We used nylon sprockets on our prototype over the fall. The prototype used a fisher price and a CIM motor on each side of the robot in a six wheel drive configuration. We used AMshifters to give us a top speed of 10 ft/sec in high and about 4 ft/sec in low (off the top of my head). I don't have the torque numbers in front of me but I would say it is comparable to any sort of forces most teams would see on their drive train. We bolted nylon sprockets on the four corner wheels (less load than the center wheels usually). We had 180 degrees of tooth engagement on the sprockets which were 30 tooth and 35 pitch. After a lot of hard testing we had no problems with these sprockets. Not a single tooth was broken and there wasn't any excessive wear. We are not sure if we had any efficiency loss from the nylon sprockets yet,
Note: In the end we decided to lighten steel sprockets for our drive system just to be safe.
If your really trying to save weight I would look at nylon or aluminum sprockets. We bought the nylon sprockets (part number 6793K135) from
Mcmaster-Carr. We also have bought aluminum sprockets from a local supplier for
Azusa . These sprockets are made for go-karts and look really good and strong.
Hope this helps,
Good Luck!!