i have a t4 and i was wondering what kind of gearing i should run with the trinity 10.5bl thanks!

Depends on where your driving and what you want to achieve. The RTR comes stock with an 87 teeth spur and 21 pinion. With the stock 87t spur I would go with 18-21 teeth pinion. With an 84 tooth spur 18-22 tooth pinion. Lower teeth pinions gives more punch and less top speed. Higher pinions give more top end, less punch, and the motor will get hotter. On my local track I run a lower pinion if I'm getting good traction. When the track is dry, rock hard and has poor traction, I run a higher pinion.

i have a t4 and i was wondering what kind of gearing i should run with the trinity 10.5bl thanks!

I have a couple Trinity Duo 10.5 motors I have been using about 9 months now both racing carpet touring cars and dirt offroad (No Ovals). Using Novak GTB SS speed controls and Checkpoint 5400 lipos, I have never come close to lipo voltage cutoff or thermalling. In the touring car with high traction, I ran a 52 -100 (64 pitch) ratio which was the biggest I could get in the car after remachining bulkheads to the max. The temperature for me was about 140 post race. I did not chill the motor or anything extreme like that. Some guys did as they were gearing even higher and/or cranked the timing. Offroad 2wd I ran a 36 - 88 (48 pitch) with no problem. These motors have tons of torque and will handle the biggest pinion your car can likely handle if you need/want to go that fast. A bigger pinion will help with a little with low traction offroad too.

Good luck! -Andy