Road Cycling - How can I get my rear wheel centered better?

I have Shimano 105 9-speed cassette on my rear Mavic CXP 21 wheel. The frame on my 1999 Schwinn Supersport is built for this kind of set-up, but my wheel sits real close to the left (non-cassette) chain stay. Down near the seat tube, the tire has a couple of millimeters clearance from the chain stay. Is that normal? If not, what should I be doing to get it right?

Rich

Have your LBS check the dish of your wheel and the alignment of your frame.
OR:
Put your wheel on your frame backwards, (with the casstte on the left), if the wheel aligns differently it probably needs to be dished/re-centered. If the wheel aligns the same way, the frame may be bent.
To check frame alignment run a taut string from one dropout around the head tube and back to the other dropout and measure the distance from the string to the seat tube on each side. If the measurment is not exactly the same, your frame is bent, ( make sure the string is strung on the outside or inside of each dropout exactly the same way).
If you have horizontal dropouts vs vertical dropouts you may just need to adjust your "stop screws".

Ride Aligned
Pat

Pat has said it all. The only thing I might add is check the axel spacers to see there isn't an extra one on the drive side. This is a problem I have occassionaly seen.

Hey, thanks, folks for the help. Ther is a happy ending here. Did the two tests: wheel reversal and frame test with string. The frame is perfect. I followed the instructions in Zinn and the Art of Road Bike Maintenance and dished the wheel. It was a fairly easy job and I will ride aligned now. The lateral truing is fine but I have a small radial truing problem right around the valve area. Can't seem to fix that on my own. I'll either get help from a superwrench friend when he gets back in town or head off to the LBS.

Well, it's a bright sunny day and 75 deg here, so now it's time to get out and ride--aligned.

Thanks,
Rich