Tuesday, December 29, 2009

Al'turn'ative Tuesday

Will the 6X Flex front-end be used in Moto2 this coming year? It has been adapted to an Augusta and a Yamaha R1 during development.

patent document

The new class (which requires every bike to use the same Honda motor) can be very interesting for those who like chassis design. This could be an opportunity to see alternative front suspension systems....

The following text & images are from Road Racing World's good article on the Moto Czysz C1 racebike. (September 2006)

"The fork tube is firmly attached to the lower oval sections of the fork like a traditional inverted fork. Telescopic forks slide up and down on oiled bushings that, by necessity, have a bit of play in them. This play introduces a bit of slop into the fork action. Also, when braking, the forks can bind on those bushings. Really good forks, of course, have less slop and less tendency to bind. The Czysz sports diamond-like-coated titanium fork tubes with flat sections on them. The flat sections match linear roller bearings (imagine a ladder where the ladder rungs are roller bearings) in the upper part of the fork. These bearings positively orient the fork making it so cannot bind no matter what forces are applied to it. The damping and springing action of the fork is contained by a single Ohlins unit mounted to a bridge between the sliders. The arrangement eliminates variations between the tune on each fork leg and also allows for the complete replacement of the valve stack and spring in a few minutes through a simple external swap of damper units. Lastly, this damper is already gas-charged preventing cavitation of the damping oil. No leaking fork seals, either.

Instead of flex in the frame the C1 has suspension components (forks and swingarm) that are designed to be rigid in the suspension travel directions (up-and-down and back-and-forth), but flex laterally to absorb bumps from the side. This is done in the rear with a swingarm that is extensively braced top to bottom but with a little give side-to-side. The flex in the forks is provided in the lowest portion of the fork leg. The large section front-to-back resists deflection during braking but the thin section side-to-side allows the fork to soak up bumps at full lean. At least that is the theory. The big oval in front of the brake mount is for the axle insert."

The C1 uses a very rigid Carbon Fiber frame, so the idea is to keep things solid in the middle and control any flexing at the ends, closest to the wheels & contact patches. The axle insert mentioned above is also said to allow quick adjustment to trail while keeping rake constant.

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