My rear wheel is in the shop so I borrowed a friend's. Problem is, my bike has 8-gear shifters (the kind with thumb triggers and numbers) and an 8-speed 12T-34T cassette, while the borrowed wheel has a 7-speed 11T-24T cassette. It was the best I could do on short notice. Both wheels are 700c / 28 mm.
I tinkered for quite a while with the high and low limit screws and the fine tuner thingamabob. My initial approach was to lock out the "1" gear and adjust to where gears 2 through 8 matched the available gears on the casette. Then I switched to locking out the "8" and matching up with gears 1 through 7. For whatever reason, I couldn't get either of these approaches to work at all. The shifting was horribly erratic.
Finally, I managed to get it set up to where the "1" setting fits nicely into the biggest rear gear, and the "8" setting matches up with the smallest rear gear. The shifting is smooth enough, but the shift from 3 to 2 doesn't do anything, nor does the jump on the way back up from 1 to 2. In essence, gear "2" is MIA in the gap between 1 and 3.
I am heading now to pick up the repaired wheel, so the issue is moot. But I'd like to know whether there is something I could've done differently (other than buying a spare wheel or borrowing a wheel from a different friend!). Might chain length be part of the issue?
Also, I'm curious whether what I did might have caused any damage to the wheel, cassette, derailleur, etc.