Actually no, it does have other benefits. I've done it to my tyres too, apart from saving weight (its saves hardly any though), they tyres shed mud more efficiently and also (I'm taking bessell's word for this) they grip better. I couldn't tell you if they grip better or not because I swapped from Schwalbe to a Maxxis, hacked away at the Maxxis before I'd even ridden it. But what i can tell you its that it grips very well how it is. Edit: Did you actually cut off all the nobs on your rear tyre? If so, the word used to describe you above was probably accurate. They cut every other nob on the outside rows of their rear tyres. Any more than that and you must have a death wish. I think Giacomo Coustellier might have cut all the tread off his front tyre (bit daft IMO)