Originally Posted by
D-Rek07
What pinion gear should I use on a b4.1 on an indoor clay track with an 81 tooth spur gear to run in the 17.5 non timing class?
You can use the 81 but I would drop to the 78 or 75 if you can. I would start with a 27 or 28 and work your way up from there but most likely you will end up around 78/31 with a non-timing setup. Always keep tabs on your motor temp.