Sunday, September 25, 2011

FS 69er Concept

Just a small pause in the serie of posts dedicated to the pedaling motion to show this bike concept. I designed it during the year 2010 and it was finished by the end of August, before the Eurobike 2010 took place in Friedrichshafen where some of the "innovations" of this concept were presented (Hope's cassette with a 9t cog e.g.). The aim was to design a really light FS XC bike, as simple as possible, inspired by Cannondale's Zero Pivot system. As many of you know, a softail system isn't the best on from a suspension's performance standpoint but its simplicity allows very low frame weights. I really think that this system combined with a well studied pivot placement for a concrete drivetrain configuration and a platform shock could be the definitive weapon for XC racing. Some of the highlights of this concept are:

- Full carbon softail frame designed for 29er front wheels. BB30. 29er front wheel gives the main benefit of 29er bikes without many of their problems. 70.8º head tube angle and 73.8º seat tube angle. 1.125-1.75" tapered headtube. Vertical seatpost tube that allows shorter chainstays, a lower standover height and good mud clearance without the need of a ST-TT reinforcement. ISP. Syntace X12-142 axle system make the rear end stiffer and allow the chainstays to be wider in order to increase the lateral stiffness of the rear end. Shock mounted perpendicular to the rear axle to reduce the lateral loads that it has to handle. Integrated front end to reduce as much as possible the stack height. PostMount caliper fixing system.
- Stem with adjustable angle to allow any stack/reach value.
- Single sided 29er fork. 1.125"-1.75" tapered head tube. 480mm A-C length. PostMount caliper fixing system. 51.2mm fork offset to reduce trail as much as possible. Result: 73.8mm of trail, the same as many of the current 26" XC racing bikes.
- 32t chainring combined with a 9-34 cassette. Just a gear shifter.
- Tubular rear wheel to increase rear wheel traction, one of the weaknesses of the suspension system chosen.

And finally, some pics of the concept. Comments are welcomed

More soon. Thanks for reading!

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