I'm running 17.5 anf I come off after 8 min main at like 170 deg and my truck moves great down the straight and good bottom end to make jumps after cutting turns tight. I've ran motors this hot for a long time with no problems and I even know a fast guy who wins a lot at my local track who runs almost if not over 200 deg after the main and he pulls everybody on the straight and carry corner speed well to make the jumps well, nobody else would even try to gear as high as he do but you know what he wins hahahahaha