Thursday, January 13, 2011

Fixootr

Work had me ridiculously busy and rather stressed from late November until the end of the year. While I didn't have adequate time to begin or resume any full-fledged bike builds or other major projects, I did find that I could wind down and relax a bit at the end of my hectic days with a few minutes of wheel building. I had accumulated a few low-to-medium priority wheels to build, so this was a good way to avoid falling too far behind.

Wheel #1 was a composite affair. El Prez had a 700c flip-flop wheel on a Motobecane setup as a fixed-gear and a new 20" Weinmann BMX rim laced to a faulty coaster brake hub. Both wheels had 36 spokes, so I was tasked with mating the Quando flip-flop hub from the big rim to the the 20" rim by any means necessary. The resulting Frankenwheel would be destined for his Xootr Swift folding bike.

There were a couple of issues with the Quando hub. Firstly, the bearings were kind of shot. Secondly, it was meant for a frame with 120mm rear spacing-- fine on the old Motobecane, not fine for the 135mm rear spacing of the Xootr. The Xootr has an aluminum frame, so cold-setting is out of the question. A new set of bearings made the hub much happier about spinning. A round of spare parts scrounging at Maison D'Interstatement turned up a longer axle and a spacer/locknut combo that added up to 135mm.

The hub was ready to go, with a caveat: since most of the extra spacing had to go on the left side of the hub to maintain a straight chainline, the wheel is no longer symmetrically dished and effectively can't be flipped around for use with a freewheel. Neither of these things are deal-breakers in this case. I think the inherent overbuilt strength of a 36-spoke 20" wheel should more than compensate for the weakening effect of an off-center dish. Prez was only interested in the fixed-gear function of the hub, so he wasn't bothered by the loss of freewheeling capability. The best way to see how it holds up is some vigorous real-world riding of the sort that its owner is both qualified and inclined to dish out.

The spokes are Wheelsmith 2.0 mm, with DT Swiss brass spoke head washers making for a snug fit in the hub flange. I used UBI's online spoke calculator for the lengths. As of this writing, the wheel has been in use for several weeks and El Prez is pleased with its performance. This was my first time building a 20" wheel and I liked it for it's compact, manageable "laptop" size. There are a lot of neat hubs besides fixed (internally-geared, dynamo, drum or disc brake) that are rarely built into this configuration, and I'd like to see more. There's a lot of potential for folding bikes to become more useful and fun for more people.

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