I'm new to running 1/12th scale. I've always run off-road. I just about finished putting together my CRC Gen-X. I'm wondering what pinion would be a good starting point with a stock motor? I'm sure it will cary from track to track.
Most racers have a selection of pinions to adjust for differing conditions. Differing conditions include type of stock motor, how it's tuned, track length and layout, and tire size.
In general, today's 27T stock motors are geared to a rollout (distance the car travels per motor revolution) of 1.75" to 2.00". Once you find the proper gearing for a particular track, you will need to adjust your pinion for tire wear.