Thursday, October 9, 2008

Crank Forward Number 3




The no weld crank forward was fairly successful but I decided to try perfecting the bike with some cutting and brazing. The original bike was an old High Sierra Schwinn mountain bike. One of the more serious shortcomings of this rendering of the bike was its tendency to pop wheelies on takeoff. The seat sits almost over the rear axle. The bike did not handle badly but I figured sooner or later I would forget which bike I was on and end up being dumped on the pavement.




My plan was to stick pretty close to dimensions on one of RANS new models they offer taller riders called the Sequoia ( http://www.ransbikes.com/Sequoia.htm ). Wheelbase on crank forward number 3 came out 53". It is very stable and comfortable. I'm still messing with the handlebar setup--I have a set of RANS B38 bars I may try on it. I plan to paint it dark green similar to the original mountain bike's color--the fork will probably not get repainted at all.
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Crank forward bikes are considerably simpler to build than recumbent bikes as the origingal steering angle and bottom bracket position can be retained thus eliminating fork bending and cutting on the down tube. Basically the seat ends up about 6 or 8 inches back and the chain stays are extended about 7". I keep about 5" of the old seat post for mounting a front derailler and attach a new seat tube to the base of the old one and angle it back at something closer to 50 degrees rather than the original 70 degrees. Mountain bikes seem to be better suited to conversion into crank forwards but I think an old road bike could be cut up for this purpose. Crank Forward bikes make great commuter bikes and city cruisers whereas recumbents are probably a better choice for longer road trips.