I recently replaced the blade drive belt on my riding mower and it broke after 3 hours. I checked for anything that would cut the belt, found nothing, and installed another new belt. After engaging the blades for 20 seconds I stopped and checked the belt and noticed it had twisted. This happened on my first reinstall, too. The belt is not loose and there are no obstructions. I think perhaps the new belt is slightly more narrow than the original.

I assume the belt should not twist? What is making it do this? Anything else that could be breaking my belt?

Thanks

Have you checked your pulleys to make sure none is bent. Did you check to make sure new belt is same width as original? If this is a 48" deck it is best to put deck in lowest cutting position and engage blades to "burn" belt for a few seconds to keep from throwing it. May I as what brand this is on?

Thanks for the answer. This is a Sears mower. The pulleys aren't bent, but the new belt is slightly more narrow than the original. I thought this was suspicious. I'll try another store. Thanks again.

Replaced drive belt on my husky riddidng mower (46'' cut) about 2 weeks ago, know it's messed up again. I smeel rubber burning and is starting to pull on it's own. What could be the problem?