[Honus]

I've seen the Wimmer before- it's basically a modified version of the SaxTrak/Telelever fork with the big difference being that it has a dual chamber system. The bottom fork legs are independent from the top if I remember correctly- that's how he gets a large amount of travel without the severe geometry change. I'll have to read through his patent.

I think a shorter travel Telelever system makes a lot of sense for a 29er- I drew one up a couple of years ago that was pretty silly. There was a triangulated A arm that activated the shock (connected to the sliders just above the tire) and the fork was designed to run on recirculating ball bearings to reduce friction. The trick was keeping the front of bike narrow enough so you wouldn't bang your knees on the A arm pivot. I'll have to see if I can find a pic somewhere.

 

[NWS]

http://www.lazareth.fr/

Their web site is (f@#$ing) Flash-based so there's no way to link to anything specific. But, if you click the British flag (language choice) near the bottom, and then "models for sale," and "bikes," and click the right-arrow enough times, you'll see a couple crotch-rockets with linkage front suspension. Click "download PDF" for the VMax model, there are a couple of shots of the linkage from different angles.

Yes, the navigation is Flash and the images are in a PDF. Really.
Hopefully their bikes are more use-friendly than their web site.

 

[Wilhelm]

There are lots of funny concept bikes to find in the web. One of the most weird I found, besides e.g. the "DODGE Tomahawk", is Julien RONDINO´s "A.3.W Motiv", an in-line three-wheeler with hub-center steering.

Unfortunately, most of interesting suspension conceptions concern to short-travel motorbikes and cannot be transferred simply to long-travel lightweight MTBs.

 

[Steve M]

I may well be drunk off my tits but there is no ****ing way that would make sense even if I was sober.

 

[Wilhelm]

Indeed, a very unusual vehicle . The 3-wheel in-line configuration is said to reduce the risk of slipping down in curves, to improve brake performance, and finally to make biking more secure, among others.

However, the bike reminds me somehow to two equally bizarre Formula One racing cars:

TYRELL P34 (1976-77)

MARCH 2-4-0 (1977)

 

[Honus]

Ahh...the six wheelers. Williams also built one as did Ferrari (and Auto Union much earlier.) The March and Ferrari never raced and six wheelers were banned before the Williams could gain any traction (ha ha.) The Shadow CanAm car also had super small front wheels (and it used die springs for suspension) but was hampered by the ability to get decent tires.

The inline three wheeled motorcycle is about as dumb as it gets- as if the dynamics of two wheeled vehicles aren't complex enough already...

 

[Honus]

For a long travel setup that will mount onto an existing frame I really think something like the Ribi quadrilateral is the way to go. Here's some pics of the earlier versions (before DeCoster convinced Honda to buy it)

 

[Honus]

Here's an exploded view of the MotoCzysz fork- it's quite a bit different from a Headshock (although it does use needle roller instead of bushings.) The sliders are empty except for the bearings and the shock is a complete bolt in assembly that can be removed/swapped very quickly. Honda test riders were shaving something like 2 seconds per lap with this fork and they say the feel is unbelievable- a pretty impressive feat for a moto road racing fork. It would be difficult to implement in a long travel bike fork with a standard steerer without having the shock actuate through a linkage, which wouldn't be anywhere near as clean.

 

[Steve M]

For a long travel setup that will mount onto an existing frame I really think something like the Ribi quadrilateral is the way to go. Here's some pics of the earlier versions (before DeCoster convinced Honda to buy it)

I am inclined to agree. The Ribi layout is the only way to get a linear axle path as well as controlled anti-dive characteristics. It does have packaging issues though, because those links swinging backwards at the down tube need to be restricted in order to not smash into the downtube (or radiator/frame on a MX bike), and it's hard to get a shock in there without either a 6 bar linkage (a la HRC bike), mounting between axle link and forward link, or having a falling rate design.

 

[Pslide]

The Ribi is pretty interesting. Sounds like Honda owns the rights now. I wonder if they considered it for the RN-01?

Honus, why was the MotoCzysz fork so much quicker? Was that just down to lack of stiction from seals and bushings?

I found it surprising that the Lefty (also needles) gets very good reviews to this day...

Loving the amount of tech in this thread!

 

[Honus]

I am inclined to agree. The Ribi layout is the only way to get a linear axle path as well as controlled anti-dive characteristics. It does have packaging issues though, because those links swinging backwards at the down tube need to be restricted in order to not smash into the downtube (or radiator/frame on a MX bike), and it's hard to get a shock in there without either a 6 bar linkage (a la HRC bike), mounting between axle link and forward link, or having a falling rate design.

Yep- the second I did a rough sketch of one superimposing it over an existing design I thought boy that thing is going to smash the downtube. I figured the HRC version is really the way to go given the existing shocks out there but even then the packaging is going to be pretty tough, especially if you have a bike with a short head tube. Keeping the weight down would be difficult and/or expensive.

 

[Honus]

The Ribi is pretty interesting. Sounds like Honda owns the rights now. I wonder if they considered it for the RN-01?

Honus, why was the MotoCzysz fork so much quicker? Was that just down to lack of stiction from seals and bushings?

I found it surprising that the Lefty (also needles) gets very good reviews to this day...

Loving the amount of tech in this thread!

Honda shelved the Ribi pretty quickly (they only very briefly used it during the works MX era) but they did make a proto for a road racing version that I think Freddy Spencer tried out and really liked. Roger DeCoster loved it- I actually met him once back when I worked at Onza but I never had a chance to ask him about the Ribi. Honda has a history of building some super trick far out stuff as engineering exercises and once they've learned what they wanted (and got their patents) they shelve it.

To the best of my knowledge, the last Honda Ribi patent was issued in 1984. I think there were four patents total covering the Ribi design.

As for the MotoCzysz fork I think it's a combination of several factors involving reduced friction, improved fore/aft stiffness (especially under high braking loads) and improved lateral feel due to the lateral flex they engineered into the lowers. Every person that has ridden it has given rave reviews saying it's the best fork out there by far. I know Czysz has changed the company from a manufacturer to more of an intellectual property outfit so it'll be interesting to see if any manufacturer licenses the design.

I know Honda played around a lot with frame designs to introduce a certain amount of lateral flex into their GP bikes to try and improve chassis feel when the bike was at the limit, especially when cranked over. I think it was Eddie Lawson who said if you weren't comfortable sliding the front wheel through the turns then you simply weren't going to be in the top ten...

I have a friend that used to work at MotoCzysz- next time I chat with him I'll see if I can get any additional info.

Yep- people love their Leftys. I've never ridden one but I'd to get my hands on one to check out. I'm interested to see if there is any play at all in the bearings, especially on an older one.

 

[Pslide]

Regarding the Lefty needle bearing design (and the MotoCzysz) is there a limitation on the amount of travel that system will support? I think the longest Lefty they make is 140 mm.

The current Leftys are 3 lbs...which means you could use two and still have a 6 lbs double crown fork...wow.

 

[Honus]

I don't really think there's a travel limitation with the needle bearing sliders but I honestly haven't explored it in any great detail. The beauty of the MotoCzysz fork is its simplicity and similarity to a traditional telescopic fork while being able to remove the guts from the fork legs.

The biggest problem with all these ideas is packaging, followed by weight.

 

[Sandwich]

i thought part of the problem with the lefty design is that the bearings actually move as the suspension moves. therefore, you have a finite range that those bearings can move, and there's a face on both the uppers and lowers for them to slide. you'd have to have either tiny bearings, or huge faces for it to work.

 

[Honus]

i thought part of the problem with the lefty design is that the bearings actually move as the suspension moves. therefore, you have a finite range that those bearings can move, and there's a face on both the uppers and lowers for them to slide. you'd have to have either tiny bearings, or huge faces for it to work.

Yep- here's basically how they work-

The problem is when the fork is at full compression the rollers are up at the top of the leg so there's no support where the stanchion and slider overlap. It's not a problem for a short travel fork but for it to work with a 8" fork the fork legs would have to be huge to resist the bending force and you would need longer bearings and races, which I'm not sure would fit without increasing fork length. I'd honestly have to draw it up to see if it was doable.

The other option would be linear ball bearings since they are fixed in position like a bushing but the load capacity is a lot less than a bushing. They could work for a Telelever setup since you have the control arm that reduces the bending load where they would be held but I don't know if it would work for a traditional fork without making everything super huge.

There have been other linear bearing forks but they are all short travel systems that aren't really applicable. WP (White Power- that's a curious name for a suspension company) made one that had linear bearings and was single sided.

Troll built a hub center steering race bike with a linear bearing setup-

 

[Wilhelm]

Honus, do you have any informations about this obscure linkage-style fork design?

 

[Honus]

That's one I haven't seen before. It does remind me of a Collier. I do remember reading a patent a long time ago that showed that jack shaft chain drive system- I think it was called Traklever or something like that...

 

[Wilhelm]

That's one I haven't seen before. It does remind me of a Collier. I do remember reading a patent a long time ago that showed that jack shaft chain drive system- I think it was called Traklever or something like that ...

Indeed, astounding similarities. But finally nothing seems to come close to the Valentino RIBI fork design and the later HONDA improvements when it comes to offroad use. I hope that some capable maniacs would try to redesign and scale the RIBI fork down for MTB DH use that even makes it into production in the not so far future, light weight, stylish, and using composite materials ...

BTW, you seem to have an impressive collection of suspension related pics and data.

 

[Wilhelm]

Aww- you should have gone all out and built a Ribi fork.

I wish the skilled monkey guys would hear this call and act finally ...

The HONDA RIBI-type street test version with hydraulic disc brake but a lower step of evolution than the above MX version (twin shock, no extruded alloy profiles).

 

[Honus]

Indeed, astounding similarities. But finally nothing seems to come close to the Valentino RIBI fork design and the later HONDA improvements when it comes to offroad use. I hope that some capable maniacs would try to redesign and scale the RIBI fork down for MTB DH use that even makes it into production in the not so far future, light weight, stylish, and using composite materials ...

BTW, you seem to have an impressive collection of suspension related pics and data.

I used to have a huge motorsport/engineering library and I've been collecting all kinds of suspension design info since 1990. Sadly I sold most all of my books when my son was hospitalized several years ago but I still have tons of pics and info on my computer (and in my brain- hopefully.)

If I was to build a Ribi fork I'd definitely make it from steel first to work it out and then try to make a light version. It would be an undertaking to make that fork light and it certainly wouldn't be cheap! I do have some ideas as to how it could be done but that kind of project really needs a qualified engineer.

 

[NWS]

White Power- that's a curious name for a suspension company

I remember that brand from back in the day... I wonder if they just changed their name to White Brothers after the neo-Nazis gave "white power" a whole new meaning?

 

[Steve M]

I remember that brand from back in the day... I wonder if they just changed their name to White Brothers after the neo-Nazis gave "white power" a whole new meaning?

Nah, White Power are now known simply as WP Suspension.

 

[fluider]

White Brothers ...

9 inches of bushing overlap? Holy Mother Nature !

 

[Wilhelm]

I remember that brand from back in the day... I wonder if they just changed their name to White Brothers after the neo-Nazis gave "white power" a whole new meaning?

Nah, White Power are now known simply as WP Suspension.

"WHITE Power Suspension B.V." was founded by Wim PETERS in the Netherlands in 1977 and has nothing in common neither with "WHITE Brothers Cycling" (founded in 1996), now owned by MRP, nor with the "WHITE House" in Washington (DC) . The “WHITE” in the name of the company was derived from the white coated coil springs of their shocks as a special feature. They were renamed in “WP Suspension Austria GmbH”, and are part of the Austrian “CROSS Industries AG” meanwhile, like KTM Power Sports, too. "WP" is OEM for BMW Motorcycles, HUSABERG Motorcycles and KTM Motorcycles (the two latter both owned by KTM Power Sports) now.

Did "WHITE Brothers Cycling" have anything to do in history with the former MX supplier "WHITE Brothers", the exhaust line of which was acquired by VANCE & HINES, because they made suspension parts, too?

 

[big-ted]

There was a photo in MBUK YEARS ago, I'm guessing '93-'94, of a Diamond Back-badged concept bike. It was orange and silver and had a linkage fork. Essentially, it had a massively oversized front hub, to which two parallel links were attached that compressed a conventional monotube shock against a member that ran parallel to the downtube. The way I picture it now I'm pretty sure the fork would hit the cranks when you tried to turn, but it would be cool if anyone out there has a pic...

 

[Honus]

Did "WHITE Brothers Cycling" have anything to do in history with the former MX supplier "WHITE Brothers", the exhaust line of which was acquired by VANCE & HINES, because they made suspension parts, too?

Yep- they were one in the same. I used to know Dan White pretty well- super nice guy. Got to tour their facility in SoCal. They were also the guys behind the Rotec bike- I remember sitting in Dan's office and he was telling me about the design and how it would pivot around the BB shell, etc. I told him it would pedal like crap....

 

[Wilhelm]

Yep- they were one in the same. I used to know Dan White pretty well- super nice guy. Got to tour their facility in SoCal. They were also the guys behind the Rotec bike- I remember sitting in Dan's office and he was telling me about the design and how it would pivot around the BB shell, etc. I told him it would pedal like crap....

I see. That means John SULLIVAN did come into the ROTEC game at a later time?

BTW, WHEELER will come out this year with three new frames, each of them as a supported single pivot design.

And what would you guess where pivot is located?

Surprisingly around the BB.

It´s really weird, and I am curious how they would pedal.

 

[Vrock]

I see. That means John SULLIVAN did come into the ROTEC game at a later time?

BTW, WHEELER will come out this year with three new frames, each of them as a supported single pivot design.

And what would you guess where pivot is located?

Surprisingly around the BB.

It´s really weird, and I am curious how they would pedal.

They will pedal like crap.

 

[Honus]

I see. That means John SULLIVAN did come into the ROTEC game at a later time?

I think he bought Rotec in late 2001? The Lawwill Rotec is a whole different beast. This is the bike I was talking about-

 

[Sandwich]

They will pedal like crap.

yup!...

 

[Honus]

Found a couple more pics of the Ribi fork I had saved-

The RC250MT has kind of a hybrid of the earlier steel fork and the later version monoshock Aluminum fork

This is probably one of the best pics of the monoshock version

 

[worship_mud]

I think he bought Rotec in late 2001? The Lawwill Rotec is a whole different beast. This is the bike I was talking about-

LOL! a friend of had one of these and it was so f*cking long, it got thrown off the gondola as the rear wheel touched the ground and was leveraged off the hook when the gondola left the lower station...
later it broke literally in half while just riding along. those were the times...

 

[Honus]

Found the quick sketch I did (it's far from exact) to show the Telelever/SaxTrak fork idea I figured out for a short travel (120mm) 29er. I really don't think it would work for longer travel than that.

The idea is to use a space frame construction with a wide control arm at the front to support the fork. The main frame section is comprised of two triangulated structures joined together. The fork would run on linear recirculating ball bearings and have a 20mm thru axle. There is no headset- the bars are connected directly to the top of the fork. This is done to simplify construction, drop the fork/bar height and save weight. Of course this means the bars would rotate slightly as the fork moves, which is certainly disconcerting but it would be interesting to try. The fork will still have higher unsprung weight than a traditional telescopic fork- there's no getting around that.

The control arm pivot would be made from a wide BB shell and use an external bearing BB w/a large thru axle. The swingarm pivot is of similar construction. Yes it's a URT but I've already built this design before and it works well for a short travel bike, plus I can build it with really short chainstays w/good tire clearance, high pivot, etc. Unlike the old URTs this bike will still work when you stand. The radius arm that pulls the rear suspension linkage is triangulated- a single point at the lower link connects to the outer supports for the front control arm. The trick is getting the weight of the frame/fork assembly down to around 10.5 lbs max. Those are going to have to be some light tubes...

Like I said before it's a crazy idea...

There's more info on the SaxTrak fork here-
http://www.btinternet.com/~nigel.hill4/saxtrakforks.htm

 

[Steve M]

hahah, you're a nutcase and a wealth of information... build it!

 

[Honus]

hahah, you're a nutcase and a wealth of information... build it!

Which means I probably know just enough to be really dangerous... I figure why make things that already exist? I don't see the point in making copies of existing designs that are already pretty refined. It would certainly be an interesting project...I'll codename it Project Deathtrap. Now accepting donations!

 

[BmxConvert]

I haven't seen this guy posted up in here yet. It's actually kind of a sleek design.

 

[VMARTINEZ]

My Friends Dad has one of those. Its a super cool.
VM

 

[dw]

Just saw this, really cool EVRAC, nice work! I'd love to ride it sometime!

 

[dw]

However, the bike reminds me somehow to two equally bizarre Formula One racing cars:

I've had a soft spot in my heart for that Tyrell since I was a little kid. Is that weird? Probably.. But nonetheless.