[Pat Fairbank]

We used timing belts to drive our robot last year (4 wheel drive, 2 motors per side). We had 4 sets of belts on each side between the motors and the wheels, and we discovered that in some places belts work well, while in other places it would be better to use chain.

For example, the belt connecting to the front wheel was the longest and had the most torque being transferred through it, and it tended to either snap or strip itself to uselessness when push came to shove in a match, no matter how much we tensioned them. We ended up switching to #35 chain for just that section. On the other hand, we never had problems with the relatively short belt connecting the two motors together.

To sum up, here are what we found to be the pros and cons of belt drive:
Pros:
- belts are lightweight compared to chains; also, you can get by with aluminum pulleys which tend to be lighter than steel sprockets
- they come in fixed lengths, so no fiddling around with links and half-links
Cons:
- belts tend to strip or snap in high-torque situations
- replacing belts during competitions is time consuming since you can't just join the ends together like with chain (we got around this by looping several spare belts around the shafts and zip-tying them out of the way)
- they have to be really well tensioned so as not to slip/strip (chains are much more forgiving)
- belts tend to slip off their pulleys if not well aligned, unlike chains

I hope this helps you out.