View Single Post
Old 01-14-2010, 11:50 AM   #10 (permalink)
Bicycle Bob
EcoModding Apprentice
Bicycle Bob's Avatar
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,688

Appliance White - '93 Geo Metro 4-Dr. Auto
Last 3: 42.35 mpg (US)

Stealth RV - '91 Chevy Sprint Base
Thanks: 84
Thanked 397 Times in 277 Posts
A standard bike frame is designed to be inherently light and rigid. Since nothing is perfectly stiff, there is some flex, which the manufacturers say they added for comfort, trying to have it both ways. A bike with long suspension travel and soft springs is a major revelation to ride. It can still be simple and elegant, and far more comfortable if laid out as a recumbent, so that the necessary rigid connection from seat to pedals is at right angles to the flex on bumps. Most of the wooden frames are pretty, but rather appalling, structurally. On a classic frame, the highest stress is on the down tube, where it resists the rocking of the bottom bracket, yet many artists eliminate this part completely. It takes great skill in pedaling to avoid wasting the energy that produces flex.
I designed and built a recumbent trike in which just six fiberglass parts provided seat, frame and a very sophisticated suspension. Only the dampers needed to be separate parts. I'm interested in doing it over using mostly wood. The Car Cycle
  Reply With Quote