Quote:
Originally Posted by Arpan
Personally, I love #35 chain over belts because chain does not have to be as precisely tensioned and most powerful (4 or 6 CIM) FRC drive applications are actually a little out of spec for either HTD 5mm belts or #25 Chain.
|
To provide some counterpoint:
I have seen a grant total of one belt failure in my 7 years in FRC (out of 4 years of belt drives), on a belt that was overtensioned, at an offseason event after several competitions. Both 4464 and 449 ran belt-driven 6 CIM drives last year without incident (modified KOP on 4464, 9mm belts on 36-tooth pulleys in a WCD on 449).
I have seen more chain failures than I can count, mostly due to master links or slightly out-of-alignment sprockets.
Thus, I can't honestly say that I wholly buy the robustness argument for chain over belt. As far as failure rates go, my observations are precisely the opposite. Belt is far more forgiving in terms of alignment slop between the pulleys, and if you don't have the machining capabilities to have exact C-C distance you can do fine by having one end of the belt run be adjustable (versablocks are a great way to do this). The lack of stretch means that you need less adjustability than a comparable length of chain, as well.
The only downside I've ever noticed for belts is that they demand that you pick a length and stick with it, so there's little potential for last-minute design changes (unless you purchase a new belt). In a drive, this isn't so much of a problem - frame dimensions are usually decided on very early and seldom changed.