Gearing
 

I was wondering how you know that you have the right gear on your car besides just looking at your lap times. i have a lrp x-12 and dont want to ruin it because i don't know where it should be.

Temp it after a couple of minutes and then again after 4 if it comes off cold you could add teeth till you get the speed you want. It also depends alot on the speedo you are using it with and the track too. Do you have long straights or mainly twisty and tight sections.

Depending on the speedo, you most likely want to run the -4 dot insert (take motor timing away), especially if you run timing advance/boost/turbo in the ESC. The X-12s are very tolerant of heat (they seem to like to run close to 200 degrees). Ask some racers at your local track what gearing they are running to get a ballpark rollout/FDR/gearing. Then check your temps, and adjust accordingly.

What class are you running and what motor? 1/12 scale, TC? 17.5? 1s or 2s LiPo? What ESC?

im running 1/10th rubber TC. i have a 17.5t motor and a lrp ai brushless reverse esc with a 2s lipo.

Not being familiar with that ESC, here is what I was running with a Tekin with V2.03 firmware

17.5 V2.03
LRP X-12 -4 dot insert
Gearing 35/110 5.34 FDR
Timing Boost 45
Turbo 10
Sensored checked
Turbo Delay 0.0
Turbo Ramp 3.0
Start RPM 2721
End RPM 10001

Motor would come off after 6 minutes at 195 degrees. Very fast. If that ESC doesn't have timing boost, etc, you'll have to gear up (lower FDR - either bigger pinion or smaller spur).

what pitch is your car