I realize there are previous threads about this but I felt compelled to start a new one and share my recent experience. I have a 36" Scag walk behind that is belt driven. I don't use a velke. I use the mower for the steepest of hills that my stander will not mow. At the beginning of this season I took mower out, it wouldn't even pull side to side on hill at all. I had to put it back on trailer and weed eat the lawn I was working on. I immediately got online when I got home and ordered belts ( mainly cause the idiot Scag dealer wants $75 per belt and I can get them for $20 online ). After getting on here and reading some threads, some people had said to try belt dressing first. I don't really much believe in lightning in a bottle of any sort but I figured what the hell, it's too cold to mow today anyway, why not? I jacked up mower with the drive wheels off the ground, put it in gear, and soaked both sides of both the inside and the outside of the drive belts. I set mower down took it to the steepest hill at the shop. It pulled the hill even when I tried to hold it back. This is just one more time this site has proven itself. I am extremely thankful for this site and all the information that is available.