Alternative motorcycle front suspension systems.
Alternative motorcycle front suspension systems.
(OP)
I am researching alternative front suspension design on motorcycles. If anyone has any good links to sites, or can recommend any literature or contacts, please get in touch.
I'm particularly interested in contacting designers.
Thanks
I'm particularly interested in contacting designers.
Thanks





RE: Alternative motorcycle front suspension systems.
Happy Searching.
MB
RE: Alternative motorcycle front suspension systems.
Start asking around BMW forums, or go to there web page. They currently have a telelever front end in production and are coming out with a doulever. Norman Hossack(probably misspelled) is the inventor of the Hossack or doulever front end and has some interesting things to say on his website, sorry no link.
If you are looking for center steer hubs, Bimota and Yamaha have produced working designs, I beleive the firm ELF did a lot of engineering on these many years ago.
RE: Alternative motorcycle front suspension systems.
Royce Creasey built a car engined (reliant) motorcycle, called a Quaser, that was a semi enclosed, Feet forward riding position deal that had hub centre steering around 20 odd years ago, somewhat earlier than BMW and Honda.
Hub centre steering does seperate the suspension and steering forces but give a very limited lock.
MZ had a bike that had a swing arm front end, looked appalling but actually worked very well, a system that has been employed by many sidecar firms as a retro fit for solo bikes being fitted with chairs.
Most of BMW's offerings are gimmicky and don't actually address the problem of seperating the forces and movements of suspension and steering.
RE: Alternative motorcycle front suspension systems.
RE: Alternative motorcycle front suspension systems.
Elf's centre hub demonstrated a weakness to the design, leaning into the swingarms often caused them to ground and resulted in a crash. Ask Ron Haslem how often he crashed from this.
Modern telescopic forks use coatings on the stanchions to reduce stiction, titanium nitride or "carbon like diamond", and decouple the braking effects from suspension.
RE: Alternative motorcycle front suspension systems.
RE: Alternative motorcycle front suspension systems.
IMO the ELF bike had a design flaw (comprimise!) in the front swingarm, but you're pretty well stuck with ungainly arms due to the angle of the wheel on full lock. Bimota have achieved the best looking solution to the difazio design although the Yam came pretty close. Can't comment on the Bimota from a riders view (I'm on an engineers salary).
RE: Alternative motorcycle front suspension systems.
The original designers seemed to want to limit a motorcycles pitch, and therefore weight transfer under braking; current racing front tyre design relies on this weight transfer to squash the tyre and increase the contact patch.
What we need to do now is review the various designs and work out what other benefits they brought..I would suggest a new variation of the Hossack design would allow full 'dive', but would not have any stiction, would allow tunable flex in the assembly and have better aerodynamic section.. (it cant be a lot worse than the two massive great outer fork tubes they are currently using!!)
RE: Alternative motorcycle front suspension systems.
Unfortunately he passed away a few years back.
RE: Alternative motorcycle front suspension systems.
Bravo Mr Crysz; now maybe the majors will try something (anything?) new...
Neil
RE: Alternative motorcycle front suspension systems.
http://home.mira.net/~iwd/2x2x2/intro.html
BTW The concentric sprocket swingarm deal has been out since the seventies, a British company called Spondon Engineering had that for public use utilising the Kawasaki straight 4 900's and 1000's
RE: Alternative motorcycle front suspension systems.
The concentric swingarm sprocket was done long ago as an idler for wider tyres than the engine normally allowed. The only detraction of its use here is the chain cannot be used to pull the rear wheel down into the road while accellerating giving less traction. Ducati has had a big problem with their swingarm bolted through the engine cases design.
The external front spring/damper unfortunately increases the metal required to enclose it instead of serving double duty.
RE: Alternative motorcycle front suspension systems.
I see little point in utilising the chain to "pull" the rear wheel down when to suspension could absorb the force and surely the drive chain is rotating in the wrong direction to do this.
RE: Alternative motorcycle front suspension systems.
Racing bikes have adjustable height swingarm pivots to allow this effect to be tuned according to rider feel during a race meeting.
The effect is like having a broken twig (the swingarm and pivot) and putting an elastic band round it (the chain), if the swingarm is straight there is no effect. if the swingarm is bent then the band will try to bend it more. Typical swingarms pivot centres are 7mm to 12mm higher than the output shaft centre
RE: Alternative motorcycle front suspension systems.
RE: Alternative motorcycle front suspension systems.
Now, what do you think of the Czysz front end..?
RE: Alternative motorcycle front suspension systems.
Must admit, I havn't come across the Czysz front end, got any links. This is getting interesting.
RE: Alternative motorcycle front suspension systems.
Good stuff..but I suspect there is rather a large gulf between some brilliant design thnking and actually racing Motogp.....
RE: Alternative motorcycle front suspension systems.
The suspension tube does not have to be round since it is not sealing in oil. Even though the track needs to be metal for the hardness, the surrounding shape can be made of anything such as carbon fibre to tailor the side flex.
RE: Alternative motorcycle front suspension systems.
RE: Alternative motorcycle front suspension systems.
The Tesi has Ohlins dampers front and rear, and provides nearly 100% anti-dive on the brakes. Stability under braking allows me to break later than others on the track, and turn in while on the brakes, a definite advantage.
However, the convoluted connections between the bars and tire patch compromise steering feel substantially, and the change in stiffness of the front end as the bike is rolled over (the front suspension uses a swing arm) does little to inspire confidence, especially over undulations and bumps.
Overall, I prefer the conventional front fork of the Supermono and Ducati. It's no surprise that MotoGP still uses a conventional but extremely well developed system that is well understood and highly tunable.