Fussing With Gear Inches

I finally ordered a set of cogs off of eBay. The guy was selling 7 cogs and my bid of about $12 won the shootin' match. The sizes are 20, 18, 17, 16, 15, 14, and 13. I put the 15 on the Centurion, which has a 50T ring (actually, both bikes have 50s), requiring breaking the chain and removing a link, struggling to get the wheel on enough due to the shorter chain (should have used a half link), fixed the slow leak in the rear tire, and went for a ride.

The 15T is a definite improvement over the 18T I replaced. The 18 required too much spin on the flats and downhills. I still have a 16T on the Bianchi. The 50/15 gives good speed on the flats, and helps keep the downhill spin under control with less braking, particularly compared to the 18T. The 50/16 on the Bianchi allows me to stay in the top gear much of the time, with the occasional shift at the stop. I almost never shifted with the 50/18. The 15T requires more shifting, and I've been using the lowest gear more than previously (which was almost never).

This seems to me to be sensible, because I was riding much like I was still on a single speed fixie with both the 50/18 and the 50/16, usually only using the middle gear at a stop sign, and the low gear rarely. Now I'm still  in the top gear a lot, but I'm shifting down for moderate climbs and way down for the steeper stuff or when the headwind is fierce. I think 50/15 might be the best compromise, but I'm not going to stop just yet. I'm going to try the 14, then the 13.

I preferred riding the Bianchi until I switched the cog out on the Centurion. I wasn't sure why, but it seemed to take a bit more work to ride the Centurion. Now they seem about equally enjoyable to ride. I thought the Centurion was heavier or the fit wasn't as good as the Bianchi, but I suspect that the gear inches were the difference.

BTW, I tried to readjust the endplay on the axle to see if some of the lash on the black Alex wheel would improve, but I can't get it to be as good as the silver Open Pro wheel. Maybe the black one is an earlier run, or the tolerances aren't consistent. I know the earlier hubs had lots of lash, and it improved in subsequent batches. The difference in lash makes a difference in performance. I don't trackstand much, but the two wheels are a very different experience when I do. Also, the pedal bump is significant with the black one, and I find it a bit annoying on a fast downhill. NBD.