Well, as I sit here ready to submit our order to McMaster-Carr, I am wondering if we should get some different round belting. We have the clear belting right now, but we are having problems with it stretching and popping off. The other option on the website is yellow belting, and I was curious is there is a difference in the elasticity and also the ‘grip’ of the belt.
Thanks one again, you guys are so helpful and have made our first year a successful learning experience 
2815 used clear belting this year (as seen in my WAI). On occasion, it does pop out of its groove on our rollers–but we’ve got six such belts on each segment, so it’s something we can survive until we get the robot back to the pits. The net result is a rock-solid system.
Can you describe your system, or give us pictures to show where things are going awry? (I wouldn’t wish having to weld a bajillion more belts on anyone…I think I’m just now getting over the fumes.)
How much are you stretching the round belting before you put it on?
You should measure you size and take off at least 7-10% of that length and join the tubing. Then stretch it on…
We are using it and haven’t had any problems with it falling off…
We did run it for awhile and then took off an additional 4 inches from each belt before we shipped… our belts are something around 9-12 feet long…so this was an additional 2% in addition to the original stretch.
We use the orange belting which is pretty much identical to the clear.
We had some good luck with the orange material.
We got ours from Grainger - they offered to import more for us from India… I think it was going to be 20$/50ft (pretty cheap)… but I can try and find the exact quote for you.
what size belt and roller are you using? there are some recommended minimum sized rollers for different diameters of belting.
we are using 4 different sizes of the 3/16" clear from McMaster-Carr
each size is aout 8% smaller than the actual measurement and so far they have not jumped the grooves.