Over time the rubber stretches with age, and loses it's mojo, the best solution is to simply replace it with a fresh one.
There are two belts included in each pack.
Please take note of the brand of drive inside your original xbox as there are some differences to be found.
You can use these belts with Samsung and Phillips, but not the Toshiba drives as the belt size is too different for these to fit.
These belts are smaller than originals but stretch over the wheels to fit with a better tension.
