Hi, I put back on my rear wheel after switching the cassette. When I shift down it goes to the 4th cog after being on the 1st and now it won't go anything smaller than 4. Did I do something wrong when reinstalling the wheel? And what can I do to fix it?

Thanks

maybe a cable housing piece has not settled back in the frame stop, where it belongs.

Too many possibilities. It would seem that something about the cassette you switched, or how you installed the wheel is a factor (assuming all was normal before the change), but without more info it's hard to say where. More details and a photo would help.

This can also happen if the wheel isn't seated completely in both dropouts. Easy to check

https://farm6.static.flickr.com/5251/...f28e17d5_b.jpg
The cassette is the same, I changed the wheel
I installed the wheel the same as I've done in the past: shift to the smallest cog, remove, reinstall in the smallest cog
No cable housing piece was missing
I re-taut the RD cable and was able to shift higher, but now it mis-shifts between 2 and 3

try adjusting with the adjustment barrel on the derailer, in the photo it look like you can turn it in a little.

OK now we're getting closer. The cassette to right dropout distance varies slightly hub to hub, and among brands of cassettes. That means when you change wheels or cassettes, you have to recheck the inner and outer limit adjustments and the trim (cable tension) adjustments. Often the difference is slight enough that the limits are close enough, but the trim is very sensitive to any shift in cassette position.

If you have multiple wheels for the same bike and switch back and forth, for example training, racing and time trial wheels, it pays to get or make some micro-spacers for behind the cassette and get the cassette to locknut distance identical on all the wheels. Years ago I sponsored a team, and we carefully matched all the wheels so any wheel could be moved to any bike without any change in RD adjustment.

That was my first thought.

So check the high and low limits by adjusting the limiter screws?

So i've watched this video https://www.youtube.com/watch?v=2j1gSwhsVN8
I got the high limit aligned but it mis-shifts when downshifting 1 gear after the smallest. the video says to adjust the tension with the barrel adjuster. but my barrel adjuster seems to not do anything when i turn it. what could be the problem this time?

thanks for all the help, i really appreciate it

Note that the barrel adjuster will (or should) not affect the position of the RD in high gear, where it's resting against the limit screw with the cable slack. Shift to the second position on the lever, and hopefully the RD will shift to the second sprocket. If not back out the adjuster until it does.

Now adjust the barrel adjuster while watching the RD from the back and you'll see that backing the adjuster out tightens the cable and moves the RD inboard. You want the RD centered on the sprocket (the chain runs quietest). Once you adjust it for one sprocket (except high) it's set for all of them.

Now shift through the range, and fine tune the adjuster so that the shift response is equal on up and downshifts and all gears shift crisply (this is usually within 1/4 turn on either side of where you centered it earlier.



Now shift, to