Are they really a game changer? I guess until we see Sam Hill etc winning WEC events on them we might get the answer, I have just descended Dollywagon from Helvellyn on a rather naff 2016 Fox 36 with crap low speed Compression damping (Blocked circuit? not sure) and it got me thinking.

They still require damping, which presumably can still need servicing/fixing. Anyway, all about axle path. If anyone does ever get one properly sorted, we’ll know about it.

In theory a shock-sh-borber should be cheaper to service than a overly complex fox damping circuit though or am I wrong

Whether the damper is “complex” or not has nothing to do with the fork being telescopic or not. Cheaper postage you could argue I suppose, assuming dampers can be removed from the linkage fork.

Trust Performance looks interesting and might be able to change some minds. Telescopic forks are highly flawed, they work in the wrong direction, are inherently flexible, when they do flex it affects their performance etc, but over the years this imperfect design has been developed and refined (a bit like the chain driven drivetrain), and made cheaper over a couple of decades or so now, which has hidden the fundamental flaws pretty well and as users we’ve all become accustomed to them so any new system will definitely feel different so will ultimately take some time for people to adjust to, get the most out of and come to like and prefer. Unfortunately for any new kids on the block there is an unwillingness for people in any large number to take the plunge and be the early adopters of a new system. So any development and refinement of a new type of fork would take alot longer and people don’t have the patents and investors don’t have the funds to risk. The new Trust Performance fork is £2,500 which is hell of a lot for a fork full stop, let alone for a novel design and unproven product. You’ve really got to want one to take the plunge and the risk. However I’m betting that the Trust Performance fork right now in its first generation version will be a million times better than the first few generations of telescopic forks that hit the market 20 or so years ago. If there was a version that was at the same level of development and refinement as current modern day telescopic forks, then you’ve got a fair comparison.

I guess until we see Sam Hill etc winning WEC events on them we might get the answer

That’s not the best measure of the relative state of equipment. Not sure what DH racing is like today as I’ve not followed it for a couple of years, but not so long ago metal framed DH bikes were still in the game, competitive and beating carbon framed bikes, so even in the hands of the pro’s it takes a while for new tech to come on and get to a state of refinement where the benefits can shine through….or (more likely) the marketeers force the new tech through because at the end of the day the Pro’s don’t get a say about what they ride…they ride the kit they’re paid to ride.

I think one of the hurdles is aesthetics. We are used to the design of telescopic forks and uses to thinking they look good.

When I rode a linkage fork 23 years ago – it was because the Amp F3 forks looked superficially like the Project 2 rigid forks they were replacing. So the aesthetics worked in their favour. Now, I think that just works against most of them.

I don’t think we can forget that several linkage forks were crap. Look Fornales were lethal out of the box. My own Amp forks were subject to huge pivot bushing wear. Girvin forks were pretty much rigid in my experience. That’s a lot of negativity to overcome.

Wasn’t it the Trust Performance forks that have been slated recently…. for being a bit, well, crap?

Apologies if I’m thinking of the wrong forks as there is another linkage fork coming to market/in market as well.

Yeah Trust have been slated in a few reviews, I reckon the problem is partly due to the axle path – it’s only rearward for the first bit – because of the head angles on modern bikes, telescopic forks actually have a fair amount of rearward travel.

1. They’re ugly.
2. They’re expensive.
3. They’re ugly.
4. Jury is out on performance.
5. They’re ugly.
6. Jury is out on durability.
7. They’re ugly.

Full disclosure…. I used to lust after that Whyte.

The main problem with them is by using a standard frame it is impossible to get all the benefits of lever forks. Really a frame built for an alternative front end is needed like the whyte ( but that has serious flaws of its own)
I have been following and using alternative front ends on motorcycles for decades. I had a BMW with the telelever front end. This design has inbuilt anti dive without locking the fork so you could run much softer springing and not have the fork collapse under braking. This then allows you to run much shorter trail without losing stability. Also the suspension components didn’t turn with the steering thus reducing the steering inertia and unsprung weight. A huge improvement in roadholding. Steering was both fst and light without loss of stability which I would think would be good on an mtb. However the feel was different and took a while to get used to.

I’ve had a number of linkage forks, and none have fulfilled the promise. Yet the basic principles were well established many years ago on motorbikes.

A decent girder fork is capable of handling high speed and substantial impacts and handles well.

One of the fundamentals is that there is a great big long lever so the pivot points need to be really robust, and most bike forks didn’t pass that test.

The axle path with a linkage fork using equal length links is the arc of a circle, so obviously it needs to be constrained to the part where the axle is travelling in the more vertical part of the arc. When short links are used, as on most bicycle linkage forks, that does not provide as much travel as we are accustomed to with a telescopic fork

However bear in mind a lot of the telescopic fork’s travel can be used up in brake dive whereas that can be designed out of a linkage fork so it is not a straight comparison.

Trying to overcome that by using unequal length links leads to some strange transitions in axle path at the extremes of movement which is not a good thing for control in extremis.

I think a linkage fork needs to be kept simple – use long links to get a decent amount of travel and constrain the movement rather than try with multiple pivots and links to replicate a telescopic fork.

The problem with that fork is as tjagain says, it would not be a bolt on to a frame designed for a telescopic fork.

I really like the bmw telelever system. To me it answers most of the criticisms of linkage front ends and minimises drawbacks. Braking over bumps is uncanny as the bike dives and inch then no more – and the front wheel still tracks every bump on the ground without skipping or allowing any impact thru to the rider.

Girder and leading / trailing link forks are still compromised as the suspension components turn with the steering and braking forces still go thru the steering head. You get the main advantages by separating these functions out so the suspension components only go up and down. The sliders and stanchions have much more overlap than a conventional tele fork thus are more rigid for the same weight. The steering head does not need to be as strong as the braking forces go into the frame low down via the wishbone.

first generation version will be a million times better than the first few generations of telescopic forks that hit the market 20 or so years ago

Whyte, AMP, Girvin, USE…quite a few generations/attempts already?

first generation version will be a million times better than the first few generations of telescopic forks that hit the market 20 or so years ago

They’re not competing with those old forks, they’re competing with current forks. For $2300, they are going to need to be better than the current top end RockShox and Fox forks, not an old Judy or whatever with 28 mm stanchions and 60 mm travel.

If you do yer basic trigonometry, it is quite easy to achieve a straight enough axle path over enough travel with unequal length linkages that aren’t too long. Fitting in a spring and damper is needed on top of that. Or beside it, or inside it etc.

That is with a design of the “the whole thing steers” type, rather than where the steering bearings, or one of them at least, moves up and down. The latter type appear more problematical on a pedal cycle because of space and the amount of travel folk now want.

Reading the reviews of that Trust Performance fork, it appeared to me that the problem was the springing/damping rather than to do with the axle path.

Is it common to fit aftermarket suspension on motorbikes? Not that I’d want to trade the modularity of a bicycle, but it does have some limitations compared to a frame and fork designed to work together.

Yes quite common to swap bits around on motorbikes. I put a better adjustable front shock in my BMW ( much easier and cheaper upgrade than replacing the whole fork on a conventional bike), many folk upgrade / swap forks and shocks putting forks from later models or aftermarket ones on.

Kelron – it’s not uncommon in the customising world to change the “front end” on a motorcycle, either as a straight swap or by getting custom yokes made up.
Back in the day a mate made his own design of linkage forks and fitted them to an FJ1200, but that was mighty impressive & definitely not the norm.

In the motorcycle world there has been a lot of work done on alternative front ends and some production bikes with them. As well as BMW with two different designs there are various scooters with alternative front ends including one ( a Gilera?) that had proper hub centre steering. The Britten race bike had a girder front end. Honda Cubs have a short leading link. the elf racer had various incarnations of hub centre steering., Back in the classic Era Greaves had a long leading link type suspension

Royce Creasy and Jack Difazio are two blokes that did a lot of work in the area. I guess if you google them you will find a fair amount of detail

Thanks for the comprehensive responses, and a interesting bit of tech

I really like the bmw telelever system. To me it answers most of the criticisms of linkage front ends and minimises drawbacks. Braking over bumps is uncanny as the bike dives and inch then no more – and the front wheel still tracks every bump on the ground without skipping or allowing any impact thru to the rider.

Axle path is still crap, which is why the BMW design doesn’t work in motocross. That and the design only allows you to package about 6-8 inches of travel in the front where as motocross bikes are running around 14.

Reading the reviews of that Trust Performance fork, it appeared to me that the problem was the springing/damping rather than to do with the axle path.

It goes vertical in the latter half, when you’re banging through rock gardens at full speed that is going to be felt as harshness through the bars. That is one of the major complaints I have seen of the fork. The people who get this are the people who jump from a normal bike to a high pivot bike, the lack of harshness on square edge hits and the way they carry speed is noticeable. I’d say it’s more noticeable than moving from a 26 inch bike to a 29er.

Steve at Vorsprung considers the Ribi leading link fork to be the best historical attempt at an offroad linkage fork, not the BMW telelever – I’d rather listen to Steve, him being an engineer.

However bear in mind a lot of the telescopic fork’s travel can be used up in brake dive whereas that can be designed out of a linkage fork so it is not a straight comparison.

Except that spend 90 percent of your time off the brakes, why would you sacrifice grip on 90-95 percent of the track for a little extra grip for 5 percent of it?

Brake less.

raybanwomble

… why would you sacrifice grip on 90-95 percent of the track for a little extra grip for 5 percent of it?

Because that’s when I really really want grip…

Rayban – telelever works – the axle path is spot on. You don’t lose any grip – you have MORE in all situations as the unsprung weight is lower, the spring rate is a lot lower because it doesn’t need to deal with braking forces and the suspension stillworks when braking rather than either locking up or diving to the point you get ridiculously high spring rates leading to skipping over bumps. Yo also get a lot better small bump sensitivity as spring rate is lower and stiction is less. You get better steering control as its a lot stiffer

As when we discussed this before all you do is show that you have no experience and little understanding of these

Ever ridden a bike with an alternative front end? I have ridden quite a few.

Rayban – telelever works – the axle path is spot on. You don’t lose any grip – you have MORE in all situations as the unsprung weight is lower, the spring rate is a lot lower because it doesn’t need to deal with braking forces and the suspension stillworks when braking rather than either locking up or diving to the point you get ridiculously high spring rates leading to skipping over bumps. Yo also get a lot better small bump sensitivity as spring rate is lower and stiction is less. You get better steering control as its a lot stiffer

So you are saying Steve, who is an actual engineer is wrong? The BMW telelever has an L shaped axle path, there is a reason why BMW leave it off their real off road motorcycles. Brake dive is immaterial if it allows you to run extra travel with a sensible axle path.

Because that’s when I really really want grip…

Only if you ever ride at the edge of your grip under braking.

stiffer

Why is that necessarily a good thing? 40s are already too stiff. Motocross riders drill their crowns. MotoGP is always looking for more lateral flex. No one is going for linkage forks for more stiffness. Only you TJ.

raybanwomble

…Only if you ever ride at the edge of your grip under braking.

Yup, that’s exactly when I want grip…

Other people ride at the edge of their grip all the time. Thus you are sacrificing time against a clock when not under braking for time under braking. Again, no one in Motocross is going “you know where I need to make up time? Braking” and demanding linkage forks because of that.

As above rayban – you don’t understand and you have no experience and every post you make on this makes it ever more clear.

So TJ, why do BMW not use it on their proper off road motorcyclea – why does Steve think the Robin fork is the closest we ever got to a real off-road fork? Were HRC Honda idiots for using a leading link fork? Or do perhaps the last name in motorcycle racing know what the **** they are talking about?

https://www.vitalmx.com/photos/member/Bikes-w-the-number-1-plate,35911/worksstory,43079/ocscottie,405

https://motocrossactionmag.com/leading-link-or-missing-link-the-awesome-fork-that-time-forgot/

Leading link forks are still used in sidecar motocross to this day. Lighter and stiffer especially laterally with not as much travel needed due to the antidive geometry. You don’t need 14″ of travel if yo have inherent antidive

Different solutions have different compromises and are best suited to different things. The telelever is the best for a large touring motorcycle with medium travel.

Leading link forks are still used in sidecar motocross to this day. Lighter and stiffer especially laterally with not as much travel needed due to the antidive geometry. You don’t need 14″ of travel if yo have inherent antidive

You do if you are getting a lot of air time and smashing through whoop sections at warp speed. Moto sidecar events are smoother with smaller jumps and I’ve never seen one with a whoop section. It’s funny that the the linkage fork development on sidecars has never translated well over to moto isn’t it? Motocross riders also like to shorten the wheelbase in certain corners by actually using the fork dive.

Leading link forks had horrible issues with rise under braking as well and had to have floating brakes installed, good luck packaging that on an mtb efficiently.

You are dead right about the telelever being a good fork for touring motorcycles as they offer a good margin of safety and stability if you aren’t going at race speeds.

Linkage forks have the potential to be great, it’s just they aren’t anywhere near developed enough yet to work on motos let alone bicycles – I don’t think they will be for another 15-20 years. They have so many things to get right, packaging, reliability, spring rate properties, axle path – it’s going to take someone throwing a lot of money at R&D to do it in the bicycle world – Ohlins, Sram or Fox. throwing a significant amount of investment at it, only for everyone to then copy and undercut them.

Part of the issue is that it requires suspension designers trying to become chassis manufacturers and chassis manufacturers/racing teams trying to do suspension. At the moment Ohlins provides most of the suspension expertise in Moto GP – they have decades and decades worth of data and experience. Do you think HRC Honda would go down the route of linkage forks if they could better Ohlins at their own game? They would – the problem is that they don’t think they can better Ohlins.

I refer the right honourable gentleman to the answer I gave earlier. You really do not understand the issues at all do you. Too busy trying to score debating points.

Understand what issues TJ – that you can’t handle a little bit of brake dive on a fork? Or is Steve wrong about why it’s so hard to get a linkage fork right? Is there not a reason why Moto GP hasn’t gone to linkage forks? Why have motocross teams not gone to linkage forks? Why does “it doesn’t dive under braking” make something a better racing or off road fork, when track timings and comfort are predominantly dictated by the way the fork behaves when off the brakes?

If you still think that axle path makes jack shit difference – go and weld up a bike with a 180 degree head angle and tell me how it feels going over bumps.

the fact that tj bangs on about motorcycles in these threads kinda just reinforces the point that they aren’t that successful, otherwise, you’d be talking about mountain bikes, right?

The new Trust Performance fork is £2,500 which is hell of a lot for a fork full stop

especially for another linkage fork that (just like every single other linkage fork that there has ever been) over promises, and under delivers on performance and is a bit shit to boot. Imagine how disappointed the folk that have bought one must be feeling tight now, poor things. A linkage fork would have to be a measurable step up in all areas of performance on a bike for me to ever consider one including servicing, and let’s be honest; all those pivots aren’t going to make the job more simple are they? And the least of my worries is brake dive BTW, which most enthusiasts of these forks seem to think is a game changer (hint: it’s not even something I think about)

I’m all for innovation, but linkage forks are a busted flush and not in the least bit new or an improvement of tele forks on MTBs , they never have, and never will be, 20 plus years of trying must have proved that by now, surely? whats that well know phrase…The definition of madness is doing the same thing over and over and expecting a different result…

*sighs*

I didn’t say axle path makes no difference. One of the advantage to linkage forks is tailoring the axle path to do different things at different parts of the travel

another that again yo don’t understand is that linkage forks give different effctive spring rate and damping rates at different points in the travel or can do – something almost impossible with teles

Every post you make on this rayban simply emphasises that you do not understand the issues at all, you are not interested in learning, you have no experience and all you want to do is score debating points off me.

Why you have this attitude I don’t know but it stinks up threads and kills them. Well done for doing it to another one

No point in debating with you – the dunning kruger is too strong.

Nick – I think the main reason for the lack of successful alternative front ends in MTBs is that to get the full advantages you need a redesigned frame – and that then locks you in to that frame and fork and is thus an expensive buy in. Like the whyte posted above. Unfortunately that is fatally flawed by the short top linkage giving it an axle path that does not work well. Any alternative front end that can be fitted to a conventional frame starts off with a set of disadvantages and not be able to get all the advantages

Would you like a fork that has a lower spring rate so improved small bump sensitivity but that still does not collapse under braking or big hits? to be able to tailor in rising rate at the rate you want that also includes damping? Less stiction so again better small bump compliance? Less flex for the same weight or less weight for the same flex? simpler damping circuits that give more sensitivity and adjustment? To be able to work with a low spring rate even under hard braking? No more chatter over braking bumps just a wheel that tracks the ground and allows you to brake hard over rough ground?

All these and many other advantages are possible It doesn’t even need to have a lot more pivots – the telever type design has two extra simple pivots that are not highly stressed

having ridden a telelever motorcycle a lot its uncanny how the suspension still works under braking and how much the small bump compliance is improved. This would be very noticable on an MTB would be my bet but you cannot get these advantages without a redesigned frame

And the least of my worries is brake dive BTW, which most enthusiasts of these forks seem to think is a game changer (hint: it’s not even something I think about)

Learn to brake harder, then you’ll think about it.

nickc

…And the least of my worries is brake dive BTW, which most enthusiasts of these forks seem to think is a game changer…

Once you’ve ridden a bike that compensates for brake dive over a rough surface while using the brakes, you’ll understand why there is the enthusiasm.

I’ve owned/ridden many of the motor bikes tjagain references, and I know a good linkage fork works well, but as I’ve said before, I haven’t ridden a bicycle one I’d consider good.

And why don’t racers use linkage forks? I don’t care, I’m not a racer, and I don’t have a racer’s suspension budget.

I wouldn’t want one for fast techie stuff. I think there’s something in the action of a tele fork that really works with a slack angle and techie trails. I would try one though on an adventure bike, to take the edge of washboard or rough tracks. Currently that would be a Lauf fork, but maybe some other option will come along. If I won £72m on the lottery I’d try one of those Trust ones but not on my tech bike.