Freaky front tire wear: Unusual front tire wear (a wavy look to the front tire blocks, called cupping) may be the result of improper inflation, but it can also be caused by a front suspension problem. This may be a damper or spring problem, but it could be caused by binding as well. If you have changed front fenders, added a fork brace or fender rail, or assembled the front end without aligning the legs, there may be pressure in the fork assembly that causes the problem.
If you replace the front tire, most tire manufacturers insist that the rear tire should be replaced at the same time, though the reverse is not true. Instability may result.