Wednesday, February 22, 2012

Crank Forward number 7



Crank forward number 7 is based on a Huffy mountain bike frame. I think I picked this frame out of a junk pile but if I bought it I didn't pay more than $5 for it. My first plan was to make a cheap single speed campus bike and try to make a small return for my work by selling it on Craig's list. I wanted to try a little less offset of the seat to bottom bracket than my previous CF bike to improve hill climbing and stand up pedaling. The resulting frame has a wheelbase of 46 ", rear stays at 22" and a seat tube angle of 56 degrees. There is still enough crank forward to get both feet on the ground with proper leg-to-pedal adjustment but just barely. The resulting bike seems pretty responsive for a cheap iron Huffy. The rear triangle is short enough that the front wheel is pretty easy to loft making for good curb hopping as a city bike. I had the original single speed gearing set at about 50" by using a cluster with a 20 tooth gear and a chainring of 39 teeth. I liked riding this bike so well I decided to see how it would do with a wide ratio 5 speed setup. I used an old suntour 14-32 cluster and kept the 39 tooth chainring and the result is 5 very usable gears.


I used the wire welder in building the handlebar riser and seat post mountings as well as for tacking small parts in place for brazing. The .035" self fluxing wire would be too much for a nice thinwall Cro-Mo bike but the old Huffy frame is pretty good for mig welding practice. I used dollar Wal-Mart flat black paint on the frame and the result is pretty good for so little prep work. I like being able to go back and touch up spots where I've added braze-ons without having to repaint the whole frame. Sadly, our local Wal-Mart doesn't seem to be carying the dollar paint in flat colors any more.


My next project may be to make a fold down version of the handlebar riser so the bike will fit easier into my van. I'm thinking that if it folded forward, you could turn the front wheel back and the whole bike would fit on a city bus rack like a standard 26" cruiser bike. Then, maybe add a couple hinges to the frame and make it fit into a compact car trunk like CF1 does...