Forget Horst, ICT, D-W; here's the holy grail (Merged thread from 4 boards)

[Steve from JH]

I first heard about this a week or so ago:

http://www.feltequilink.com/

Since then, when not riding my bike, I've been thinking about this design. I've decided it's probably the real thing.

What you have is something that looks like a D-W link but with an extra vertical link connecting the rocker and bottom links. The seat stay and chain stay are carbon and are not connected vertically, so you have a "V" instead of a triangle. The carbon is designed to flex vertically but not horizontally. In fact it has to flex in order for the linkage to move because the rear pivots get farther apart in compression and closer together in extension.

The result is an axle path that is close to a vertical straight line. This means the axle path perpendicular is approximately a horizontal line throughout travel, as though you had a very distant fixed pivot at about the height of the axle.

The advantages would be very low pedal feedback and a highly active suspension. Braking would be like with a parallel floater that always stayed parallel to the ground, making it even more neutral than a real floater. This gives traction advantages. There would also be traction advantages when pedaling, since the loss of thrusting force at the ground would not cause suspension movement.

If it were not for the equilink itself, this kind of axle path would produce very little anti-squat, compared with, say, a D-W link. The bike would tend to squat in the rear with every pedal stroke. But the equilink changes that. Its connecting pivots can be placed to give a leverage bias in favor of extension from the force of the chain tension pulling the axle and BB together. This means that a good amount of anti-squat unrelated to the chain angle can be tuned into the suspension, without producing pedal feedback. You could set it up so that in a middle range gear, at sag, the bike had 100% anti-squat and zero pedal feedback. It would develop some feedback with compression travel, but it would still be very low.

No other design, except for URT's, can claim this. And URT's have all kinds of other problems and have been abandoned as a design.

Unless there is some unforeseen problem, I predict you'll be hearing a lot about this design in the future.

Remember, you heard it here first.

[Steve from JH]

DT should license and build some of these:

http://forums.mtbr.com/showthread.ph...59#post2178859

[Jaybo]

Originally Posted by Steve from JH

DT should license and build some of these:

http://forums.mtbr.com/showthread.ph...59#post2178859

We shall see how it rides. I love new technology! But, even more, I like good customer services and pivots that last forever...like a Turner.

Jaybo

[CharacterZero]

The fact that you are compelled to post this in so many different areas draws from your crediblity, and only serves to fragment the ensuing discussion.

[TIMBERRR]

Get that FELT garbage out of here!!!!!

[Jerk_Chicken]

Just in the nick of time because I suddenly felt that my Turner's rear suspension wasn't working anymore.

Oddly enough, it coincided with me finally getting used to the TNT name. Might need a new buzzword to help me get the riding bug back.

[MartinS]

Saw Seamus Mcgraths at Transrockies, definately looks well executed, he did pretty well on it too.

[indyfab25]

I like it...it seems to make perfect sense.

[cactuscorn]

a red link? but that wont go with my new blue turner jersey. guess ill have to pass.

but really, it looks interesting. but as i say with anything newer, better and a zillion % efficiant, time will tell if it lives up to the marketing hype. when jim felt was still behind the wheel, you could count on good things. i hope this will be true again here.

[SMR]

Steve,
how many different forums did you post this on?? Getting a little excited about something no one has ever seen in person or ridden yet? Who knows maybe it will be the greatest, I'll give it a couple years to prove itself.

[Structure]

If what I read on the magazine reviews is right the bike looks great in other respects too. Five inches travel, but light. I don't need freeride tough, but I do want a smooth efficient ride. Nice to see another contender.

[Thylacine]

Actually I didn't read it here first. Brian Caulfield of Kavik bikes was the first to do that design, and clearly Felt have snaffled him up because very little info can be found about Kavik anymore.

I tried looking for pictures of the prototype he did some 3-4 years ago but for some reason can't find any pix of it on the net whatsoever.

[derby]

Originally Posted by Steve from JH

I first heard about this a week or so ago:
. . . . .
Remember, you heard it here first.

Oh that? It's old news. I heard about it before in General, AM, and Other Manufacturers first.



Welcome back!

[ferday]

thanks Steve. i hadn't seen that.

what a sweet feedback loop....amazing it hasn't been tried before.

[Thylacine]

Thankfully, no Felt goons raided my CD collection last night.

[roy harley]

Do you know if the Equilink is a Felt own technology or is it a collaboration with someone or some group/company? I am just wondering if we will see other companies with the same Equilink or if this will be a licensed technology like what happened with the Horst link and ICT.

[Blue Shorts]

Hey Steve... It sounds great, but did you get a gander at the rear wheel? It's waaay behind the seat tube. I'm curious what the extra long wheelbase and long chainstays will do to the handling.

It is interesting, though.

[Thylacine]

Well let's add one and one up shall we.

Type in 'Kavik' into google images and instead of a dozen or so images (including pix of the frame as shown above) like you used to, you get....one pic.

Mr. Caulfield isn't credited on the Felt site, so I would suspect they have either purchased the design from him or just done it anyway and Brian has had to sell his business to pay for the legal fight!

If he's licenced the design I would suspect there'd be a sticker on there saying 'BC Link' or whatever but that doesn't seem to be the case.

Velly Inneresting.

[totally_fixxated]

Looks similar to the Full-Floater suspension on Suzuki dirt bikes.
I have always liked Kaviks modular dropouts!

[cjh_mtb]

They even know how to spell vertical!



It's so compelling

[r1Gel]

Originally Posted by Steve from JH

I first heard about this a week or so ago:

http://www.feltequilink.com/


Remember, you heard it here first.

First to hear about equilink or your impressions of it? I saw and read about equilink months ago , and thought, "Boy, Dave Weagle is going to be a rich man with all these copy cats..."

[Quattro]

Has anyone ridden a Kavik or a Felt with this suspension, to see if it actually works as the computer says it does?

[UP Dude]

It certainly looks impressive. It surprises me that innovative designs are still being released. I have a feeling that we are going to get into an era where everyone settles into their suspension design of choice (in Rocky Mtns case, 5 choices ) and new suspension designs will taper off. However, the similar prior design from Kavik is an interesting twist. Dwuh, nuh, nuhhhh......

I really like the idea of a vertical hub path. I've thought for some time now that a truely vertical hub path may have some benifits. It can't be vertical through the whole travel, chain growth would be a bit out of hand. So if the travel here is actually vertical, I'm interested to try it.

The one problem I have with it is that it relies on the flex of the rear triangle to move through the travel. It has always been my feeling that a suspension needs to be as stiff as possible (laterally and in line) as to transmit as much of the force as possible to the spring/damper unit. I think a suspension can do a better job if the shock is responsible for all of the vibrations, without uncontrollable variables in the system.

I've never liked Trek Fuels, just not active. This design is completely different, so it may not have the same characteristics. I'm also curious to see if they can make bikes with longer travel. Trek tried to make the liquids with flexing stays and it didn't really work. Now for '07, even the Fuel EX gets a proper pivot. But it does give that snappy, responsive feeling that XC racer types live for. Which is great for racers, but maybe not as much for everyone else.

Time will tell. If they have demos in Vegas, I'll do my best to try one and report back.

[_dw]

The equilink is governed by the same physics as the rest of the world. The suspension produces some sort of anti-squat curve, and that coupled with the leverage rate is going to govern how the bike responds to acceleration force input. Its that simple. If it makes it easier to comprehend, think of it as a 5-bar link instead of a 4-bar. There is no "feedback loop", no magic voodoo, and certainly no religious intervention.

dw

[igorion]

the system has a fixed axle path, and thus is subject to any benefit or problem any other traditional (mono pivot or four bar) system has.

the axle path is not perpendicular by any means, it has a center of curvature that may even fall within the tire radius.

so, not better or worse than any other system from the beginning.

i have spent quite some time playing around with the mechanics of this system and while it has some serious potential that not even felt may have though of yet, it turns out to be a rather conservative system as it is now.

all the systems below are kinematically equivalent (as for drivetrain issues, not for braking)

A



B



C



D



cheers, hannes

[UP Dude]

Originally Posted by _dw

There is no "feedback loop", no magic voodoo, and certainly no religious intervention.

I heard the Catholic church is working on their own suspension for next year. Dubbed the "JC Link", it is supposed to not only float over terrain, but it can also ride on water. It will redefine "all mountain".

It's gonna be sweet.

[igorion]

oh, i even had my original four bar tool adapted to play around with the system...

[jeffscott]

I dont quite get it yet. How does it compare to the Rocky ETSX.

[Mr.P]

Originally Posted by rigel

First to hear about equilink or your impressions of it? I saw and read about equilink months ago , and thought, "Boy, Dave Weagle is going to be a rich man with all these copy cats..."

Yea. It seems to be a variation of the DW link - just without the final "kick" in the stroke.

I didn't see any carbon bendy bits, as there was too much marketing speak on the website that turned me off from reading. But Trek did try carbon flexy bits on their Fuel and 5" bike lines. It seemed to work ok for short travel, but it was no substitute for a pivot at 5". Cannondale tried carbon flex chain stays too. Neither design continues, except maybe the Fuel.

P

[ferday]

Dave Weagle is going to be a rich man with all these copy cats...

the equilink will be nice competition for the dw, the vpp, and the maestro (and all the others in between...)

[wyrm]

What do you think of the braking performance? Would the E-link also neutralize the squat and almost lock up... causing brk jack?

[chad1433]

It looks interesting. It also looks limitless in it's travel abilities. Changing rockers would effect longer travel, so it seems like if they do well with this model, they could have many other bikes in the future.

Looks a bit like a reverse VPP to me.

[derby]

I think (at least I hope!) Steve was being cynical or in the spirit of tongue-in-cheek in humor in his original post about the Felt 4 bar

The Felt rear stays would flex slightly during travel introducing a modification of the axle path and spring rate. The flex tension changes may alter the ride time experience from expected relative effects of path and shock relation to inertia analysis.

The Felt web site seems to be infected with a similar strain of delusional fuzzy physics as Ellsworth's patented mistakes about ICT.

[Steve from JH]

Hannes, am I wrong in stating that one gear combination and suspension position could have !00% anti-squat and 0 pedal feedback instantaneously?

I don't think that combination can be achieved with conventional single pivot or 4-bar systems.

[Ridge Rider]

Originally Posted by Steve from JH

I first heard about this a week or so ago:

http://www.feltequilink.com/

Since then, when not riding my bike, I've been thinking about this design. I've decided it's probably the real thing.

What you have is something that looks like a D-W link but with an extra vertical link connecting the rocker and bottom links. The seat stay and chain stay are carbon and are not connected vertically, so you have a "V" instead of a triangle. The carbon is designed to flex vertically but not horizontally. In fact it has to flex in order for the linkage to move because the rear pivots get farther apart in compression and closer together in extension.

The result is an axle path that is close to a vertical straight line. This means the axle path perpendicular is approximately a horizontal line throughout travel, as though you had a very distant fixed pivot at about the height of the axle.

The advantages would be very low pedal feedback and a highly active suspension. Braking would be like with a parallel floater that always stayed parallel to the ground, making it even more neutral than a real floater. This gives traction advantages. There would also be traction advantages when pedaling, since the loss of thrusting force at the ground would not cause suspension movement.

If it were not for the equilink itself, this kind of axle path would produce very little anti-squat, compared with, say, a D-W link. The bike would tend to squat in the rear with every pedal stroke. But the equilink changes that. Its connecting pivots can be placed to give a leverage bias in favor of extension from the force of the chain tension pulling the axle and BB together. This means that a good amount of anti-squat unrelated to the chain angle can be tuned into the suspension, without producing pedal feedback. You could set it up so that in a middle range gear, at sag, the bike had 100% anti-squat and zero pedal feedback. It would develop some feedback with compression travel, but it would still be very low.

No other design, except for URT's, can claim this. And URT's have all kinds of other problems and have been abandoned as a design.

Unless there is some unforeseen problem, I predict you'll be hearing a lot about this design in the future.

Remember, you heard it here first.

I am having a hard time understanding how the system works. The equilink is connected to 2 rotating links that are not parallel. As they rotate it seems that the distance between the end pivots of the equilink will change. Does the equilink flex? I looked at one up close recently at the Trans Rockies race but still didn't understand it. Please enlighten me on this aspect.

[wyrm]

AWWW I found the problem...... E type frt derailler...............

[endurowanker]

all that really matters is wheel path. anti-swat angle is all about changing wheel path. the claim of "near vertical wheel path" remidns me of specialized's claim on FSR. actually ended up being a less vertical wheel path than a single pivot faux bar. not necessarily a bad thing. in fact a vertical wheel path would actually have more chain growth than FSR.

this thing doesn't appear to be able to counter out sloppy pedaling any better than FSR, DW, or faux bar.


i think it's just a game of millimeters at this point. I'm gonna stick wiht what i feel are the most proven and rugged designs. namely FSR and faux bar. probably goin with a faux bar turner next time around.

i'm not saying this thing is bad, i just don't think it's a revolution.

[856er]

Here's some more info

http://www.bikemagic.com/news/articl...=&v=2&UAN=4855

[856er]

Some more info

http://www.bikemagic.com/news/articl...=&v=2&UAN=4855

[856er]

Some more info

http://www.bikemagic.com/news/articl...=&v=2&UAN=4855

[Steve from JH]

Originally Posted by derby

I think (at least I hope!) Steve was being cynical or in the spirit of tongue-in-cheek in humor in his original post about the Felt 4 bar

The Felt rear stays would flex slightly during travel introducing a modification of the axle path and spring rate. The flex tension changes may alter the ride time experience from expected relative effects of path and shock relation to inertia analysis.

The Felt web site seems to be infected with a similar strain of delusional fuzzy physics as Ellsworth's patented mistakes about ICT.

No tongue in cheek, except for "Remember, you saw it here first." Obviously, if you didn't see it here first, you can't remember that (unless you have false memories).

[UP Dude]

Originally Posted by endurowanker

all that really matters is wheel path. anti-swat angle is all about changing wheel path. the claim of "near vertical wheel path" remidns me of specialized's claim on FSR. actually ended up being a less vertical wheel path than a single pivot faux bar. not necessarily a bad thing. in fact a vertical wheel path would actually have more chain growth than FSR.

this thing doesn't appear to be able to counter out sloppy pedaling any better than FSR, DW, or faux bar.


i think it's just a game of millimeters at this point. I'm gonna stick wiht what i feel are the most proven and rugged designs. namely FSR and faux bar. probably goin with a faux bar turner next time around.

i'm not saying this thing is bad, i just don't think it's a revolution.

I agree. I was thinking this was a pure vertical wheelpath. But "near vertical" is nothing new. I'm gonna have to maintain that at this point, its going to be pretty darn hard to revolutionize suspension. Endurowanker is right, its a game of millimeters at this point. Between FSR, ICT, DW and VPP, how much better can it get? And more importantly, is it worth all of the development and patent costs to do it?

I don't think so. We're at a point where all designs perform very well, and each has their advantages and disadvantages depending on what the consumer wants. This is where style and creativity is frame design take over. Think Ibis and DW. If developing a new suspension that doesn't really do anything significantly better counts as creative style, I would think there are probably better ways to spend that money. But if you can sell it and justify the costs, I guess that is the bottom line.

And maybe I'm dead wrong. Maybe the absolutely perfect suspension has yet to be developed. Maybe it has a completely different form we haven't seen yet, does things we didn't imagine a bike would be allowed to do. That's what makes engineering fun.

Sorry, got sidetracked there. Bikes are cool

[UP Dude]

Originally Posted by 856er

Some more info

http://www.bikemagic.com/news/articl...=&v=2&UAN=4855

Interesting comment in this article that contradicts what I just said.

"It was just biding its time, though. As Felt's Director of Product Development Brian Wilson explained, "We didn't want to just do something that someone else had done - it had to be our design". That's not just a matter of corporate ego - these days you've pretty much got to have your own suspension design to acheive any sort of brand credibility. Specialized has FSR, Marin has Quad-Link, Giant has Maestro and now Felt has Equilink."

I guess everyone does has to have their own design.

[SCUBAPRO]

Originally Posted by Steve from JH

DT should license and build some of these:

http://forums.mtbr.com/showthread.ph...59#post2178859

Looks like a DW with a "red band aid". I think the "red cross-brace" might get in the way of the tire so you'll need to extend the chainstay to compensate. Also, the suspension would be less compliant when pedaling due to the cross brace pulling down on the rocker.

[Dusty Bottoms]

The techology description actually contradicts itself:

"As you pedal, the red link automatically pulls down on the upper horizontal link, which instantly negates and equalizes weight transfer."

vs.

"By keeping the drivetrain independent of the suspension, it is allowed to perform the job it was solely intended: to propel the bicycle and rider forward."

IT IS IMPOSSIBLE TO KEEP THE DRIVETRAIN INDEPENDENT OF THE SUSPENSION IF THE RED LINK PULLS ON THE HORIZONTAL LINK AS YOU PEDAL!

You also notice they don't say a damn word about braking preformance. This design smells a lot like vpp.

After a month on a Horst 5 Spot, I can say I like how the design tracks, and it lands medium airs VERY smoothly. However, it still suffers from brake induced suspension lockout, just like every full suspension design I've ever ridden.

[mbmojo]

Sure does have a lot of bolts, bushings and/or bearings though.

[Ridge Rider]

The equilink is connected to 2 rotating links that are not parallel. Won't the distance between the end pivots of the equilink change as the 2 links rotate? Can someone explain this to me.

[SCUBAPRO]

Originally Posted by Dusty Bottoms

IT IS IMPOSSIBLE TO KEEP THE DRIVETRAIN INDEPENDENT OF THE SUSPENSION IF THE RED LINK PULLS ON THE HORIZONTAL LINK AS YOU PEDAL!

I agree!!! Until you stop pedaling then the suspension becomes independent of the drivetrain

[Steve from JH]

Originally Posted by Ridge Rider

The equilink is connected to 2 rotating links that are not parallel. Won't the distance between the end pivots of the equilink change as the 2 links rotate? Can someone explain this to me.

The equilink controls the movement of the rocker and lower link. The rear stays are carbon and must flex because the two rear pivots change in their distance from one another.

Since the rear assembly is not a rigid body, we can consider the chain force translated to the axle as acting separately on the upper and lower links. The pivots of the equilink and the angles of the upper and lower links are designed to give more leverage to the lower link, rotating it forward and causing extension. This extension is designed to balance exactly the compressing force from rearward load transfer from acceleration, in at least one gear combo. The thrusting force from the ground, translated to the axle, produces negligible anti-squat because the axle normal line is very close to horizontal all the way through travel. You could get this 100% anti-squat condition in a gear that had a chain line parallel to the axle normal--thus 0 pedal feedback, at least initially.

[Bortis Yelltzen]

First thing I would do is ride the bike up a rough climb and back down. Then remove the red "Equilink" and do it again. I would be suprised if other than a small amount of flex there is any difference at all. But I would need to ride it to make an offical call.

Based on visual analysis I call BS.

The two links are already fixed together by the rear triangle, so I don't see how adding this extra link changes anything. If you take that link out all you have is a DW-Link/Maestro type design from what I can tell. All I can see is the rear triangle has no brace closest to the seat stay like a DW-Link and VPP bike has, the Felt has a "V" shaped rear triangle where DW/VPP has a closed triangluated rear triangle. Felt then moved/added a "5th" link tying the links together, which in my mind does the same thing a stiff triangulated rear triangle does. The downward angle of the lower pivot link is what is causing chain tension to pull the rear wheel forward (extending the suspension) when pedaling load is applied to reduce squat, the red link is a distraction. The geometry of the two links is what is controlling the wheel path, the red link has nothing to do with that either. And the link driving the shock rotates the same direction as the lower link, therefore it will not function like VPP in terms of wheel path. Now if the "V" shape of the rear triangle is designed to flex and open up and close during extension and contraction of the suspension I could see this little red link might have some effect, but I'm not convinced. I would like to see an animation of some sorts explaining things better, my sketches and free body diagrams are just telling me it is all marketing.

Looks like clever marketing and a way to circumvent the DW-Link and VPP patents by making new claims, even if they are fless than real.

My $0.02

B