Thomas’ 20″ travel bike
Thomas asked me to build him a folding travel bike with 20″ (451mm) wheels so that it could be easily packed in a standard suitcase. He wanted a drop-bar light-touring type setup, with regular road gearing and clearance for 35mm tires and fenders. To accommodate that tire size with caliper brakes I built around a mid-reach TRP brake.
There aren’t many 451 carbon road forks available, and none with clearance for 35mm tires. So a Ritchey carbon cyclocross fork was cut down and modified with new titanium dropouts by my carbon-savy friend Devin.
The frame has my usual FRC pivots at the BB shell and rear dropouts. The coupling at the top of the seatstays is integrated into the seatpost clamp, securing the stays and the custom titanium seatpost at the same time. A special brake mount allows the caliper to sit on top of the chainstays and be clear of the chain.
At the front, there is a custom carbon stem riser, topped by a custom lightweight ahead stem. The parts feature White Industries hubs, Shimano Ultegra and a Turn crankset.
Thomas also requested some custom bags, which were made by Blaqpaks in Portland. The frame bag bolts onto bosses brazed on the inside of the triangle, and features a clear map pocket on one side. The rear bag mounts to the top of the seatstays, the seatpost and the saddle, and has rigid reinforcement inside to keep it stable.
The bike packs quickly and easily into a Samsonite suitcase for straightforward airline travel. Total weight is just over 17lbs.
Hi Rob!
I was always wondering how is the geometry for a small wheels bike. Is it the same as it would have larger wheels? meaning same BB to front wheel and same BB to rear wheel (horizontally speaking), same seat and head angle, same trail? If yes, then the only change would be in the fork offset, a smaller one to get back to a good trail dimension, right?
Cool bike!
Best regards,
Mircea
Hi Mircea,
Yes, geometry ends up very similar, just with adjustments to headangle and fork rake to give the correct trail. Then it just rides like a bike, and you can forget that the wheels are smaller!
Best regards,
Rob.