Seth Rosko’s 650b Single Speed MTB

The problem with going to New York City is that I spend more time photographing bikes, then I do actually riding them. Which, in this most recent trip, wasn’t as much as I’d like. Being behind a lens, staring down a unique beaut like this does have its merits. Especially when you’re so familiar with its builder and owner.

Seth Rosko was one of the first builders in Brooklyn that I spent a good amount of time profiling years back. We first met at Brooklyn Machine Works, where he was a designer and fabricator. He and Joe worked extensively on the Gangsta track back in the day, before setting out on his own.

Rosko builds unique, yet utilitarian, yet lightweight bicycles made for racing. Each year, more and more fledgling racers find themselves on a Rosko and that means that Seth has less and less time to work on his own bikes. Case in point: this 650B single speed MTB. It took Seth years to finish this bike but he managed to complete it in time for this year’s season.

Using the ultralight True Temper Supertherm tubing, Black Cat dropouts and Stan’s tubeless wheels, this thing is light. It comes in at 20 lbs with XT pedals.