Constant trail suspension fork?- Mtbr.com
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  1. #1
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    Constant trail suspension fork?

    https://www.pinkbike.com/news/trust-...kage-fork.html

    I'm curious to hear people's thoughts (not about the price or the look, which are both outrageous in different ways) about this concept.

    At first I thought "man, anti-dive, constant trail, awesome!"

    Then on my ride yesterday I thought about it a bit more as I braked into corners and I'm less sure - because I realized that in general, if I'm hard on the front brake (causing some amount of dive/lower steering trail) I'm about to do a tight corner of some kind - and that the lower trail in that situation is actually beneficial. I'm not sure I'd want to rail into a tight turn and be stuck with 110mm of steering trail, when (with some compression at the front end) I could have 80-90mm.

    If the trail was *nothing* but tight turns, after all, I'd want a bike with much lower trail to begin with. On more open/flowy cornering where I'm not on the brakes much I want to keep the higher trail, and the dive isn't an issue anyway.

    But I haven't thought about it much (let alone ridden the fork, though I have ridden old Amps and Proflexs back in the day). Anyone got any clever insights?

    -Walt

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    I am not a suspension or bike engineer but I am thinking constant wheelbase would be better than constant trail, this would allow constant weight distribution but have a change in steering feel over the travel. Not sure if the suspension performance of a forward axle path in the for would be horrible or not.

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    http://forums.mtbr.com/general-discu...e-1053001.html

    https://structure.bike/

    There is info in here to dig into it more. Same concept.

  4. #4
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    Yeah, I've seen that one (and the German A fork, and the Fournales, etc) they're making the same claim - that front end fork dive/reduced steering trail is something we want to eliminate. I'm actually somewhat convinced that having some dive and lowering trail when you're on the front brake is *desirable*, though, at least in most situations you'll encounter on a mountain bike.

    -Walt

  5. #5
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    bit of ride report here...

    seems the traction element is noticeably good... I guess the reported lack of stiction would do that...potentially.

    as for constant trail..... that's an interesting thought.... i'm pretty curious about it. you hardly ever see anything DW has to do with getting slated so that gets it's toe in the door, id say....

    also the fact it looks, well, not *bad* given its a linkage fork with trailing axle that alone deserves some kudos...

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    Anyone done some math on how much steering trail they are eliminating?

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    Yeah, so Weigle says:
    “On every telescopic fork, when you come into a corner, you want stability. But what happens is that you weight the front of the bike, the fork dives, you get less mechanical trail, and the bike gets less stable. We humans have learned, over 120 years of riding telescopic forks, to just deal with it. The brain is good at just making it work."

    I don't see the logic, though. I don't want MORE stability when I'm trying to get the bike to lean over and turn - I want *less*. I'd never build a bike for super tight twisty trails with 150mm of steering trail. Or am I crazy?

    -Walt

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    From here. https://gearjunkie.com/trust-perform...ont-suspension

    Flexibility in a stanchion fork reduces initiation force. But it also increases instability, which makes it harder for a rider to ream corners and pop over larger obstacles. “On modern bikes, larger wheels, bigger tires, and slacker head angles reduce that instability, but you can still feel it,” said Weagle. “And in order for a front suspension fork to absorb shock in both small and large bumps can require Ph.D.-level tuning skills, and even then you’re not always able to achieve perfection.”

    So basically the long slack low 29'ers that many of us are moving towards negate what they've got going on. Oh and I have no Ph.D but damn modern forks feel good with just a few twiddles of the dials.

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    What is "reaming" a corner?

    As much as I hate to say it, a lot of the explanation for this just sounds like marketing gibberish to me. They seem to be claiming that high trail numbers are good for cornering, which is sort of the opposite of how I understand steering trail (lots of steering trail makes the bike want to go straight, not corner).

    -Walt

  10. #10
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    Quote Originally Posted by Walt View Post
    Yeah, so Weigle says:
    “On every telescopic fork, when you come into a corner, you want stability. But what happens is that you weight the front of the bike, the fork dives, you get less mechanical trail, and the bike gets less stable. We humans have learned, over 120 years of riding telescopic forks, to just deal with it. The brain is good at just making it work."
    -Walt
    Seems to me that if this is such a fantastic idea it might have been developed for motorcycles. Dirt or road racing. I certainly think these guys are looking for every edge. Rear suspension is difference because of pedaling forces vs an engine, but I would think on the front these would have been tried. We know nearly all motorcycles have traditional telescopic forks.
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  11. #11
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    been thinking this over....I really like riding rigid bikes (as in no suspension). how much of that is knowing where I am in relation to the front wheel with one less dynamic element (ie no suspension movement thus no change in trail) I don't know. I don't find the steering in corners to be detrimental when I go back to a suspension fork and I can go a shed load faster with it....but in slow tech sections I still have a love of full rigid....hmmm! interesting!

  12. #12
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    BMW made (maybe still makes?) some linkage forked street/touring motorcycles. I have ridden them a few times and found the lack of any dive to be really disconcerting - but I'm almost completely incompetent at riding a motorcycle fast on pavement (on dirt I'm only sort of incompetent) so I'm not sure my opinion matters much there.

    Telescoping forks are certainly standard on all forms of 2-wheeled race moto that I can think of. That's not necessarily the end of the argument, though. Lots of things about bikes are different than motorcycles.

    -Walt

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    I'm really excited about this and i hope they sell a heap of them. It's possible that it's ideal to have the axle path in line with the steering axis, but it seems unlikely. It's impossible to really explore the idea without lots of people riding and designing linkage forks though.

    Quote Originally Posted by Walt View Post
    What is "reaming" a corner?

    As much as I hate to say it, a lot of the explanation for this just sounds like marketing gibberish to me. They seem to be claiming that high trail numbers are good for cornering, which is sort of the opposite of how I understand steering trail (lots of steering trail makes the bike want to go straight, not corner).

    -Walt
    That's not how i understand it. My understanding is that high trail makes the bike resistant to altering it's line, be that going straight or cornering. Once it's leaned in to a turn a high trail bike is going to be less sensitive to what pushes the wheel, be that the handlebars or obstacles the bike is rolling over.

    High trail feels sluggish cuz the bike needs to be tipped over more to corner.
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    That's a good point, but I still don't want the high trail when I'm initiating the turn (that's where I'm most likely to lose traction/miss the corner). To me the initial lean-in is the crucial stage and once you've got yourself established at the lean angle you need, you're good.

    To be fair, too, any amount of trail is going to make the bike want to go back to straight - not maintain a lean and keep cornering. More trail is going to mean the bike tries harder to go back to straight. You can feel this in a corner on a DH bike vs XC pretty easily - it takes way more effort/weight shift to ride the same radius turn on the higher trail bike. Steering trail literally just tries to keep the wheels lined up with each other - not maintain a turn.

    Regardless, I'm also excited to see how it rides (assuming I ever get a chance, since I'm sure as heck not going to drop even half of that price on a fork).

    -Walt

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    Quote Originally Posted by Walt View Post
    You can feel this in a corner on a DH bike vs XC pretty easily - it takes way more effort/weight shift to ride the same radius turn on the higher trail bike. Steering trail literally just tries to keep the wheels lined up with each other - not maintain a turn.

    Regardless, I'm also excited to see how it rides (assuming I ever get a chance, since I'm sure as heck not going to drop even half of that price on a fork).

    -Walt
    I've always thought that was because of a longer wheelbase and a more rearward weight distribution. Once you get the bike tipped over and your weight in the right spot it doesn't seem that different.

    When you have tight pedally flat trails you can run in to problems where you can't tip a high trail bike enough to maintain balance and cut a tight enough turn. Feels crappy and clumsy. Knowing your typical riding, i wonder if that's what you're experiencing?

    I like high trail for entering corners, you can just slam the bike in there rather than having to feel out the traction.
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  16. #16
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    Quote Originally Posted by scottzg View Post
    I've always thought that was because of a longer wheelbase and a more rearward weight distribution. Once you get the bike tipped over and your weight in the right spot it doesn't seem that different.

    When you have tight pedally flat trails you can run in to problems where you can't tip a high trail bike enough to maintain balance and cut a tight enough turn. Feels crappy and clumsy. Knowing your typical riding, i wonder if that's what you're experiencing?

    I like high trail for entering corners, you can just slam the bike in there rather than having to feel out the traction.
    I've experimented with bikes with same wheelbase/different trail. You just have to remember - trail is trying to center the front wheel contact patch behind the steering axis. It is a self-centering feature. More of it means more effort to both initiate and maintain a turn, and there's no free lunch - more trail will require more effort to turn and in general be more "sluggish".

    -Walt

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    I'm looking at this development from a different angle. I want a fork I can put panniers on where the loaded gear is considered sprung mass. This is one way.

    I have some CAD stuff of my own thoughts, but, frankly, Trust's work is superior to my own. Mine is packaged differently and is oriented around racks and full fenders, and the kinematics works out of those packaging concerns has an effect on needing the travel limited to 110mm. Any further and the trail and anti-dive conditions get weird (and dangerous in the case of 100%+ anti dive). Trust is interesting in the sense that they have squeezed much more travel out of the approach in a compact build envelope.

    Good on them, I say. I will agree that there's a lot to unpack in terms of marketing, and these units just need to see a lot of ride time. If anything I'm glad of their presence because it will boost the acceptability of my future works.

    I don't like the internal shocks though. I would be happy with a single external rear suspension shock. I get the reasoning (the 1:1 rider weight to shock pressure is enticing), I just dislike it because of the economic result.
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  18. #18
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    Quote Originally Posted by Walt View Post
    I've experimented with bikes with same wheelbase/different trail. You just have to remember - trail is trying to center the front wheel contact patch behind the steering axis. It is a self-centering feature. More of it means more effort to both initiate and maintain a turn, and there's no free lunch - more trail will require more effort to turn and in general be more "sluggish".

    -Walt
    I don't doubt you, but i've never experienced it as a 'self centering feature,' although i've never experienced trail change in isolation except on road bikes. I agree with more effort to turn and more sluggish, but i equated that to being that with more trail you have to 'lift' the bike higher for the same change in turning radius. (i'm out of my depth in this conversation but i find it fascinating.)



    Another aspect i think is interesting is that a linkage fork can decouple brake and ground forces. The brakes could be used to hold the fork closer to the top of its stroke.

    Quote Originally Posted by Drew Diller View Post
    I'm looking at this development from a different angle. I want a fork I can put panniers on where the loaded gear is considered sprung mass. This is one way.

    I have some CAD stuff of my own thoughts, but, frankly, Trust's work is superior to my own. Mine is packaged differently and is oriented around racks and full fenders, and the kinematics works out of those packaging concerns has an effect on needing the travel limited to 110mm. Any further and the trail and anti-dive conditions get weird (and dangerous in the case of 100%+ anti dive). Trust is interesting in the sense that they have squeezed much more travel out of the approach in a compact build envelope.

    Good on them, I say. I will agree that there's a lot to unpack in terms of marketing, and these units just need to see a lot of ride time. If anything I'm glad of their presence because it will boost the acceptability of my future works.

    I don't like the internal shocks though. I would be happy with a single external rear suspension shock. I get the reasoning (the 1:1 rider weight to shock pressure is enticing), I just dislike it because of the economic result.
    Man i never considered this design with its implications for bikepacking, that's kinda brilliant.


    Seems like at this stage in the game they need the most aesthetically pleasing design possible, and if it requires exotic engineering, so be it. So internal through shaft shocks are pretty smart and their target audience doesn't really care about cost that much so much as that they can ride something truly revolutionary and really credible. Err, it's a smart business decision, i think.

    Can you share your work?
    Last edited by scottzg; 10-25-2018 at 11:00 PM.
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    Quote Originally Posted by scottzg View Post
    Can you share your work?
    I'll think about it, because the state of my work is disorganized and not easily digestible without certain software installed on a computer, and because I don't want to distract too much from this conversation at hand. I'll post it in a new thread if I decide to share.

    I'm not trying to be secretive, I'm trying to be easily understood and my materials specific to this topic are half baked as is.
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  20. #20
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    I'm no suspension expert, far from it. But have ridden them since buying a Manitou 1 way back in the early 90s. Having never ridden a linkage fork other than a Lauf (doesn't count really), i really am interested in riding a Trust fork but...how the heck is that going to happen with that price?! The fork won't make it for that reason alone. I thought the Rock Shox RS-1 was expensive and it seems that hasn't become too widespread...this one is $1k more that that?

    I find it mildly frustrating that none of the articles have a GIF of the fork going through its travel. I mean, what does EVERYBODY do when they see a new fork on a bike...? They grab the front brake and push down on it to see how it feels. Granted we can't feel it but seeing how different the axle moves through the travel would help me visualize it all instead of these hollow descriptions of why it's "kinda" a 130mm travel fork but not really because it's too complex for you to understand. I also don't understand only having one axle to crown for a slew of bikes that are built around much longer forks. So putting it on a frame built for a 160 fork you'll drop the BB and steepen the HTA by how much?

    I'm like dRjOn with drawing personal impressions from comparisons with rigid fork bikes. I like the consistency in geometry of rigids, that to me is the primary in "stability" -- no dive, no change in head tube angle when braking or going over a drop, you know what to expect, no change in trail is how they're calling it but i guarantee most every rider out there that has a telescoping fork doesn't know what Trail is and what it *feels* like. They do know how a bike's BB gets lower at full compression, it gets twitchier, and how it sucks to have the fork fully compressed when it *should* be in the middle of its travel soaking up whatever the ground has to offer. With a telescoping fork on a hardtail at least you can lay off the front brake and only use the rear so the fork can get all the travel. If this linkage fork can keep the steering geometry relatively consistent with the designed frame geometry then I really think it will change how people ride with a suspension fork.

    Reading James Huang's review of actually getting to ride the fork and testing it over various trail types and getting back on a telescoping fork was pretty neat to read:
    https://cyclingtips.com/2018/10/trus...e-fork-review/

    Being able to rail corners faster and with more control because the fork is adapting to the terrain...but maybe i'm totally soaking up the marketing hype. Of course i'll never buy one though.

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    Walt, how were you not invited to the test in Park City?!?!
    You could’ve crashed the party!


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    the cost thing - its expensive no doubt, but i see plenty of folk on santa cruz whatevers with enve rims on my local trails. swap the enve rims to alu at buying time and the difference in cost is *almost* gone. so, i suppose its a matter of preference for some...but it does cause a wee gulp to consider errr 1700$ more than a fox? yikes.

    i liked the look of the proto w external fox on the pinkbike article... knd of cool....in a T2 sort of way!

    i wonder how they are managing the trail/headangle thing. so as it compresses, the head tube drops towards the ground thus steepening head angle if you assume rotation around the rear axle - so are they compensating for this by decreasing err, offset? to keep trail the same? assuming no rear sus drop?

    but if ypou do factor in rear compression, the head angle wouldnt change? so is it not ideal for hardtails....?

    i cant seem to find any info clear enough on that...

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    Whit, that's interesting. I always found rigid bikes annoying because they *didn't* dive at all, so I have to shift my weight forward a lot more than on a bike with suspension. Probably mostly just a matter of feel/preference there, though.

    I agree that the "fits any travel bike!" thing is BS, and particularly unconvincing given that the whole point of the fork is to *prevent* unwanted changes in BB height/steering trail/etc.

    Not a problem for any of us here, of course, we can just build a bike around the fork if needed.

    The axle path has got to be pretty dramatically rearward to maintain trail - I'd also like to see at least a diagram of the axle path. I'm sure someone (Linkage dude?) will do that soon whether Trust wants the info out there or not.

    Given that volume (2500 units!? Damn... that's a cool $7 million they hope they can sell) I would doubt the cost will come down all that dramatically on future versions unless they bail to aluminum or something and bump up the weight a bit. But who knows.

    I'd ride it just for the experience. And hey, I have a bike with about that axle-crown on it already ready to go. You listening, DW?

    -Walt

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    Quote Originally Posted by Meriwether View Post
    With a telescoping fork on a hardtail at least you can lay off the front brake and only use the rear so the fork can get all the travel. If this linkage fork can keep the steering geometry relatively consistent with the designed frame geometry then I really think it will change how people ride with a suspension fork.
    .....
    Being able to rail corners faster and with more control because the fork is adapting to the terrain...
    This technique applies to full squishy bikes to, and a riding style I'm using more and more lately. Having also been riding since the earliest days of elastomer suspension and canti brakes, reliance on the front end for a majority of braking power (or lack thereof) became ingrained in my riding. I still have a box of the Salsa brake booster arches lying around somewhere. Anyway, my point is, rear brakes can do a lot more of the work now without losing traction, allowing me to enter corners without the preloaded brake dive associated with telescopic forks, and the bike simply behaves better and corners and tracks more predictably (stability?). For that reason alone, this new linkage fork has merit to me (I ain't getting one without a divorce). I'm still trying to wrap my head around the trail concept, like doing differential equations in my head, on a train headed East from Chicago at 80 mph, etc. etc., but I do know that in no way does front end dive benefit me in any way whatsoever when it comes to cornering or control.
    I would advise not taking my advice.

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    I'll admit right now, did not read all replies, but my thoughts on this topic are this....I love my rigid for one main reason, I know, consistently how it will react in any given situation because the angles etc will remain the same, no sagging, no diving, so I don't have to be concentrating as much on entering a tight corner if the fork is diving, has dived enough to quicken up the handling to me desired amount. So, having that ability on a suspension fork, where trail and WB remain constant, would eliminate the steepening of the HTA on super steep stuff where the front would usually compress and cause issues. Those are my thoughts on it, as to if I'd use one, not sure, would have to get a test ride first to see how it felt.
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    I was wondering a few things about this fork. It's an interesting idea, I have no idea how it would feel.

    Here's my question- with creating an ideal axle path for the front axle, wouldn't it be different on different head tube angles? Could you use the same fork on a bike with a 69d HTA and a 64 HTA? Again, no idea, but this one popped into my head . . .

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    Quote Originally Posted by ru-tang View Post
    I was wondering a few things about this fork. It's an interesting idea, I have no idea how it would feel.

    Here's my question- with creating an ideal axle path for the front axle, wouldn't it be different on different head tube angles? Could you use the same fork on a bike with a 69d HTA and a 64 HTA? Again, no idea, but this one popped into my head . . .
    The fork must have a given offset just like any other fork (I don't know what that is) but the main difference being as the HTA changes with the fork compressing, the offset would change as well keeping the mechanical trail constant.
    So if you start with a 69 deg HTA and 51mm offset, as the fork compresses and the HTA becomes steeper to say 72 deg but the axle path they engineered into this thing decreases fork offset so mechanical trail would stay the same keeping the "stability" of the steering constant.

    I don't know how this feels in reality and if with the steeper HTA the bike would feel as stable as the uncompressed fork with a slacker HTA. This is kinda the crux of the issue. It's not that the fork keeps the HTA from steepening but it supposedly keeps the feel of the steering consistent throughout the forks travel. Like Walt and many other builder's i've experimented with adjustable rake *rigid* forks but nothing that adjusts the rake while you're riding.

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    *thats* what I am interested in - because id guess its designed for full suspension - where I would think the steepening effect of the head angle would be much less - (no idea on the definition of 'much' here - maybe a small amount of ° ) ----but im interested enough to try and find out....

    so - on full suspension bikes, the whole chassis drops towards the ground as the suspension compresses, rather than just the front. but for a hardtail....you guys (merimether/walt) have made some long travel forked hardtails.... https://www.peterverdone.com/wiki/in...pension_Travel suggests head angle on a 140mm travel fork could vary by 7° if i'm reading it right and Mr Verdone's numbers are right....which is pretty big, with mechanical trail ranging from 90 to 50mm - albeit for a 26" wheel.

    I haven't sat and worked out the numbers specifically, for a bigger wheel diameter, but on a hardtail the trail might change as much as double that on a full suspension I reckon, so the fork you would assume would compensate for around 20mm of trail....ie on a hardtail, you are still going to get some significant trail change but less than on a telescoping fork.

    is 20mm trail that noticeable? it seems on bikes that some numbers make a big difference and some don't- in this case im guessing 20mm trail change would be pretty noticeable and so there may still be benefit of this type of fork for a non full suspension bike *if* the premise that constant trail is a good thing is valid.

    ugh. my brain hurts.

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    Quote Originally Posted by Walt View Post
    BMW made (maybe still makes?) some linkage forked street/touring motorcycles. I have ridden them a few times and found the lack of any dive to be really disconcerting - but I'm almost completely incompetent at riding a motorcycle fast on pavement (on dirt I'm only sort of incompetent) so I'm not sure my opinion matters much there.

    Telescoping forks are certainly standard on all forms of 2-wheeled race moto that I can think of. That's not necessarily the end of the argument, though. Lots of things about bikes are different than motorcycles.

    -Walt
    A bit of a tangent here but...

    https://www.cycleworld.com/why-do-al...-fork-prevails

    I suspect that a lot of the reason for race bikes not using linkage front-ends is fear of commercial failure. "Win on Sunday, sell on Monday" works the other way round if your bike is a dismal failure, even if it's because it only needs some development, especially if it looks weird. IIRC there was also some experimentation with using front brake-line pressure to adjust the compression damping on front forks to prevent dive under braking but that doesn't seem to have lasted either.

    I'd be interested to see PVD's opinion on linkage forks, both for MTBs and motorbikes.

    At the end of the day, if the brain can learn to deal with the decrease in stability under braking for a telescopic fork I'm sure it can learn to deal with the increase (or lack of decrease?) in stability provided by a linkage fork designed to provide that effect, the problem would be switching between the two and re-training the brain. As dRjOn pointed out, a rigid bike doesn't dive and people don't seem to have an issue riding those (as long as their fillings stay in!).

  30. #30
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    It's so exciting to see the concept taking off ... even if Dave's language is nearly verbatim the same as I've been using for a couple of years.

    There's so much to discuss here - let's get started!

    First, constant trail is impossible; that's a simplification. The trail cannot behave the same if the bike is compressed in heave (equally front and rear) vs. pitch (front only) - or any other scenario. Dave is probably referring to constant trail in pitch, since a telescoping fork remains constant in heave and this wouldn't be anything new. This is essentially what we've done at Structure, too - and it's so much better.

    For reference, a typical all-mountain or enduro bike has about 110 mm - 125 mm of trail at full droop (fully topped out). In full pitch, this is cut to half, at best, and an additional inch or two of front-centre is lost to fork flex. It's a huge change.

    Interestingly, we barely notice it when going from a telescoping bike to our linkage bikes because it's easy to take for granted when a machine is doing the right things, but telescoping bikes that we've been riding since childhood feel like they're trying to kill us when we switch from linkage to telescoping. The straight line motion of a telescoping fork is not as constant and predictable as we think: the bike dives on an arc and head angle, trail, and stability change in a non-linear manner, despite the linear fork motion. It's a kinematic mess, to be honest, but the human brain does a great job of adapting to a wide range of things - just look at the short, steep, and sketchy bikes we were riding 10-15 years ago! We've learned to work around the quirks of telescoping forks - and even work with the quirks to sometimes use them in our favour.

    As Walt mentioned, the "jackknife" effect of steepening head angle and decreased trail makes it easy to whip a quick turn, but it also makes the bike prone to a jackknife crash when things get too rowdy. With a bike that increases stability when compressed, you do have to be more "authoritative" when making a turn, but you still can make the same turns; it doesn't prevent you from doing what you want to do. It does, however, provide a lot more confidence in pinball situations and gives a lot more headroom before the wheel jackknifes, causing a crash.

    An alternative way to configure the bike is to use a steeper head angle to provide stability comparable to a traditional bike under rowdy conditions and vastly more agile handling when climbing. Or somewhere in between. The point is that it flips the stability situation: telescoping forked bikes are at their most stable when extended (ex. climbing) and least stable when descending or hitting things. The Trust fork or our Structure bikes are most agile when extended and most stable when compressed. We think you'll agree that's how it should be.

    A telescoping fork can only move in a straight line. If a suspension engineer could make a fork do absolutely anything, a straight line would not be the perfect choice. Straightish, perhaps, but we know from rear suspension design that nuanced changes in the motion pay big dividends in performance. The difference is even greater on the front. Linkages give us the freedom to create these nuanced changes to the motion and the ride is far better for it.

    The next step in the evolution of linkage designs would be to integrate it in to the frame, now that we don't need a straight fork that connects directly to the bar by being cantilevered all the way out at the front of the bike. Maybe some forward-thinking bike company will do that some day.
    Last edited by Structure-Ryan; 10-28-2018 at 10:10 PM.

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    Quote Originally Posted by carlhulit View Post
    I am not a suspension or bike engineer but I am thinking constant wheelbase would be better than constant trail, this would allow constant weight distribution but have a change in steering feel over the travel. Not sure if the suspension performance of a forward axle path in the for would be horrible or not.
    It certainly would! That's why most of the early linkage forks used the "J-hook" axle path in an attempt to align the axle path with bump forces. At best, this succeeded in being very "plush", but caused a decrease in trail and wheelbase, though this wasn't a huge problem with 60 mm of travel. At worst, the designers created these stability issues and forgot to consider leverage ratio and brake dive. And stiffness. And durability. And used sketchy, custom springs and dampers.


    Early designs always go through an ugly learning curve. Telescoping forks didn't nail it on the first try. I don't claim I would've done any better with a linkage design in the '90s and I appreciate all I've learned from the pioneers. Now it's time for the next generation.

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    Quote Originally Posted by LyNx View Post
    I'll admit right now, did not read all replies, but my thoughts on this topic are this....I love my rigid for one main reason, I know, consistently how it will react in any given situation because the angles etc will remain the same, no sagging, no diving, so I don't have to be concentrating as much on entering a tight corner if the fork is diving, has dived enough to quicken up the handling to me desired amount. So, having that ability on a suspension fork, where trail and WB remain constant, would eliminate the steepening of the HTA on super steep stuff where the front would usually compress and cause issues. Those are my thoughts on it, as to if I'd use one, not sure, would have to get a test ride first to see how it felt.
    It's not quite correct that wheelbase, head angle, and ride height remain constant under braking and turning loads. Depending on the configuration of the fork, let's call it about halfway between constant and what a telescoping fork would do. Definitely better, though!

    Telescoping forks add a complication: static friction (stiction). When braking, the bending moment can approach 1000 ft⋅lbs. Linear bushings are a sticky disaster under this kind of load. The resulting friction can reduce brake dive, albeit by creating an intermittently rigid fork, and the ride height drops rapidly and unpredictably when the friction breaks.

    Because our linkage moves on bearings with nearly zero friction, we add a little extra low-speed compression damping to compensate. Also, our linkage has a four position flip-chip to allow riders to tune the anti-dive vs. plushness balance. The two "middle" positions are my preferred settings, but it's a new technology and I wanted to give riders room to explore the properties; I'll probably tighten the range on subsequent models once most riders agree on the ideal balance.

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    Quote Originally Posted by dRjOn View Post
    *thats* what I am interested in - because id guess its designed for full suspension - where I would think the steepening effect of the head angle would be much less - (no idea on the definition of 'much' here - maybe a small amount of ° ) ----but im interested enough to try and find out....

    so - on full suspension bikes, the whole chassis drops towards the ground as the suspension compresses, rather than just the front. but for a hardtail....you guys (merimether/walt) have made some long travel forked hardtails.... https://www.peterverdone.com/wiki/in...pension_Travel suggests head angle on a 140mm travel fork could vary by 7° if i'm reading it right and Mr Verdone's numbers are right....which is pretty big, with mechanical trail ranging from 90 to 50mm - albeit for a 26" wheel.
    I didn't review Peter's calculation methods, but the numbers are in the right range, so the math is probably right.

    My models involve head angles around 65° - 66° and 150 mm - 160 mm of travel - typical all-mountain / enduro fare. In pitch, a telescoping fork causes head angle to steepen by around 8° and trail to reduce from around 110 mm to around half. Factor in fork flex and the wheelbase really starts to decrease.

    Trust is using huge carbon legs and our design is a monstrous carbon monocoque double-crown; you can be sure both designs manage fork flex pretty well.

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    Quote Originally Posted by Structure-Ryan View Post
    I didn't review Peter's calculation methods, but the numbers are in the right range, so the math is probably right.

    My models involve head angles around 65° - 66° and 150 mm - 160 mm of travel - typical all-mountain / enduro fare. In pitch, a telescoping fork causes head angle to steepen by around 8° and trail to reduce from around 110 mm to around half. Factor in fork flex and those numbers become a lot more dramatic, with trail going to nearly zero.

    Trust is using huge carbon legs and our design is a monstrous carbon monocoque double-crown; you can be sure both designs manage fork flex pretty well.
    I appreciate you analyzing your competitor's methods in a rational and civil way. Cheers.

    Also I like your bikes.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

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    Quote Originally Posted by Drew Diller View Post
    I appreciate you analyzing your competitor's methods in a rational and civil way. Cheers.

    Also I like your bikes.
    Thank you!

    I should mention that I badly misspoke on the fork flex effect. Haven't thought about it in months and totally botched that statement. I edited my comment to get rid of the confusing statements (for those reading carefully, this is why Drew Diller's quote is now different from my post).

    The wheelbase diminishes by an inch or two, which feels a lot like a steeper head angle, but flex doesn't decrease the trail. It does all kinds of unpleasant things, just not that.

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    Wouldn't fork flex increase trail as the axle moves backward relative to the steering axis similar to what the linkage fork is doing just in a much less controlled fashion? I haven't seen a good axle path illustration on the trust.

    Could a linkage fork simulate constant head angle during pitch compression? It looks like that is what the structure bike is doing more or less from the website.

    It is cool to see people trying new ideas even if they are not affordable for me.



    Quote Originally Posted by Structure-Ryan View Post
    Thank you!

    I should mention that I badly misspoke on the fork flex effect. Haven't thought about it in months and totally botched that statement. I edited my comment to get rid of the confusing statements (for those reading carefully, this is why Drew Diller's quote is now different from my post).

    The wheelbase diminishes by an inch or two, which feels a lot like a steeper head angle, but flex doesn't decrease the trail. It does all kinds of unpleasant things, just not that.

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    Quote Originally Posted by carlhulit View Post
    Wouldn't fork flex increase trail as the axle moves backward relative to the steering axis similar to what the linkage fork is doing just in a much less controlled fashion? I haven't seen a good axle path illustration on the trust.

    Could a linkage fork simulate constant head angle during pitch compression? It looks like that is what the structure bike is doing more or less from the website.

    It is cool to see people trying new ideas even if they are not affordable for me.
    That's correct about flex mimicking trail. It creates a weird effect because the "trail" is maximized straight fore-aft and rapidly diminishes when the wheel isn't pointed straight ahead. This creates a highly unpredictable situation; definitely not a benefit to handling, despite the increased trail.

    Yes, our design maintains a constant head angle in pitch.
    Engineer, product manager, brand manager for Structure Cycleworks.

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    Interesting discussion all around.

    I just happened to be re-listening to Ask a Founder: A Talk w/ Keith Bontrager on youtube today and came across this nugget.
    "....telescoping forks are going to win......" referring to a conversation back in mid 90's
    Segment starts at 1:07:05.
    https://www.youtube.com/watch?v=QYvPMmlBZwg

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    Quote Originally Posted by bme107 View Post
    Interesting discussion all around.

    I just happened to be re-listening to Ask a Founder: A Talk w/ Keith Bontrager on youtube today and came across this nugget.
    "....telescoping forks are going to win......" referring to a conversation back in mid 90's
    Segment starts at 1:07:05.
    https://www.youtube.com/watch?v=QYvPMmlBZwg
    I have immense respect for Keith. Legend, founding father, all around visionary.

    That said, his next statement was:

    "Same thing with rear suspension: there are all kinds of crazy ideas ... a good shock and a very simple swingarm is going to be the best way to go."

    You don't see many "very simple swingarm" rear suspension designs. We've solved the problems that worried Keith about rear suspension, reducing the drawbacks to the point that the advantages of a multi-link make it the "best way to go".

    Multi-link designs offer far greater advantages on the front, compared to telescoping forks, than multi-link vs. swingarm on the rear. Rear suspension has demonstrated it's possible and the kinematic understanding has evolved to the point that we're ready to do it. It's time.
    Engineer, product manager, brand manager for Structure Cycleworks.

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    But not at the cost of what you can get a complete carbon frame with shock for, at least IMHO, not for the slight improvements over a tele-scoping fork. That being said, getting more of these out into "the wilds" so people can actually test them is the only way to change people's minds, not a lot have $2700 to just blow on a guess.

    Quote Originally Posted by Structure-Ryan View Post
    .........Multi-link designs offer far greater advantages on the front, compared to telescoping forks, than multi-link vs. swingarm on the rear. Rear suspension has demonstrated it's possible and the kinematic understanding has evolved to the point that we're ready to do it. It's time.
    One day your life will flash before your eyes, will it be worth watching??

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    I asked the Trust folks about OE pricing and this was their reply:

    "Hi Walt –

    Thanks for your interest in Trust Performance! Due to our limited production run and the immediate response from the market, we’re scrambling a bit to keep up with demand. As such, we don’t have immediate OE plans, but plan to get there in time. Let’s keep in touch! See you on the PC trails!"

    So maybe people are buying them.

    -Walt

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    Quote Originally Posted by Walt View Post
    I asked the Trust folks about OE pricing and this was their reply:

    "Hi Walt –

    Thanks for your interest in Trust Performance! Due to our limited production run and the immediate response from the market, we’re scrambling a bit to keep up with demand. As such, we don’t have immediate OE plans, but plan to get there in time. Let’s keep in touch! See you on the PC trails!"

    So maybe people are buying them.

    -Walt
    Either that or they are just keeping things pretty low volume to 'test the waters' as it were?

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    Quote Originally Posted by Just J View Post
    Either that or they are just keeping things pretty low volume to 'test the waters' as it were?
    They supposedly have 2,500 of them in stock, though...

    -Walt

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    Quote Originally Posted by Walt View Post
    They supposedly have 2,500 of them in stock, though...

    -Walt
    You think?! Nearly 7m worth of stock is some testing of the water!

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    Perhaps another way to think if it is that you could potentially tune the trail to the conditions. By adjusting or swapping the links you could change the trail for situations as needed. So if you're here in BendOR where things are typically pretty open and flowy you could get that more stable feeling you're after but if you head to someplace with a lot of windy tight single track you could tighten things up a bit.

    No idea if that's something the Trust peeps are looking into but it would be significantly easier and hopefully cheaper than swapping trail numbers on a traditional fork.

    Quote Originally Posted by Just J View Post
    You think?! Nearly 7m worth of stock is some testing of the water!
    If you've got the bankroll, this is the best way to do it. You're launching a new widget that you think is a game changer and will disrupt the market in a big way. In order to get the best return you need to have inventory on hand when own the internet for a day. When people say "take my money" and you can't you're leaving money on the table.

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    Quote Originally Posted by customfab View Post
    If you've got the bankroll, this is the best way to do it. You're launching a new widget that you think is a game changer and will disrupt the market in a big way. In order to get the best return you need to have inventory on hand when own the internet for a day. When people say "take my money" and you can't you're leaving money on the table.
    I get that yes and I hope that there are plenty of people out there saying “take my money” to those guys. If it really is a game changer then I can’t wait to try one.

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    Crossing my fingers...

    I hope so too, but I find it disturbing that MC has gone silent on it. Usually if something is amazing he'll let you know pretty quick.

    -W

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    Who MC?

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    mikesee / Lace Mine 29 - Big Bicycle Wheels

    Done lots of stuff on a bike (understatement) and has a skill for documenting.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  50. #50
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    must admit to agreeing that MC's candour and reservation makes me want to wait this one out a bit. i nearly bought one as i believe conceptually there are some potential benefits to hardtails.

    however a thread on the shock forum mentioned something interesting. the axle is the only connection L-R, and it is relatively small.

    so how do you get parallel movement - is it due to settings being so low or maybe high that the difference is hard to discern? some clever trick? or do you just have to be asolutely critically accurate in shock set up?

    dont know. still interested tho'

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    MC looks like he was involved with a big Outside mag multi-bike review extravaganza. Perhaps that put a damper on his continued public conversations about this fork.

    My take is much the same as many here: I want to ride it, the marketing is suspect (replace a 160mm 36?), the price is a deal breaker for me, and I am also confused by the dual air spring/single damper set up. If is it stiff enough, why not the more common spring in one leg, damper in the other?

    Much like the Elkat Eskar I reviewed recently with a not-final shock tune, I am willing to give DW more leeway than most people in the industry when it comes to bold claims of revolutionary performance.

  52. #52
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    Meah, not sure I'll believe anyone that's starting up has that much stock, but whatever, play it like it's already a success and it will be

    As to MikeC, if you look at the pic he posted of the test bikes, you'll notice that the very front one looks to be running one of these forks, so I'm guessing he's going to have some thoughts on them and if it's all a lot of marketing or if it actually works as advertised.

    One day your life will flash before your eyes, will it be worth watching??

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    https://lacemine29.blogspot.com/2018...rk-review.html

    I'm bummed to read this. For me, it drives home that linkage/spring/damper/rider/geometry/terrain... they're all interconnected. Make stupid claims, win stupid prizes.

    (i recently mounted up the flexiest fork i've run in many years... but the damper is sublime, and it doesn't lock up under heavy braking or squirm under g-outs. Do i care about flex? I thought i knew, but i don't know.)
    "Things that are complex are not useful, Things that are useful are simple."
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    Apparently DW should stick to suspension layout rather than damper design...

    It's a bummer that the damper completely prevented any observation of the primary design goal of stability throughout fork travel.

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    Wow, post/review pulled already. Someone out there must be pretty pissed...

    -Walt

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    Quote Originally Posted by Walt View Post
    Wow, post/review pulled already. Someone out there must be pretty pissed...

    -Walt
    Oops! Glad I read that last night and also glad I didn’t ask you to get one for me!

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    Quote Originally Posted by Walt View Post
    Wow, post/review pulled already. Someone out there must be pretty pissed...

    -Walt
    Looks like it's still there...?

    https://lacemine29.blogspot.com/

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    Interesting read. Looks like the fork itself works, its just the damping that was too harsh and Trust didn't seem to think outside of their own dyno tests. Maybe they should have done a butt dyno along with the machine dyno.

  59. #59
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    Constant trail suspension fork?

    Quote Originally Posted by snox700 View Post
    Looks like it's still there...?

    https://lacemine29.blogspot.com/
    I get the impression that Mike’s write up has gone a little viral as I’ve just had a friend of mine who doesn’t frequent this site, randomly talk to me about it. Possibly why some people were struggling to get on the site as the traffic might have been larger than the site is used to seeing? Bad news if you are Trust.

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    Huh, now I see it. Got a 404 trying to look at it earlier this morning.

    Wow, that's a really bad review. It's pretty much what I expected after the updates suddenly stopped, but I'm still a little bummed. I have no interest in a $2700 fork, but I was hoping to see the idea trickle down in a few years to a cost I could stomach.

    I trust MC pretty implicitly as I've known him for a long time and have even built some stuff for him (including stuff he didn't like and let me know about) so if he doesn't like it, it probably sucks.

    Bummer.

    -Walt

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    I'm a bit disappointed Trust would express that level of arrogance towards another expert in the industry. If you're hitting a hard-stop at 80% travel with no air in the chambers, there's a technical issue; if 7 people have reported the fork feels overdamped -on a design that extremely over-leverages the shock and damper- there's a technical issue. The comment about the unusably short steerer makes one wonder if Trust even checked out the same fork (insert whatever conspiracy here). But regardless, is there any courtesy in saying, "man, we can't replicate what you've described but we believed you experienced it. Can we send you a different fork...give it another shot?"

  62. #62
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    Quote Originally Posted by Just J View Post
    Possibly why some people were struggling to get on the site as the traffic might have been larger than the site is used to seeing?
    Nah, the first link posted is busted, that's all.

  63. #63
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    Quote Originally Posted by dr.welby View Post
    Nah, the first link posted is busted, that's all.
    I clicked on the link Mike posted yesterday just after Walt mentioned it being taken down, it wasn’t working for me at that point but it was yesterday. Either way, it seems to be ok now.

  64. #64
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    Don't understand why you're shocked, maybe I just have a different view of most engineers, but sounds about right to me - design something relying strictly on the numbers and computer testing, ignore real world feedback that says contrary to what your "numbers" tell you, think that everyone else isn't as smart as you and must not know what they're doing and messed up in setting up/using said product=engineer

    Quote Originally Posted by VegasSingleSpeed View Post
    I'm a bit disappointed Trust would express that level of arrogance towards another expert in the industry. If you're hitting a hard-stop at 80% travel with no air in the chambers, there's a technical issue; if 7 people have reported the fork feels overdamped -on a design that extremely over-leverages the shock and damper- there's a technical issue. The comment about the unusably short steerer makes one wonder if Trust even checked out the same fork (insert whatever conspiracy here). But regardless, is there any courtesy in saying, "man, we can't replicate what you've described but we believed you experienced it. Can we send you a different fork...give it another shot?"
    One day your life will flash before your eyes, will it be worth watching??

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    Another old man's $.02 regarding the Trust fork

    Quickie Trust fork review after a shakedown ride at Skyline (Napa). The Trust fork was a demo from my LBS in Boise (Bauerhaus Bikes) so I left the steerer uncut and did not modify the air spring or damper in anyway (which is usually my first step when getting any new fork). The bike I used for the test is a small Evil Calling (130mm bike) with a 150mm Pike RCT3 that had a lighter oil in the damper and an ACS3 coil.

    Setup:
    Do not follow the recommended air pressure for each leg. It's too high. I started with 130psi (body weight) but settled on 110 psi for each leg.
    The sag meter is basically useless. Set the fork based on feel instead of sag.
    I used the recommended rebound and compression settings based on weight.
    Putting a wheel in requires a little bit of patience. It's not as intuitive as a regular telescopic fork.
    Skip the parking lot bounce test. It will feel over-damped and harsh.
    The Trust weighs about 4.6 lbs with axle and uncut steerer. Almost exactly the same as the Pike with the ACS3.
    The front brake guides are simple and elegant.

    Riding:
    Surprisingly, the fork is plush in the trail and open mode over trail chatter.
    It's not as linear on the big hits as the 150mm Pike with ACS3 that was on the bike before. I think I can remove additional tokens from the air spring to make it more linear but since this is not my fork, I did no dare modify it in any way.
    The fork was very rigid. I climb quite a bit standing up and the fork was rock solid (granted, I weigh 130-135 lbs).
    It was a little bit harder to launch the front end on lips, rocks but I think that is just a matter of adjusting my timing.
    On fast, chunky downhills, the Trust absorbed the fast hits pretty well but it also ramped up too quickly. Removing the tokens would've helped make it more linear. This is the same problem I have with every air sprung fork which is why I've converted all my forks to coil.

    Verdict:
    I give this fork a 2 thumbs up. I think it makes a great trail fork (not that I would replace my 36, Pike or Lyrik with it). Things that can be improved are:
    Better guides for wheel installation
    Coil option.
    Working sag indicator.
    Greater LSC adjustment range.
    Affordability.

    Did I mention that the fork is so ugly that it's beautiful?Constant trail suspension fork?-2176842f-4d49-44e2-b0ee-c8e33c903528.jpgConstant trail suspension fork?-7ae6de05-9ce5-4050-968f-c0d68ddc6744.jpgConstant trail suspension fork?-calling-trust-fork.jpg

  66. #66
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    Call me skeptical, but all of a sudden after a not glowing review of this fork by 7 different riders is released, there is this glowing review by one guy, with no interaction with this thread until after the bad review, who also happens to own an Evil
    One day your life will flash before your eyes, will it be worth watching??

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    Quote Originally Posted by LyNx View Post
    Call me skeptical, but all of a sudden after a not glowing review of this fork by 7 different riders is released, there is this glowing review by one guy, with no interaction with this thread until after the bad review, who also happens to own an Evil
    I'm not sure I would call my review "glowing". But it is from someone, that pays for his own stuff, that has no brand loyalty and has ridden the Trust fork for its intended purpose. While I do like Evil bikes, the last bike I bought this year is a Knolly Warden Carbon.

  68. #68
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    I think a review that says this wouldn't be a positive replacement for forks that cost 1/3 of what the Trust does isn't exactly "glowing" either. To me that's pretty far from "2 thumbs up" (ie, "this is awesome, go buy it"), but whatever.

    IMO, this review basically confirms a lot of what MC said (spring rate issues, damping issues, travel indicator doesn't work, etc). The more info we get the better, right?

    I think the best case here is that the problem is the damper, which is *relatively* easy to fix (though maybe expensive enough given the money already dumped into the project that it'll kill the company). The worst case is that the whole concept is somehow flawed.

    Based on the reviews so far, I'd probably hesitate to pay $500 for this fork, let alone $2700. But I wish them the best of luck with it.

    -Walt

  69. #69
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    Quote Originally Posted by Walt View Post
    I think a review that says this wouldn't be a positive replacement for forks that cost 1/3 of what the Trust does isn't exactly "glowing" either. To me that's pretty far from "2 thumbs up" (ie, "this is awesome, go buy it"), but whatever.

    IMO, this review basically confirms a lot of what MC said (spring rate issues, damping issues, travel indicator doesn't work, etc). The more info we get the better, right?

    I think the best case here is that the problem is the damper, which is *relatively* easy to fix (though maybe expensive enough given the money already dumped into the project that it'll kill the company). The worst case is that the whole concept is somehow flawed.

    Based on the reviews so far, I'd probably hesitate to pay $500 for this fork, let alone $2700. But I wish them the best of luck with it.

    -Walt
    While I would not pay $2.7k for a Trust (or $1k for that matter), I would gladly trade one of my Pike's for the Trust simply for the opportunity to open it up and tinker with the air spring and damper to see if I can customize it for my weight/riding style. I do like the chassis and the suspension action but I think there can be a massive improvement in the feel of the fork if the spring and damper can be customized.

  70. #70
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    Yeah, I don't know how much aftermarket tuning is possible here, but I'd assume it can be done with enough time/money/determination. And really, a fork this expensive should really be tunable out of the box for even extremely picky riders.

    But yeah, I'd trade my old beat up 34 for one, just for fun and to mess around with it.

    -Walt

  71. #71
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    Quote Originally Posted by Walt View Post
    Yeah, I don't know how much aftermarket tuning is possible here, but I'd assume it can be done with enough time/money/determination. And really, a fork this expensive should really be tunable out of the box for even extremely picky riders.

    But yeah, I'd trade my old beat up 34 for one, just for fun and to mess around with it.

    -Walt
    Of course, at the end of a Santa Cruz ride, I see this. Leaking damper. I have no idea who has been thrashing this fork before me so I can't say whether I caused it or not. In either case, we just took the relatively mellower trails back to the truck. I can unequivocally say that this fork is the best carving/turning fork, by far, that I've ever used. It also climbs well. I can't wait to try the 2nd or 3rd generation. For now, it's going back to the LBS that let me demo it.
    Attached Thumbnails Attached Thumbnails Constant trail suspension fork?-td46nxc3raqn5hr-x6edsw.jpg  


  72. #72
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    The fatal flaw I see in the linkage forks for bicycles is that the linkage arms are way too short. They need to be long to minimise rapid changes in geometry otherwise they are limited to small arcs of effectiveness.

    I suspect fashion has something to do with this, they are trying to cram the mechanics of an odd looking (to the consumer) fork into a silhouette not too radically different from what they are used to, so long linkage arms and an external shock would be an even more difficult sell.

    I have a small collection of bicycle linkage forks, and frankly, they're all disappointing. The common denominator is short links. The problem with longer links is that they are going to be much more flexy unless considerably beefed up which adds weight (which may not a problem with a carbon arm).

    Fortunately humans can ride unicycles, so minor variations in bike geometry as the suspension goes through its travel are something we can handle.

    A telescopic fork has the advantage that its changes in geometry feel progressive. A short link can have quite a dramatic change at the "wrong" part of its arc - that can be somewhat mitigated by using unequal length links in a parallelogram which can extend the usable travel, but with an even more dramatic sting at the end.

    However a suspension fork should not be looked at without considering the frame it is attached to, eg front suspension movement on a long wheelbase has less effect on head angles for a given amount of travel, with a consequent reduction in trail alteration.

    (NB I am discussing forks for dealing with trail irregularities, not leaps into the great beyond such as downhillers use)
    Last edited by Velobike; 12-30-2018 at 09:09 AM.
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  73. #73
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    Quote Originally Posted by LyNx View Post
    Call me skeptical, but all of a sudden after a not glowing review of this fork by 7 different riders is released, there is this glowing review by one guy, with no interaction with this thread until after the bad review, who also happens to own an Evil
    Don't know him personally, but been reading his mtbr posts for a loooong time. Flipnidaho is arguably one of the most objective non-fanboy members of mtbr, and has been for the past decade or so. He's got the resources to own many bikes spanning many brands.

    It's not like he created a new account to shill a $2700 fork. Reading his quick review makes me think he was being nice and objective instead of going full keyboard expert gear tester warrior.

  74. #74
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    Quote Originally Posted by Velobike View Post
    (snip) The common denominator is short links. The problem with longer links is that they are going to be much more flexy unless considerably beefed up which adds weight (which may not a problem with a carbon arm). (snip)
    This is why I'm still planning on evaluating a bike packing specific suspension fork (what, I want one). Make the linkage arms as long and subjectively ugly as ya want, then cover the whole thing up in panniers. What I've noted as a somewhat consistent theme with packers is that not a whole of the bike remains to be seen under all the bags.

    I did take a look at my old CAD sketches on this notion, and they smell a little bad. Planning some re-evaluation, influenced in some part by this thread.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  75. #75
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    Quote Originally Posted by Drew Diller View Post
    This is why I'm still planning on evaluating a bike packing specific suspension fork (what, I want one). Make the linkage arms as long and subjectively ugly as ya want, then cover the whole thing up in panniers. What I've noted as a somewhat consistent theme with packers is that not a whole of the bike remains to be seen under all the bags...
    From my motorbike days, I reckon this was a good linkage fork* from the viewpoint of torsional stiffness and its ability to soak up whatever was on the road. Note its brake linkage - with suitable mounting points it could be adapted to control dive.



    Done in carbon it could be relatively light, but the fugliness index to the unaccustomed eye wouldn't help sell it (personally, I like it because it works). The monocoque construction means you could hang all sorts of gear off the side of the fork.

    And you could hide the fugliness under your backpacking gear.


    *Bear in mind my comparison was with motorbike forks of the time, but its compliance was very good IMO.
    As little bike as possible, as silent as possible.
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  76. #76
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    Quote Originally Posted by Structure-Ryan View Post
    An alternative way to configure the bike is to use a steeper head angle to provide stability comparable to a traditional bike under rowdy conditions and vastly more agile handling when climbing. Or somewhere in between. The point is that it flips the stability situation: telescoping forked bikes are at their most stable when extended (ex. climbing) and least stable when descending or hitting things. The Trust fork or our Structure bikes are most agile when extended and most stable when compressed. We think you'll agree that's how it should be.
    This one of the things is that the Tantrum "missing link" rear suspension does, amplified 10x.
    A Tantrum with a linkage fork would smash any superbike in existence.

  77. #77
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    Just had an idea. Would it be possible to have a telescoping fork have a more forward axle path (thus increasing trail) by making the telescope steeper that the head angle? Basically, with the wheel axle in the traditional position, the legs's feet would be a bit farther back, and the crown would have a forward offset. The axle path would be linear, not as refined as a curve but still an improvement, at a normal price. And the increase in bushing stiction (due to steeper telescope) would'nt be a problem with a Lefty design

  78. #78
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    Wait a minute. If the axle moves forward (compared to a telescopic fork) offset increases, so trail decreases. Where's the increase in stability? From the increase in front center? I don't think it makes for a 30% reduction in trail...

    What we need is either a strong anti-brake-dive (Motion fork) or decreasing steering angle to counter the increase cused by dive (which can only be obtained by making the steerer a part of the sprung linkage, like in the Structure). Weagle's does nothing of that...

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