155c transmission

[bertsmobile1]

did you measure your new belt by your old belt? old belt has probably stretched over time and if you used it to measure for another belt, the new belt would be too long.

Mower belts do not stretch.
They wear on the sides so go deeper into the pulley which is of course a smaller diameter and thus become slack.
In fact a lot of belts actually shrink when they get hot.
So measuring the old belt is a suitable method for deciding which length of belt to fit.
Next time you remove an olf belt, have a good close look at the wrapping.
You will see it is still quite square.
If the belt was stretching the cover would also stretch so would appear to be rectangular weave and not a square one.