I have a Quinton Q55 that is at least 15-20 years old. It was purchased from a physical therapy department in a hospital. It is the same treadmill used for stress tests. It has been a great treadmill for many years, but now the belt needs to be replaced. I started to look at how to replace the belt and it appears that I have to completely remove one of the sides. The belt goes around a welded frame. If anyone has any ideas please let me know. I have taken some pictures and can post them if necessary. I did speak to a local treadmill repair guy, after looking at the pictures he said he would not touch the repair with a 10 foot pole.