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If Roger Decoster was to give it the nod they'd be all over it i bet regardless of the results.
“ Roger DeCoster tested the fork and believed in it so much that he put it on his works Suzuki and raced the 1979 500cc World Championships on it.”
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Who’s the guy that said “winning is the best deodorant”? Cause that guy was absolutely right!
Suspensionsmith is a clever man - far from the usual snake oil salesman / customer ripping off 'gurus' that the Suspension industry is Full of. I've been a part of it since the early 70s, and have little time for the majority of it.
So, it's something different. Not what I'd do, but it's what He wants to do. His Road Bike front ends ( if I'm thinking of the right person / company) are very trick, very impressive.
He's got a thread over on Thumper Talk for those that want to see more, since he's decided to depart this thread / site.
He's got it to production level, and it's for sale. It looks good in it's ready to sell state.
I'm sure he'll have buyers, there's plenty of blokes / blokettes out there with money, that want something different. Good on him.
The big thing I have Serious reservations about is the use of MTB shocks. I've been involved in that side of things for decades now, and they are Not strong enough. Shaft eyes breaking ( shearing/ collapsing), body eyes the same, Bodies themselves collapsing / concertinaing, and the inner tubes of twin tube dampers doing the same, Bodies shearing at the eye / body interface, Seal Heads / Seal Head Caps collapsing. And, you've got the near universal use of 12.7mm / half inch wide and reducer pin / bushing usage at eye pivots. Trunion mounting has proved to be , in so many cases, a problem. And all of that's Not just on the myriad of poxy, BS designs used as USPs by manufacturers to tout as the latest, greatest things. That so often, introduce fearful mechanical loads into what are tiny, minimalistic shock absorbers.
The EXT Storia shocks aren't much, or any better than any of the others. It has little to do with shaft sizes, but mainly eye support and design, at either end of the shock. Even with a design with purely compressive final, at bottomed loads, I feel they are far from strong enough with the weight of a Motorcycle. The bloody things break on bicycles, and Not just from shithouse, gimmicky linkage designs.
I think I put forward here, or elsewhere, that I feel a bottoming stop needs to be designed into the linkage, to Not rely on the MTB shock as the final bottoming stop in his design. Perhaps he has done this?
There is sweet FA leverage ratio to his shock linkage, but it just comes down to how flimsy the shocks are, when finally everything is bottomed, with so much more force being put into the shocks when they are on a motorcycle.
My tirade purely is against the shock solution he's using - I admire his overall design ( not what I'd do, as I wrote earlier, I have my own ideas for "funny front ends" ), and all of his other work. As I said, he's a clever bloke, who does Great work. Far above damned near all of Suspension "experts" out there.
On the topic of MTB shocks...pretty well agree with everything you said...they have a terrible eyelet/bushing design with poor ability to tolerate misalignment and frame flex side loads on the shock...rubbish idea....much to much emphasis on light weight.
These EXT shocks I am using are a new design out for about a year now which are specifically designed around the heavier E bikes and E MX bikes becoming popular now...its called the E Storia.
These shocks have a much beefier eyelet design and use spherical bearings to tolerate any misalignment...they use a 14mm steel shaft and a beefier interface between shaft and eyelet and the bodys are stronger...so less emphasis on light weight more on strength/durability.
As you mentioned my installation uses a 1:1 motion ratio between wheel and shock and the shock typically uses a fairly light spring rate of 350/375lb...which is light even for a mountain bike....with a 57mm stroke so total spring force is moderate at full bump...then their is the fact that there is a 310mm travel fork "between" the wheel and shock....so peak shock loadings are again moderate....this front suspension has a total travel of 370mm so you have to be trying very hard to bottom it hard....normal tidy fast riding the front feels bottomless....
You have put a shit tonne of work into this I'd be very interested in testing one done time.
I don't have the issues on my Frames that I pointed out, as I use a single pivot, scalene triangle set up that ends in a perfect right angle , so dead straight compressive forces are delivered at the theoretical metal to metal bottoming of my design. And, as I no longer live by frame sales, I can pick and choose who I sell to, educate the owners, and maintain the shocks. That's a Key Shock longevity issue, what with the way most Bicycle people approach suspension maintenance. I don't like the nylon bushings, that are so prevalent now, I prefer the DU type as a reinforcement of the piddly little eyes that are on the vast majority of shocks. Beefier eyes with a spherical bearing, as the EXT Storia has, would be So Much more preferable.
I was going to suggest you look into some of the brands that make specific shocks for the FSAE cars. Some can be much beefier than MTB shocks, while still being quite small. Both the Tar ones and Off Road ones. I had a fair amount to do with FSAE, years ago, and pushed the 57mm travel shocks ( of the same 7.875" / 200.025mm eye to eye length) over the 2" travel ones, for a bit more versatility, and the possibility of a a reduction ration , so to speak, being used on the shocks. Bloody Hell, dealing with 'know it all' University Professors / Lecturers, and ( what I referred to them as - and, still do) ' baby engineers', can be a trial....... And their 'Payments' methods, that they tried to force on me, well, they could f*** right off! They had a hard time, paying for things up front. They seemed to think that damned near 365 Day Accounts was how should be. Ah, Academia, it's such a bloody Weird World - that I've become a part of, in the last decade and a half........
Good luck to you with your design, the 'on sale' product looks great. I do love "funny front ends", though, the Engineering Abomination that Telescopic Forks are, are Very hard to better. I'd love to have a ride on one, but, at the moment, and, it appears, for quite a while, I'm stuck on Wheelchairs, Walkers and Crutches. Sucks getting old, with injuries, old and new, catching up with you.
I thought you were reducing the travel of the Teles, with the addition that the shock and linkage brought. 370mm of travel - that harkens back to some of the travel numbers tried in the early days of the "Suspension Revolution". Interesting indeed.
On Yah, Suspensionsmith - don't ever let the bastards grind you down!
I did some clamp testing on my downhill bike and tried 58mm, 46mm and 43mm. ridiculous how much more stable it is the shorter you go. The long ones where super twitchy.
“ A longer trail measurement gives greater caster effect, heavier and slower steering, and a more stable feel in a straight line. That is exactly what less fork offset should achieve. Conversely, more fork offset reduces trail and should cause the bike to steer lighter and quicker—and the front end to feel more nervous in a straight line”
Sounds awesome. Guys like you are why we get nice things.
If you take a close look at the 450sxf bike I posted up you will notice the forks sit at a different angle to the steering head and steering axis...they are angled forward and steeper.
Most/all bikes run their forks in parallel with the steering axis with the result that their wheel offset doesnt change with just suspension movement....hence trail only changes where the bike pitches forwards or backwards as the steering angle changes in relation to the ground....forks work or steer so well because they change trail correctly for a given circumstance...reducing trail during corner entry for agile steering and increasing trail when accelerating off corners etc for increased stability....but they can be better....they just need to change trail in these circumstances to a greater extent....
A really straight forward way to do this would be to mount the forks at a different angle to the steering axis in a similar way I show on the 450sxf bike pictured.....this means as the fork compresses the wheel offset increases...hence trail is reducing...this means that when you are entering a turn you get trail reduction both from offset change and forward pitch change of steering angle....the reverse is the case when the forks extend when accelerating away from a turn..... wheel offset reduces and the bike pitching back for a both greater increase of trail.
What this means is you get a greater variation in trail overall....you can set the bike up to have lots of trail under hard acceleration for great steering stability.....and then when you brake etc and enter a turn you get a greater reduction in trail for great steering agility into and through the turn....you get a much better balanced steering between stability when it needs to be stable and agility when it needs to be agile.....
Pit Row
https://youtu.be/7S-C2pic7UQ
https://youtube.com/shorts/oUCwCyWk-P4
I have the 450, got rid of the air forks and installed Dal Saggio forks, 105 sag, stock rear with 1 click softer on high speed and low speed, 6mm through the clamps to shorten the turning circle.
Handles great, no head shake at all.
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