[Chris is me]

Originally Posted by Rauhul Varma

I'm sure many on 971 could have a long discussion with you about the strengths and drawbacks of the HTD vs GT Series belts. IIRC they ran GT3 belts in their drivetrain due to the shock the belts experienced with their high CoG. (Take that with a grain of salt as I did not look at their robot too much this year)

I personally go with GT2 in every application as I have yet to find a place where they don't 'just work.'

(here a link on htd vs gt2)

This is something my team has gone back and forth on as well. Our first belt drive had several failures and was done with 9mm HTD. We changed some things including the pulley size and went to 15mm* GT2 for a few years. This year we used 15mm HTD in order to get parts faster and we had no problems. The only reason we don't go GT2 is that pulleys and belts tend to be less available with longer lead times than HTD. For something like a gearbox like this I would absolutely go with the stronger tooth profile.

*(At this point I'm pretty sure that for the end of a driveline 15mm is a lot safer than 9mm for 4" wheels and pulleys in the 24T range, regardless of tooth profile. If the difference in tooth profile is your factor of safety between failure and success, maybe try going a bit wider.)