Wow, just have a look at those chain stays. This bike was build by Trevor Jarvis and is an exact replica of a ’53 SBU Tracker. It was built with the intention of a achieving a stiffer rear end and BB area – better suited for velodrome racing and sprinting.
Photos and story via Classic Cycle US
The original SBU bikes are a bit of a rarity, with only seven bikes ever having been produced. The radical design of the chain stays was meant to produce a more stable, and at the same time a better sprinting, bike for the velodrome.
The reality was that the bikes were a bit whippy when sprinting out of the saddle.
More shots below