I recently replaced the entire drive train (ie. chain rings, cassette, chain) of my old steel road bike, which has a shimano 105/600 mixed group (14 sp). While I did this work, I also serviced my rear hub (early 90's 105), replacing the bearings in the cups as the were showing some wear. Initially the shifting action was clean and lovely, the ride significantly smoother. However, about a week later the chain started to skate (that is, ride on top of the teeth) for the middle 3-4 gears on the rear dérailleur. This didn't happen all the time, but it seems to be worse when under stress (crank up grades and such). When trying sort this out, I realized my rear axle had become loose, which was odd, so I tightened it up, and that seemed to sort everything out. It may be worth noting here that my rear cassette shows a bit of swim (that is, side to side wobble as the cassette rotates), sort of the higher end of tolerable, but I wouldn't figure that to be the issue.
So, figuring everything is fine, the next day after I changed the tire (routine maintenance, no massive failure, tire was just worn out), the skate was back, though the axle was still reasonably tight. As this is my primary commuting bike, I've ridden it a bit in the week since out of necessity (a handful of gentle miles) and the skate has worsened and it appears the axle is now loose again.
Anyone have any idea what is going one here? Any and all theories appreciated.
Update: So this weekend I went to my local co-op bike garage (the awesome London Bike Kitchen) and determined a couple clarifiers: a) my axle wasn't loose, I was just a bit paranoid b)the shifter cable was, at the rear braze-on was. My frame apparently dates from before the days of shifter cable housing (ie. brake cable housing everywhere) so this braze-on is slightly to big for the cable, and the shop that replaced the cable and housing jerry-rigged a holder, which no longer worked. So my shifter cable didn't have a stable angle of incident. So it wasn't so much that I was skating as I was never properly in gear. We rigged a mostly half decent fix for now that involved a cable tie, but if anyone else knows of way to get sti cable housing stable in a brake housing sized braze-on, I'd love to know about it.