Tank Tread Help

[Jstack14]

We are in need of some help...

We are making a robot that is about 3.5 ft. by 2 ft. wide. We are going to put some sort of tank tread on it but what we currently are using is not working. Currently our tread is two lines of chain that go around two sprockets each. They are connected with strips of Lexan that are riveted into the chain every fourth link. On the sprockets every fourth link is cut off so that the rivet pieces of Lexan line up with the cut out teeth on the sprocket. This system would work, but all of the holes on the Lexan pieces don’t line up, so the chain slips off often and then it simply doesn’t work. We are wondering if anyone has suggestions how to fix this, because if we can’t fix it we will have to come up with a new idea. We are thinking timing belts and pulleys, but we can’t find any that are wide enough. Does anyone have any suggestions on how wide the belt would have to be to be effective, and where we could find a fairly affordable belt that size?

Or are we approaching this entirely wrong?