If anybody wants to try this out it worked out well for me. My rear tire was becoming distinctly square from all my highway commuting so I decided to do something about it. I found a thread online detailing the process and gave it a try. In a nutshell, I put my bike up on the rear stand and used a Stanley Surform tool ($10 at Home Depot) to shave the high spots on the rear tire while it was spinning in 1st gear. I shaved off just a little bit of rubber (surprisingly little) and voila! It has a much rounder profile now and the tip in seems easier (though I also upped the pressure from 30 to 35psi at the same time). Cheers.