Originally Posted by Bob Barry

I suggest you grab 33,34,35,36 for pinions. This covers you for different layouts, different temp days, etc.... The difference between 34 and 35 can be minor or it can be huge. There's a lot of variables.

Remember, one misconception is that 17.5 class is a 'stock or beginner' class. In fact it's a spec class. If you want to go fast, you have to get the most of your gear.

Worry about all of that AFTER you are able to run consistently without wrecking. You can have the fastest car on the track and as soon as you blow one turn, you are in last. That's the nature of spec racing. Consistent beats fast every time.

Things you can do to generate more power, but mind you, everything comes at a price. Power = heat = wear :

-Tune your motor so that it is efficient and produces power without generating heat by adjusting the timing. I had someone with a 'motor checker/dyno' help me here. Every motor is different. For example my Viper motors are happy around 45 deg timing, where others may be better around 30 or 50, depending on the motors.

-Gear up so your car is max speed 3/4 down the straight. That is a starting point... tune up or down accordingly, keeping temps down below 150. The lower the better though.

-use higher C rated batteries, 60C+

-charge at a higher amp rate. 8-10 amps