I am no expert on 1/12, today was my son's first time running it or any onroad for that matter. We were running uncut crc purple stripe tires and because I didn't have much for 64 pitch gears, we played around with 48 pitch. We ended up at 30/65, he qualified 2nd because he got stuck on a tube, but was ables to take the win by a little more than half a lap. Hope that helps some. We also used a reedy 13.5 1s ss motor with the timing turned all the way up.