I just installed the low ratio pulley set in my T1R and found to get the same final drive ratio I had with the old 2.125 pulleys I needed a 20T pinion. The only problem is that the belts rubbed on the motor. I put on a 21T pinion which helped but the rear belt is still rubbing. Should I just gear up some more? I'm running stock on a small techinical carpet track. Any help would be apperciated. BTW here is a pic of my car.