Tuesday, August 26, 2008

Old Fat & Slow Gear Vol. 10 - Spokes

Ever spent much time thinking about bicycle spokes? If so, then you really need to get a life. Spokes are nothing more than a piece of wire, mashed and bent on one end and threaded on the other.

I was out riding yesterday morning when I started noticing a toink, toink, toink sound coming from the rear wheel. Apparently, I had kicked a rock up and broke a spoke on the non-drive side of the wheel. That evening I stopped in at REI, with my broken spoke and asked for a couple of new spokes. What I got in response was, "If you're breaking a lot of spokes, you really should have that wheel looked at." I said in return, "I'm not breaking a lot of spokes, in fact I think this may be the first spoke I've broken in 40 years." I didn't feel like I needed an upsell of wheel maintenance, since I do all my own wrenching, and wheel truing is something I do pretty well. Anyway, I got out of there with 2 new spokes and my broken one for 2 bucks plus tax.

Since the broke spoke was on the non drive side of the wheel, I was able to thread the new one in and tension it without even removing the wheel from the bike. To do that, it's necessary to bend the spoke (hey, its just a hunk of wire!) into a gradual arc and feed it through the hub. The bend allows the spoke to slide in without interfering with the cassette. A little straightening and feed it into the nipple. Tighten, check for true and off you go.

I don't have a tension gauge for truing. I use the harp tuning method; pluck each spoke as you work and try to keep all the spokes on each side at about the same note. B flat above middle C works well. On the front wheel, both sides will come out the same. On the rear wheel, drive side spokes are shorter, so the tune you play will generally be a little higher. Transpose it to a key of A.

Basic rules of thumb - If the wheel flops around the spokes are too loose. If the tune you play on your spokes sounds like anything above a mezzo-soprano, they're too tight. If you have carbon fiber wheels and the spokes are large enough to have decals, you spent waaay too much money.

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