roth rothar I commute in Colorado where goathead thorns are prevalent. Before getting tire liners I was patching flats about once a week (now it's about once a year...if that) That's a lot of on/off and the tires, always inexpensive ones, didn't suffer. This was true for my 26-incher and then my 700C bike.

For the last five years I have mounted, unmounted and remounted snow tires on my 26-incher for snow season in the spring and fall with no problems.

However, I just bought a set of used rims at the bike co-op this summer...$40 for the pair. With some practice and adjusting the wheel-swap now takes just under 5 minutes including the brake adjustment, instead of the 30-45 minutes to swap tires.

If you can find cheap wheels in your budget, it may be worth it, provided the wheels are in decent shape and compatable with your derailier and chain.