Is that all there is? Yeti vs Orange

Jm_ · Jul 3, 2016

No, the Orange increases from about 115 to 160% AS through the travel on the chart. The Yeti drops off through the travel. On a bump that uses about half the travel, the yeti is still hanging out around 115%, while the Orange is up at 140%. I think what you are seeing here are classic high-pivot characteristics. This means that the Orange will have more "lockout" while pedaling over the rough stuff, as in loss of traction. With this style of suspension, I find it's difficult to pedal standing over the rough, as it breaks traction easily, even seated it will do the same. Pedaling over rough terrain should induce more feedback/choppy suspension action as well.

What is similar is the AS profile in similar gear combos at sag point, but sag point is just when the bike is stationary, not when you are riding on the trail. I think the whole "pedaling zone" thing is BS. You encounter bumps on climbs, big and small, you sometimes sprint, then sit down, all of these things change the point at which the rear suspension is, relative to it's travel. When I'm riding, my rear suspension is working all the time. If it wasn't, I'd be riding a hardtail or rigid bike on said trail. This is where I can tell the difference in suspension traits with something like the falling-AS profile of the horst-links I've owned. Each pedal stroke is an acceleration, and when the suspension starts cycling through bumps, you get further into the travel, where there's dramatically lower AS, which puts more of your energy into compressing the suspension, which is already past the sag point, and so you end up huffing and puffing more than you need to. The high AS single pivots go dramatically in the opposite direction. I've had a few of these too, incredibly poor bump absorption IME. My old K2 seems to be the closest.

I think the yeti is an attempt at replicating some of the AS qualities of DW without infringing on the patent. It's not the same, but it does have a "flatter" mid-travel curve, which is a feature of the DW.

On the single-pivot side, I think the Evil bikes and a few others are what to strive for, flat-ish AS curves close to 100%, rather than wildly above or below. I've had several lower-pivot single-pivot bikes and they can be absolutely great.

Jm_ · Jul 3, 2016

Yes, I think you are missing something, but I'm done here! Moved on from high pivot single-pivot bikes years ago, for good reasons.

norbar · Jul 3, 2016

Happymtb.fr said:
Thank you for your feedback @Jm_ !

By pedalling zone, I meant something like the first 2/3 of travel (maybe with the very beginning of the stroke left out since one need to have the back wheel on the ground in order to transfer energy ).

Interesting point based on experience about the level and profile of the AS curve.
@hmcleay did mention it as well in this post: http://ridemonkey.bikemag.com/threads/videos-mtb-rear-suspension-series.275496/page-3#post-4132602 nevertheless he did not point toward key numbers but the bike he designed has a rising AS curve from 95% to 165%
I am no expert and I did not try that many different bikes to have my own opinion, so I am not telling that one of you is more right than the other!

Back to yeti vs orange: the Alpine has now a rising AS profile in the pedalling zone while the SB6 is more flat to slightly decreasing in the same zone. I don't think that the last 60mm of travel will be used during pedalling.
The rest is pretty damn close which makes me wonder if one is better than the other or if they perform equally suspension-wise.
Am I missing something?
We can leave carbon vs alloy and geometry for later, thanks!

I think what you are mising is that anti squat is derived from axle movement/path. That means chain stretch/kickback, how the susp behaves when not pedaling, how geometry changes with suspension movement. There are many factors to keep in mind here besides AS and Leverage ratio but I'm not equiped or rested enough to explain it alll. For the most part you can make a single pivot to be similar to some virtual pivot designs but they will never be the same (small differnces are more noticeable than you think) and virtual pivot designs simply give you more freedom as a designer. They are not magical ideas to make suspension 128 Ellsworth% better, they won't make your bike "push of obstacles" or go on an "s shaped wheelpath"
The alpine has similar kickback at the start but it grows going through tavel at the same rate while the yeti slows down. That means it is easier to stay on the pedals when using full travel. As someone riding a bike with quite a bit of kick to it I have to say less of it is nice.

Udi · Jul 4, 2016

@Happymtb.fr I don't think you're missing anything. The infinity *would* allow for some cool characteristics (while avoiding infringing existing patents) IF Yeti knew what they were doing - but unfortunately they really haven't done anything with that design that they couldn't have with a simpler design (one that doesn't involve two extra points of wear and sliding friction).

I think the small amount of progression on the Yeti in this case does make it a (slightly) superior choice to the Alpine, dead flat leverage curves are not good on any bike - and especially not on bikes designed to work with air shocks. I use the word "designed" loosely here, as neither of these bikes are particularly good.

The falling AS @ end of stroke (Yeti) is preferable to the steadily rising AS on the Orange - but just like the leverage curve - neither bike is optimal. You generally want AS to be falling after the midpoint of travel to avoid pedal kickback effects, but these are minimal under coasting / DH scenarios anyway (since PK is dependent on forward velocity when coasting).

Antonio who runs that blog site is a very competent user of the Linkage program so I imagine he would have modeled the double pumper with reasonable accuracy.

norbar · Jul 4, 2016

Just remember most bike designers don't really know exactly what they are doing. I'm a hack who has to ask Udi and a few other friends for susp explanation half the time yet I still look at many current designs and I see that it's more guesswork than real knowledge. The funny thing is with a decent shock the suspension won't feel super bad unless you really fuck up the curves. Hell I liked the Knolly Warden i tried for a few rides and only Steve M pointed to me that I must have been drunk. Also Santa Cruz bikes still sell like hotcakes so yeah

profro · Jul 4, 2016

@Udi , curious but from a bike design standpoint what is superior? I'm just curious if design and actual ride feel overlap.

shirk007 · Jul 4, 2016

Orange would do good to make some minor changes to the bike to clean up the kinematics.

Move the pivot into a spot similar to Evil or Saracen to clean up the AS.

http://linkagedesign.blogspot.ca/2014/01/saracen-ariel-650b-2014.html
http://linkagedesign.blogspot.ca/2015/11/evil-insurgent-275-2016.html

Then tip the nose of the shock down similar to what they have done on the 322 to get a more progressive LR.

http://linkagedesign.blogspot.ca/2012/10/orange-322-2013.html

Or at least that is what I've come up with in my hack research / building of a single pivot.

My version came out like this. I don't have the exact profiles from Linkage as I only played around in the demo version then just winged it in building.

If throw out the need for a bottle mount and a disregard for certain aesthetics (shock placement and angle) a simple single pivot can be made to ride pretty damn good.

Udi · Jul 4, 2016

I don't mean any offence (and the home build looks great, especially that seat angle!), but a delta of 0.1 in leverage ratio doesn't really constitute "progressive" to any significant level of usefulness, and I don't think it actually achieves particularly desirable characteristics.

However, I've experimented with the same design (mostly as a proof of concept). Generating any useful delta in leverage curve relies on large angular change between the shock e2e plane and the member/s it mounts to. If you use an average leverage ratio that is similar to a linkage bike, you can never achieve anywhere near as aggressive change in leverage curve, because lower leverage ratios reduce the amount of angle change you can get from a single pivot design.

So what's the solution?
Run a higher average leverage ratio - a shorter shock for given travel. It's often touted as a bad thing, but it's actually the best way to get a useful delta in leverage curve on a pure single pivot. It allows pivot and shock orientations that generate angles which closer approach a linkaged bike, and the superior LR curves possible (substantially more progression than the design above, at least) far outweigh the disadvantages of the higher average leverage.

Sidenote:
If anyone ever wondered why the Yakuza Kumicho used a 2.75" stroke shock to get 8" of travel instead of the 3" used to get the same travel in the Sunday (or 223/224/322 etc), it wasn't for cost reasons. It's because wizard Weagle knew the above relationship, and exploited it to build a pure singlepivot DH bike that singlehandedly destroys every effort Orange has ever made at the same thing, including the 322. 11 years ago.

shirk007 · Jul 4, 2016

Like I said, it's just hacking around on my part. At the time in 2014 when I was working it out my thinking was that linear would be better than regressive ala the old Heckler.

I wasn't pointing out that the 322 was great...just that in context of their own bikes they have produced something other than pure linear/regressive.

What would be considered an okay delta?

The Process 134 has a delta of roughly 0.2. Looking at the new Troy and the Spartan Weagle aims for about 0.7.

shirk007 · Jul 4, 2016

http://linkagedesign.blogspot.ca/2014/11/gt-sanction-275-2015.html

The Sanction gets a larger delta than the ICB. 0.25

csermonet · Jul 4, 2016

Udi said:
Sidenote:
If anyone ever wondered why the Yakuza Kumicho used a 2.75" stroke shock to get 8" of travel instead of the 3" used to get the same travel in the Sunday (or 223/224/322 etc), it wasn't for cost reasons. It's because wizard Weagle knew the above relationship, and exploited it to build a pure singlepivot DH bike that singlehandedly destroys every effort Orange has ever made at the same thing, including the 322. 11 years ago.

I notice the Yakuza Kumicho gets brought up often when talking about good single pivot designs... I rode one for like 3 years, sold it probably 4-5 years ago. It was the bike that really got me into mountain biking, i progressed alot on that frame and my tech skills base definitely comes from the time i had on that bike. I didn't know much about bikes and definitely didn't know the Yak was such a good SP back when I was riding it though. What was it about the Yak that made it so good, the leverage curve? You mention the Yak destroys every thing Orange ever made including the 322, are you talking about something specific like the leverage or AS curve, or do you just mean the bike overall? And do you mean the Yak is better than just the DH stuff they've made or all their bikes? Sorry to get off topic here..

norbar · Jul 5, 2016

csermonet said:
I notice the Yakuza Kumicho gets brought up often when talking about good single pivot designs... I rode one for like 3 years, sold it probably 4-5 years ago. It was the bike that really got me into mountain biking, i progressed alot on that frame and my tech skills base definitely comes from the time i had on that bike. I didn't know much about bikes and definitely didn't know the Yak was such a good SP back when I was riding it though. What was it about the Yak that made it so good, the leverage curve? You mention the Yak destroys every thing Orange ever made including the 322, are you talking about something specific like the leverage or AS curve, or do you just mean the bike overall? And do you mean the Yak is better than just the DH stuff they've made or all their bikes? Sorry to get off topic here..

Susp wise Yak is better. Orange for some reason seem very insistent on making bad or at least outdated designs (224 wasn't so long ago...). They even had prototypes that looked like a better choice but just didn't pursue that idea for some insane reason.

Geometry wise they are better than the yak so it may ride decent if you get good damping.

hmcleay · Jul 5, 2016

Happymtb.fr said:
Like @norbar said the geometry on the 324 is more up to date. Then when comparing them on linkage, the Orange is better performing when considering AS and AR, the delta of the LR is better for the Yakusa.
View attachment 122766

EDITED: I was reading the wrong colours on the graph!

Yes, based on those curves, I'd also rate the Orange as a better pedaller than the Yakuza.
The Yakuza has significantly more AS at sag, but it's too much (around 170%), and would extend the suspension on each pedal stroke.
The Orange has what I consider the 'sweet spot' for AS, around 120% at sag. 100% addresses the compression due to horizontal acceleration (and the associated weight transfer), and the extra 20% addresses the compression due to vertical forces (due to vertical acceleration of your body that is present around the middle of the pedal stroke).

Importantly, the slopes of these curves are completely different.
The Yakuza, having a negative AS slope, reduces its wheel rate when pedalled. So while it might extend when pedalling, if the suspension is interrupted by vertical forces (e.g. body motion - highly likely) or by rough terrain (also highly likely) then the suspension will compress further than it would have if you weren't pedalling at all.
The Orange, having a positive AS slope, increases its wheel rate when pedalled, which is ideal because the rear suspension is carrying more of the rider's mass when accelerating. Therefore the natural frequency of the suspension remains approximately the same whether you are coasting or pedalling.
Of course, this type of AS curve comes at a price - increased pedal kickback.

I haven't ridden either of these bikes, so I'd be interested to hear how that analysis correlates with real world experience.

Sandwich · Jul 5, 2016

If you want an excellent example of a well executed single pivot, the Guerilla Gravity DH frame is a good choice. It doesn't have the best AS values, but I think there is acceptable debate on what is best for a DH frame. The leverage ratio, however, is about as good as you can get with a coil shock and no linkage.

FWIW, I rode a Yakuza and a Morewood back to back extensively during a single season. The Yakuza was one of my favorite frames. It pedaled acceptably, and it motored pretty well through the rough stuff. It jumped very well, oddly enough. Honestly, that bike did nothing wrong (besides break, easily, and every bike I've seen in person has broken at the same spot-shock eyelet). It was easy to ride, fit well, and did nothing wacky, like blow through travel or brake jack or etc. It did crack though.

The morewood was similar, but a little worse. It blew through travel a little more easily. A vivid air helped in this regard, but it was stiff off the top. Didn't matter too much once you got going, but felt pretty terrible in the lot. I didn't notice pedal kickback. A lot of people complain about it, but I'm still uncertain that this isn't primarily a problem on paper. It did suck for my drivetrain, however, and the shitty LX derailleur I had on there took a beating from all the chain stretch.

One other point, linear bikes are a love/hate affair, I think. I think they are spectacular in rough DH tracks. They easily take on high speed rock strewn sections without concern, as they don't tend to pack up with excessive compression at the end of the stroke. The flipside of that is that they are tough in big g-outs and jumps. Without progression to boost off of lips, they're kind of pigs to bounce around. I'm now on a GT Fury, and the shock rate isn't that dissimilar to the yakuza, I don't think. An RC4 shock with the reservoir turnt up helps give some end stroke bottom out resistance, and it's made a big difference compared to the Van RC I had before.

kidwoo · Jul 5, 2016

shirk007 said:
What would be considered an okay delta?

(IMO)
Trailbike: 1

DH bike: 1.5ish

That's assuming relatively linear curve shapes though.

Sandwich said:
One other point, linear bikes are a love/hate affair, I think. I think they are spectacular in rough DH tracks. They easily take on high speed rock strewn sections without concern, as they don't tend to pack up with excessive compression at the end of the stroke.

Horse pucky

It's exactly in successive hits that they suck. That 'excessive compression' helps lift the bike and carry it over things by smoothly changing the wheel rate over time and gradually applying more resistance. Overly flat leverage curve bikes just let the wheel swing out of the way really easily force-wise without helping to lift the bike, which not only DOES pack them up, it makes them harder to skip over things.

It's the difference between riding a vehicle and being an active participant in the system. Baja cars (and to a lesser extent, motorcycles) have suspension designed to maintain vehicle attitude because the vehicle is the biggest mass in the system. There's not as much user input as a bicycle. I mentioned motos because that's kind of the hybrid between the two. Your biggest suspension component on a bicycle is still your legs and body, not to mention all the different ways you can influence how that suspension is being used with body position and body motions.

Flat leverage curves are for cars. Or riding sitting down.

Or all the dentists that just showed up to ride flow trails that don't know where to turn unless a berm points them somewhere. It's a passive setup.

Is anyone going to say the V10 is a bike you can't plow through things on? What about a YT Tues? Look at the leverage curves on those things. And more importantly, go ride them.

There's a good reason pretty much all of the better riding bikes have leverage curves that look nothing like what orange has made forever.

shirk007 · Jul 5, 2016

kidwoo said:
(IMO)
Trailbike: 1

DH bike: 1.5ish

What trail bikes have a LR delta of 1?

Just looked at the Range and it's just 0.5, Megatrail is less than 0.5. Reign and Spartan are in the 0.7 range.

With a single pivot I think the best I can do is mimic the GG DH.
http://linkagedesign.blogspot.ca/2015/02/guerrilla-gravity-dh-2015.html
Delta of 0.55

Okay so the perfect single pivot LR is pretty much what GG did...now where is the perfect spot for a trail bike to position that main pivot? Let's design my next garage build project here.

kidwoo · Jul 5, 2016

Easy there cowboy. "perfect leverage ratio" or "most reasonable for a single pivot with no shock linkage without fucking everything else up"?

Those two aren't necessarily the same.

As far as a delta 1 bike, this one is close: http://linkagedesign.blogspot.com/2012/12/turner-burner-650b-2013.html

This one goes further: http://linkagedesign.blogspot.com/2014/02/young-talent-capra-2015.html

As far as what you build next? Go ride those two bikes (a turner 5 spot is the same as that burner as far as LR goes) as well as a shit ton more and see what YOU like.

Then make friends with a machinist who can cut you a shock link

Wuffles · Jul 5, 2016

kidwoo said:
(IMO)
Trailbike: 1

DH bike: 1.5ish

That's assuming relatively linear curve shapes though.

Horse pucky

It's exactly in successive hits that they suck. That 'excessive compression' helps lift the bike and carry it over things by smoothly changing the wheel rate over time and gradually applying more resistance. Overly flat leverage curve bikes just let the wheel swing out of the way really easily force-wise without helping to lift the bike, which not only DOES pack them up, it makes them harder to skip over things.

It's the difference between riding a vehicle and being an active participant in the system. Baja cars (and to a lesser extent, motorcycles) have suspension designed to maintain vehicle attitude because the vehicle is the biggest mass in the system. There's not as much user input as a bicycle. I mentioned motos because that's kind of the hybrid between the two. Your biggest suspension component on a bicycle is still your legs and body, not to mention all the different ways you can influence how that suspension is being used with body position and body motions.

Flat leverage curves are for cars. Or riding sitting down.

Or all the dentists that just showed up to ride flow trails that don't know where to turn unless a berm points them somewhere. It's a passive setup.

Is anyone going to say the V10 is a bike you can't plow through things on? What about a YT Tues? Look at the leverage curves on those things. And more importantly, go ride them.

There's a good reason pretty much all of the better riding bikes have leverage curves that look nothing like what orange has made forever.

I think far too many people like to research motosport suspension and apply it to bike designs, which fails for exactly the reason you mentioned. For shock design, motosport probably is a great place to seek inspiration, but not the linkages themselves.

I was part of a SAE Baja team and thanks to the extremely limited power ceiling (I think it was like 8 HP in 2008?, they're up to 10 now) we did everything possible to keep the weight down. To the point where the driver became a significant fraction of the sprung weight (we were 120kg or something). So we started looking at a linkage design for the suspension, pretty simple 1.5:1 cantilever. Even that was too progressive, we ran the buggy over some washerboard and it started bouncing higher and higher until it flipped. Good test for the roll cage, but we stuck to linear after that. Probably could have ironed it out, but would have killed us on the cost.

shirk007 · Jul 5, 2016

kidwoo said:
Easy there cowboy. "perfect leverage ratio" or "most reasonable for a single pivot with no shock linkage without fucking everything else up"?

Those two aren't necessarily the same.

As far as a delta 1 bike, this one is close: http://linkagedesign.blogspot.com/2012/12/turner-burner-650b-2013.html

This one goes further: http://linkagedesign.blogspot.com/2014/02/young-talent-capra-2015.html

As far as what you build next? Go ride those two bikes (a turner 5 spot is the same as that burner as far as LR goes) as well as a shit ton more and see what YOU like.

Then make friends with a machinist who can cut you a shock link

Moving to a linkage adds a level of complexity that requires more equipment and cash. I like the fact that I can get something that rides reasonably well with just hand files, bench vise, and limited tooling.

Finding a Turner around here is rare, closest might be a Pivot Firebird.
http://linkagedesign.blogspot.ca/2013/12/pivot-firebird-275-2014.html

But pretty sure I know someone with a Capra that I could swing a leg over.

Either way I think 0.5 is the most I'll get in a single pivot so we're in the range of the Range/Sight. I rode a borrowed Sight for a day of proper thrashing in Whistler and really liked it.

Wuffles · Jul 5, 2016

shirk007 said:
What trail bikes have a LR delta of 1?

Just looked at the Range and it's just 0.5, Megatrail is less than 0.5. Reign and Spartan are in the 0.7 range.

With a single pivot I think the best I can do is mimic the GG DH.
http://linkagedesign.blogspot.ca/2015/02/guerrilla-gravity-dh-2015.html
Delta of 0.55

Okay so the perfect single pivot LR is pretty much what GG did...now where is the perfect spot for a trail bike to position that main pivot? Let's design my next garage build project here.

Nomad is about .8 from sag.

Capra is 1.3 total, .8 from sag.

RM Thunderbolt is 1 total, about .75 from sag.

Udi · Jul 5, 2016

Just so no one gets the wrong idea - I just meant the Kumicho is good for a non-linkaged single pivot (also I was comparing it to the 322, this is the first I've seen of the 324 - and I'd buy neither). As a general rule it's not 1926 anymore and we should all have linkages on our DH bikes - they are superior all round.

There is also such thing as too much progression and it manifests itself as a noticeable drop in stability, since the bike blows through the first half of travel very easily and then becomes difficult to use all the travel on. The amount of progression is generally tailored to the particular shock that is to be used in the frame - and this varies substantially between air/coil shocks, and also even within those classifications. A modern-can-equipped air shock is NOT linear in spring curve (not even close if you look at a graph) and this is important to note.

The other point I'd like to make very clear is that you can't properly optimise a frame for an air shock without an linkage - so unless you run a coil shock, a non-linkaged singlepivot will always be a noticeable compromise. With a coil shock you can have less compromise, but it's still not going to be as good as a linkage allows.

Also as a side note, I was just using the LR delta *value* thing as a simple way to compare two bikes - but this isn't really accurate for comparing between bikes of grossly different average leverage ratio, it's more accurate to calculate a *percentage*.

Bottom line - non-linkaged single pivots are virtually always inferior (even with a coil shock and careful pivot placement).

@shirk007 - I think as a general rule, a Weagle design is always a good one to follow. Kona not so much. YT are a good example of excessive progression in my book. Maybe go the extra mile and put a link in on the next one - personally I don't think the simplicity of not having one justifies the drop in performance.

@csermonet - See above RE: non-linkaged singlepivots, apologies if I gave the wrong idea. A bike with a linkage (assuming the designer had a rough idea of what they were doing, unfortunately not all do) is usually better.

Jm_ · Jul 6, 2016

Another benefit of linkages is the elevated-seat-stay design that Orange uses is very susceptible to rear-end flex, basically any force that is not perfectly in line with the shock/suspension will cause a large twisting moment, which due to the fact that there's no linkage or triangulated swingarm, will concentrate that force on the shock and the pivot-mast coming out of the main pivot. You can make this pivot as large as you want, the forces involved will still cause this to happen. I sent off more than a few shocks to get rebuilt from bikes with this general design, but more important to me is the rear end flex while riding. Foes even went so far on single-pivot bikes to add non-shock-rate-modifying linkages that only served to stiffen the rear triangle, because of this issue. The gorilla gravity is a much better design in this sense, although still single pivot with no linkage, it puts the chainstays right behind the pivot with no extended "mast" that would allow for flex.

IMO, this is another big reason why bikes like the Super 8, K2 Evo, and the myriad of copies have fallen largely out of favor. You are also trading one form of reliability for another (linkage bearing and shock durability/seals/bushings).

mtg · Jul 6, 2016

kidwoo said:
(IMO)
Trailbike: 1

DH bike: 1.5ish

That's assuming relatively linear curve shapes though.

Using a delta works, but is not normalized for total average leverage ratio. So, the best way to compare is % change from top out to bottom out, which is the number that frame manufacturers use with shock companies to come up with tunes.

For example: comparing number of teeth on a cassette. "The 10 tooth is only 1 tooth smaller than the 11 tooth, it can't be that noticeable". It's a 10% change, which would be an equivalent change to a 46t up top vs a 42t. Tooth delta doesn't normalize for cog size, same idea above.

mtg · Jul 6, 2016

Udi said:
As a general rule it's not 1926 anymore and we should all have linkages on our DH bikes - they are superior all round.

I disagree. You can create a wide variety of kinematics sans linkage on a DH bike that I would argue are a very good place to be.

TrumbullHucker · Jul 6, 2016

Dogboy · Jul 6, 2016

TrumbullHucker said:

A bunch of opinions (some quite strong) based on charts generated by computer program and not by actually riding bicycles.

StiHacka · Jul 6, 2016

Dogboy said:
A bunch of opinions (some quite strong) based on charts generated by computer program and not by actually riding bicycles.

profro · Jul 6, 2016

Dogboy said:
A bunch of opinions (some quite strong) based on charts generated by computer program and not by actually riding bicycles.

That is why I wanted someone to tell me what bikes are best based on "numbers" and I wanted to compare to how they "rode". My suspicion is that they don't overlap.

kidwoo · Jul 6, 2016

mtg said:
Using a delta works, but is not normalized for total average leverage ratio. So, the best way to compare is % change from top out to bottom out, which is the number that frame manufacturers use with shock companies to come up with tunes.

Right. He asked for deltas, and for the generally two scenarios for every travel range I've ridden, I still say that would be close. I should have said 1-ish, with the shorter shock option on the slightly, <1, longer 1.

For this theoretical 160mm travel bike with a delta of 1 that shirk would build, it's only going to have one of two total average ratios. One for a 2.5" shock and one from 2.25. If you take a simple linear slope that's 1:2.52 and 1:2.8. That would still be in the ballpark. Ballpark meaning 0.8 to 1.2

ish

Udi · Jul 6, 2016

mtg said:
Using a delta works, but is not normalized for total average leverage ratio. So, the best way to compare is % change from top out to bottom out, which is the number that frame manufacturers use with shock companies to come up with tunes.

I did mention this (see post #27), however I think the % change from top out to bottom out doesn't tell the whole story, particularly on trail bikes designed for air shocks where the location of the change is just as important as the magnitude of the change. Obviously shock companies just need ballpark values for ballpark tunes, but when you're talking about creating an ideal wheel rate curve with a fixed spring curve on a shock, then you need to apply your LR changes in very specific regions of the travel. It's this position-specific magnitude that you can't address particularly well without a linkage.

mtg said:
I disagree. You can create a wide variety of kinematics sans linkage on a DH bike that I would argue are a very good place to be.

I do think on a DH bike you can do a reasonably good job, yes (thanks to coil shocks), but on a trailbike (assuming an air shock) the point I mentioned above comes into play and makes a linkage more desirable. I'm not entirely sure if this forum is about DH or enduro anymore (if everyone could PM @Sandwich asking, that would be great, he isn't replying to me) but I think we're considering both here.

I think on DH bikes there are still substantial advantages to a linkage though:

1. Shock size / length not limited by amount of progression desired - potentially important for longer runs w.r.t heat and related inconsistency. See commentary in above posts on angle change on non-linkaged SP (greater angle change = greater aggression in LR change) having an inverse dependency on shock length. I'm sure you're aware of all that.

2. Shock position less restricted by leverage curve - shock mass can be lower and more central. Yes the rider CoM far outweighs that stuff, but better is better and some want the best...

3. General decoupling of performance characteristics. This is why linkages rock! Because you reduce the dependency of one performance characteristic on another . This is why i-track is probably the best suspension design from a performance standpoint - not because I agree with the final choices of performance characterstics (or even that I want to buy one) - but because the design allows you to do whatever you want with each facet of suspension performance independent of others. Want a particular AS curve with a completely independent LR curve and independent axle path? That's what i-track can do.

Obviously at each step of gained independence, we also gain complexity (and weight) - which is precisely why while I think i-track is an awesome design, I have no intention of riding one personally (at least, yet). But - there's plenty of middle ground here where we can get some performance decoupling benefit at reasonable weight and strength. Other basic linkaged bike designs are pretty competitive in both weight and strength these days, and cartridge bearings are easy to replace + only destructive to themselves as they wear in most designs, so I think a simple linkaged design is a winner these days.

I do think it's possible to make a good non-link singlepivot (and the GG bikes are an example of excellent single pivot optimisation), I just prefer linkages personally - I suppose this is why we have choices and opinions...

But I wouldn't be Udi of RM if I didn't force mine down everyone's throat.

HAB · Jul 6, 2016

kidwoo said:
For this theoretical 160mm travel bike with a delta of 1 that shirk would build, it's only going to have one of two total average ratios. One for a 2.5" shock and one from 2.25.

Unrideable. He needs to use a metric shock.

Not that that in any way changes your point.

'size · Jul 6, 2016

so, is the 2016 giant trance frame i'm considering picking up going to be ok to ride from a numbers perspective?
how about from a 'wheeeee!' perspective?

i will be running it with 26" wheels and fork until i wear out my stock of lil' tires (this should amp up the 'wheeeee!'). hell i may even continue after that.

Sandwich · Jul 6, 2016

kidwoo said:
Horse pucky

You're right, what I actually said was a load of garbage. I think I meant excessive ramp being detrimental to super go-fastness through chunder, but I still stand by saying that a largely linear center portion of the curve is pretty good/preferable when going fast. Some end stroke ramp is better, and more progression is certainly better for jumps. Maybe it's just cause I'm a fat fuck and can't bunny hop for shit.

Is that all there is? Yeti vs Orange

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