Moto2 Carbonfibre bike

[mycadcae]

carbon fiber composite chassis ...high cost?..

[mpower]

80's 250cc Armstrong carbon frame and rear fork

[Klaus]

Thats a really wierd looking rear(I guess) suspension on that thing!

Any idea on how that works?

[flyboy2160]

When Ducati was having problems with its composite frame, I hypothesized (uh...uh.....on another website) that although it's possible to tailor a composite structure, Ducati didn't know exactly what they were trying to achieve in terms of stiffnesses (in more than one direction). They may have just assumed "stiffer is better."

I suggested slathering a chassis they liked with strain gauges and then designing the composite chassis to the stiffnesses the riders liked. But, I'm not the Chief engineer there.

I recall reading that Honda and Yamaha have gone through such tweaking of their metal frames to get the desired stiffnesses. That same tweaking will have to be done with a composite frame, but it's usually much more expensive to do than with a metal frame.

[mpower]

Thats a really wierd looking rear(I guess) suspension on that thing!

Any idea on how that works?

its a sort of pull rod that runs through the cilinder

[Klaus]

Thats a really wierd looking rear(I guess) suspension on that thing!

Any idea on how that works?

its a sort of pull rod that runs through the cilinder

Got it! Can see how that all fits together now.

Thanks.

[Jolle]

I remember in the late eighties there were a few prototype carbon bikes in the 500cc. You also had the ELF Honda's with all kind of weird frame designs and carbon and magnesium wheels.

I think it was 88 or 89 when Cagiva made a 500cc carbon frame for Randy Mamola and after a few races the deemed it "too stiff" and nobody believed him... Because all frames up to that point already had some flex (because they couldn't be made better) and this frame hadn't. When the bike is on an extreme lean angle, the normal suspension doesn't work anymore and all suspension must come out of the flexing of the frame.

Another big problem, with racing, is the constant development. Prototyping a carbon frame takes time and because of the difference in flex, you can't just "carbonize" a aluminum frame. So with a carbon frame you're always a few weeks behind...

I think we will get productions bikes with a carbon or monocoque frame before it will get as common in racing like single seater racing.

[marcush.]

Thats a really wierd looking rear(I guess) suspension on that thing!

Any idea on how that works?

its a sort of pull rod that runs through the cilinder

It´s a through rod damper -the pistonrod is going stright through the bottom of the damper allowing them to pull directly on the damper ...
Yeti/Schwinn had this on their Lawwill DH bikes for some time ...maybe Mr.Lawwill holds some rights on that design?

[Tommy Cookers]

...... When the bike is on an extreme lean angle, the normal suspension doesn't work anymore and all suspension must come out of the flexing of the frame.

is there any authoritive opinion (a paper ?) on this matter ?
over the last 40+ years (including posting on this site) I have often said as much (as the above)
but .....
the machine lean angle is still only around 55 deg, the riders using more body displacement than ever before to this end
given modern low-friction bushes and lubricants, basic calculations suggest that the suspension does work

if we wish to engineer some structural behaviour that does some of the suspension's job
a carbon fibre structure has more scope for this than does a metal structure
metal is isotropic in its stiffness properties, carbon fibre (according its placement) allows suitably non-isotropic stiffness properties
that is tailored elasticity
it was used in the X-29 plane such that an upload on the wing produced upward deflection without twist
this would be impossible using a metal wing (part of the reason for the current composite structures ?)

[mpower]

sofar carbon chassis were not very sucessfull on motorbikes, same as u wont see a kart with full carbon chassis............ its not all about getting max stifness............honda used a pressure tranceducer on their headstock of the SBK chassis as feedback signal for the traction control

[tok-tokkie]

"Jolle" When the bike is on an extreme lean angle, the normal suspension doesn't work anymore and all suspension must come out of the flexing of the frame.

Czysz of America developed a 2 crank 4-cyliner MotoGP 990 bike which was made obsolete before it competed when the capacity was reduced to 800cc. One of the many novel features was the front suspension which had sideways flex designed into it for exactly this reason - so it could flex sideways to give suspension movement when the bike was leaned hard over.
Wiki just mentions that it had novel front suspension http://en.wikipedia.org/wiki/MotoCzysz
But the official site has something about it. http://motoczysz.com/motorcycles/c1_prototype
I don't know if it was carried over to their successful electric racing bike but it looks like it has been used.

[mycadcae]

more light...