Have a mini 17/42 bought last year. Has been awesome until today. I was mowing and thought I ran over something, stopped, smelled rubber and discovered it was my belt had fallen off somehow. I put it back on continued and it came off again and got somewhat eaten by blades. Put it back on and finished my yard and it completely broke. Now I need to replace it. What size is this belt? Also, is this an issue with mowing at about 2 1/2 "?