going to be well over 200%. With the right value, a bump force should still be able to overcome the chain forces of the bike, allowing it to compress and react to bumps, then you can apply torque effectively on the other side.

I disagree with you on the pavement stuff, as this is where I usually feel the worst traits of high AS designs come out. On trail, unnoticeable, on pavement, I see it bobbing all the time.

 

[Tantrum Cycles]

There's obviously a balance where the suspension can compress just the right amount and ride "above" or on a root or tech section without slipping, but also providing ample traction. Too much AS and it slips as additional resistance in the suspension breaks traction. Too little and you stalls as it forces you to supply significantly more pedaling force to overcome the low AS deep in the travel, not to mention the additional resistance to a square object deeper in the travel over a series of impacts. .

Now we're getting somewhere. Some want to claim that the AS value on my bike, especially at full extension, is so high, that it couldn't possibly provide enough compliance for traction. It MUST be, right??

Conventional thinking says that IF the bike can go to full extension and stay there, it has to be with a really high AS. The logical next step is that IF the bike has that high of AS, it cannot possible respond to bumps.

I agree fully with the above, under a conventional system. But the Missing Link does have the ability to provide infinite spring stiffness and the steep geometry associated from a fully extended rear, but yet act like a completely normal suspension in the bumps. It is the best of both worlds.

And that's what has this forum in a tizzy. None of the engineers here have been able to understand how this can happen, or even believe that it CAN happen, so it is easier to discredit it.

There's an old saying, something like "you know you're doing something right when your competitors are all yelling that you're doing something wrong"

 

[Tantrum Cycles]

I disagree with you on the pavement stuff, as this is where I usually feel the worst traits of high AS designs come out. On trail, unnoticeable, on pavement, I see it bobbing all the time.

This is another great point. I use my old Super v as an example. Very high AS. The suspension would extend under hard pedaling and compress at the dead spot in the pedal stroke.

 

[slimshady]

how high are you talking about? I'm talking around 120-MAYBE 150%. A granny ring on a bike like the old K2s is going to be well over 200%. With the right value, a bump force should still be able to overcome the chain forces of the bike, allowing it to compress and react to bumps, then you can apply torque effectively on the other side.

I disagree with you on the pavement stuff, as this is where I usually feel the worst traits of high AS designs come out. On trail, unnoticeable, on pavement, I see it bobbing all the time.

I agree with you. The AS numbers on my Rallón are above 100% in every single cog for a 1x11 setup -while not being astronomical- and the way it grabs the terrain is amazing. The bumps you encounter are still able to force the wheel to move out of the way, preventing hang ups. Switching between a friend's Jekyll -a bike with less than 100% AS in every single gear in a 1x11 config- and my Rallón while doing the same track a couple of times turned those nasty characteristics you wrote about to be more evident.

 

[Sandwich]

Now we're getting somewhere. Some want to claim that the AS value on my bike, especially at full extension, is so high, that it couldn't possibly provide enough compliance for traction. It MUST be, right??

Conventional thinking says that IF the bike can go to full extension and stay there, it has to be with a really high AS. The logical next step is that IF the bike has that high of AS, it cannot possible respond to bumps.

I agree fully with the above, under a conventional system. But the Missing Link does have the ability to provide infinite spring stiffness and the steep geometry associated from a fully extended rear, but yet act like a completely normal suspension in the bumps. It is the best of both worlds.

If it's fully extended, then there's no sag to compensate for dips in terrain, is that correct?

There's an old saying, something like "you know you're doing something right when your competitors are all yelling that you're doing something wrong"

we're not your competitors, though you seem to think we all are. we simply seek to understand what you're trying to achieve and substantiate your claims. In the MTB world, designers love to claim "THE NEXT BIG THING" but in reality, it's just 3mm more on each side of your hub.

 

[Tantrum Cycles]

If it's fully extended, then there's no sag to compensate for dips in terrain, is that correct?

This is correct. At the low speeds of a climb steep enough to be at full extension, it just doesn't matter. The bike follows the terrain with plenty of traction, because there is plenty of weight on the rear wheel., it's not like the ground can "fall away", like when you're at speed.

In a prior post, you were concerned about what happened when the wheel strikes the ledge at the other side of the hole. At the moment of impact, the Missing Link activates the shock, allowing the wheel to absorb the bump and maintain traction, as in the case with other bumps. Then, if there are no further bumps, it will immediately go back to full extension and full stiffness, keeping the geometry steep.

 

[Tantrum Cycles]

we're not your competitors,

Correct me if I'm wrong

1) vrock, the original poster of bad data and most vehement in his arguments, has a bicycle linkage design blog with his bike designs heavily on display.

2) hmcleay, next up, also has a website to inform the world of his knowledge of bicycle suspension. He has been known to design bikes, sell them, and seek licensees. Interestingly, he also seems to have contributed to the Linkage software, promotes it and vrock promotes himself on hmcleays' website.

No possible conflict of interest from those 2.

3) darkowl, also appears to be a bike/suspension designer and in fact, seems to be making bikes of his own design.

I would guess that there are other active designers commenting, and I believe there are a couple shock guys also. Most, if not all of these guys, have confidence in their knowledge and think they might have a better handle on it than most. Certainly the first 2 I listed do, or they wouldn't have a website touting their expertise and selling product based on it, right?

It is indeed my competitors that have posted the bad data and claimed it was accurate enough to completely dismiss my claims as pure BS of the highest degree, despite videos showing otherwise. Many others have jumped on that data as "proof", which is unfortunate, but they are not the originators.

 

[Tantrum Cycles]

we simply seek to understand what you're trying to achieve and substantiate your claims.

Right. Which is not going to happen by posting an AS and LR curve. Those are numbers are in a vacuum in this comparison. I didn't go through this trouble to design a suspension that does what every other one can do. I wanted an increased range of geometry and spring force that simply is not and cannot be available using the now traditional tools of AS and LR.

You can't do something different without doing something different. The Audis are a perfect example.

And you're probably going to have a hard time learning much by wading thru all the crap in this thread. Luckily, those with a genuine interest have gone to the videos and website. This thread has been fantastic for that.

If you take the time to watch the videos, you can understand it. They are not the best, I know, but they are real.

I'm still working on my next video, which has some pretty dramatic demonstrations that show the dual nature of the suspension, with and without the shock attached. Today I hope............

 

[AngryMetalsmith]

What will be fun is to revisit this in about 4-6 months or so. Production bikes will be in the hands of customers and reviewers world wide.

Yes it will because that is a bold statement for a company owner who seems to lack the funds for professional graphic design. If you can pull of full production runs of 2-3 frame models and global distribution in that time frame it will be more impressive than if your linkage actually does what you say.

Good luck with that one.

 

[hmcleay]

Now we're getting somewhere. Some want to claim that the AS value on my bike, especially at full extension, is so high, that it couldn't possibly provide enough compliance for traction. It MUST be, right??


Conventional thinking says that IF the bike can go to full extension and stay there, it has to be with a really high AS. The logical next step is that IF the bike has that high of AS, it cannot possible respond to bumps.


I agree fully with the above, under a conventional system. But the Missing Link doeshave the ability to provide infinite spring stiffness and the steep geometry associated from a fully extended rear, but yet act like a completely normal suspension in the bumps. It is the best of both worlds.

Hi Brian,

I’m not sure if you actually read my post #325 (page 9), but we’re in agreement here. The Total Wheel Force graph posted shows that under hard acceleration (climbing), 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’.

I didn’t mean ‘floppy’ in a bad way, it’s just a difficult characteristic to describe. As the force curve flattens out, it means that the wheel rate (which is already relatively low to begin with) reduces significantly even becoming zero (or even slightly negative – wrap that around your head!). There’s no argument from anyone that a lower wheel rate increases traction, since the wheel can follow the terrain perfectly with very little resistance to movement. It is the ultimate in compliance under acceleration.

This is something I have been banging on about for years (although you and I are utilising this characteristic in opposite ways). You might not be interested in looking at it in relation to the AS and LR curves (if you want to do it by FBD’s then that’s your prerogative), but the slope of the AS curve is as important (if not more important) than the actual AS value.

AS value determines the wheel force (and hence the suspension position) under acceleration, AS slope determines the wheel rate.

The high AS value of your suspension tells me that it will extent under hard acceleration (as you claim), and your steeply decreasing AS curve tells me straight away that your suspension will be very compliant under acceleration, due to the effect on wheel rate. Apologies if that was not made clear in my post #325.

Maybe you’re not referring to me in the above quote, but I don’t think anyone here has suggested that your bike will not provide enough compliance for good traction due to the high AS value. And in my analysis of your design in post #325, I agreed that the wheel CAN instantly react to bumps when climbing.

So maybe you need to re-read post #325, and re-think this:

And that's what has this forum in a tizzy. None of the engineers here have been able to understand how this can happen, or even believe that it CAN happen, so it is easier to discredit it.

And this:

Correct me if I'm wrong

It is indeed my competitors that have posted the bad data and claimed it was accurate enough to completely dismiss my claims as pure BS of the highest degree, despite videos showing otherwise. Many others have jumped on that data as "proof", which is unfortunate, but they are not the originators.

I usually try and end these posts on a positive note, but I’m struggling to find something here. You seem to be interpreting these posts differently from what is actually written.

I’m certainly not out here to put down your design, my analysis confirms all the climbing characterics you describe, and I’m happy to revisit my comment about the suspension extending under hard acceleration when going downhill, as soon as the ‘real’ numbers become available.
However I do have problem with people who think their suspension design defies the laws of physics, exhibiting some sort of behaviour that isn’t shown on the AS and LR (and AR) curves. It’s these people who are seemingly intent on maintaining a ‘cloud of secrecy’ about suspension design, so they can regurgitate the same design every few years with a new acronym.

If I had it my way, every bike consumer would be savvy enough to interpret AS and LR (and AR) curves, so that bike designers are forced to think outside the box (AS YOU HAVE DONE) to create something innovative. In case you missed it, this is a compliment.

1) vrock, the original poster of bad data and most vehement in his arguments, has a bicycle linkage design blog with his bike designs heavily on display.

I wasn’t aware that @Vrock designed any of the bikes displayed on his website, can you tell me which ones?

2) hmcleay, next up, also has a website to inform the world of his knowledge of bicycle suspension. He has been known to design bikes, sell them, and seek licensees. Interestingly, he also seems to have contributed to the Linkage software, promotes it and vrock promotes himself on hmcleays' website.

Maybe that’s a typo or something, but there’s nothing about @Vrock on my website.

Regards,
Hugh McLeay

 

[Tantrum Cycles]

Hi Brian,

Maybe that’s a typo or something, but there’s nothing about @Vrock on my website.

Regards,
Hugh McLeay

I apologize. I believe I saw his "must see blog" on the "bikechecker" website, along with your logo. You have been credited with at least helping write the software.

Would you please clarify your connection with bikechecker? I don't mean that in an accusatory way, I just want to know if that's your software.

if I have connected you two in error, my apologies

 

[Tantrum Cycles]

Hi Brian,

I’m not sure if you actually read my post #325 (page 9), but we’re in agreement here. The Total Wheel Force graph posted shows that under hard acceleration (climbing), 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’.

Regards,
Hugh McLeay

I am trying to equate this statement with the way the bike rides and I'm having a hard time. Mainly because of this:

"This means under these conditions, the wheel can pretty much occupy any position in this zone without any resistance".

Because in reality, under hard climbing, the suspension is pretty forcefully extended (until you hit the bump). In the next video( I am currently way behind on publishing), I can jump up and down on the bike (with or without the shock!) and, as long as I'm maintaining pedaling force, there is NO movement at all from the rear suspension.

If your above statement is true, wouldn't it move, at least a little? It would have to have MASSIVE LSC to prevent movement form damping alone.

Would you explain this conundrum ?

 

[Tantrum Cycles]

Yes it will because that is a bold statement for a company owner who seems to lack the funds for professional graphic design. If you can pull of full production runs of 2-3 frame models and global distribution in that time frame it will be more impressive than if your linkage actually does what you say.

Good luck with that one.

Hi Angry,

"lack the funds" isn't exactly right. More like, "have at least 100 things that are a higher priority to me". Like production, demo bikes, eurobike, interbike, etc. Massive expenditures that I think are more important.

Yes, when I pull this off, I'll even be impressed. This is a huge undertaking, with many hats not able to be paid for, yet. But, my "plan" seems to be working and we're on schedule to deliver bikes this year.

I will take your good luck wishes, thanks.

 

[Tantrum Cycles]

However, when cornering/pumping/jumping etc, the initially very high wheel rate would surely make it incredibly harsh each time you make contact with the ground.

Hugh,

i am grabbing one of your earlier posts. In your above statement, you are echoing one of vrocks' assertions.

The thing that clashes with reality is, that at full extension, there is very little force on the spring. For example, a coil with no preload would have zero force. Obviously, an air shock with a negative spring is a little trickier to determine the force without the shocks' exact data, but it's still a pretty low force.

It has to be, right? Otherwise, the bike would never sag when I sat on it. BTW, operational sag can be between 25 and 35 percent, with the resultant change being what you might expect from any bike.

So how can the bike be harsh when contacting the ground? Are you counting AS in the situation when the wheel is off the ground?