thanks i have tryed it with a 25 pinion gear is ok with it but. on a track i got told i would need a 19 pinion gear and turn slipper back a bit . thankyou for your help i tryed it .but dms racing said i would need about 19 pinion does anybody know what size pinion people use on a track and i was going to put a fast motor in it as well .thanks people for help me