Originally Posted by
defiancecp
So I'm a newbie and I got one of the new varsity wal-mart bikes.
OK, you got one of these bikes:
http://www.walmart.com/catalog/produ...uct_id=4698938
Dang... that's really different from the 40 pound Varsities I worked on 30 years ago.
In any case, the cassette wobble you're describing is actually fairly normal. I've seen it on lots of bikes- more expensive bikes have less, but it's still there. 1/4" is a little excessive, but if the bike shifts properly and stays in gear when you want it, why worry? In most cases you can't adjust this out.
I'd be willing to bet that the hubs and cassette are Taiwan-made cheapies. Usually, they try to match Shimano's dimensions, but it sounds like that's not the case. Look really closely on the hub and cassette for a manufacturer's name- something like "Joytech" or "****eng" might be there. That may give you a starting point for finding a cassette tool.
Once you have the tool that fits, the Park Tool site has some great instructions on how to work on your bike. Here's some articles that will get you started:
http://parktool.com/repair/readhowto.asp?id=48
http://parktool.com/repair/readhowto.asp?id=45
http://parktool.com/repair/readhowto.asp?id=105