I've converted the BOKOR to a 650B Mtb Fixie. I gave it a ride this evening as the sun dropped. Definitely a different ride style. I had a few fixies years ago. One was a Surly Steamroller that I toyed with as an off-road fixed. I built this wheeled using the SUN cr18 650B. As some have posted the tire fit pretty tight, but went on similar to a tight fit with some wire bead tires. I've dealt with worse, that for sure. 39x15 gearing. I kept it to the local gravel levy, paved roads to get there and grassy, rocky levy climbs.