Does this look safe over all
 

I've got a stock 3905 E-Maxx with a current set-up of Ammo 36-56-2600, 17t pinion, 68t spur, MM esc and a Turbotronix UBEC
Speed calculator says this and it is pretty good

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.8333333333333334
Other Ratio: 1
Spur Tooth Count: 68
Pinion Tooth Count: 17
Total Voltage: 16.8
Motor KV: 2600
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0.25
Motor Current Draw: 55
Motor coil Ω: 0
Spur/Pinion Ratio: 4 : 1
Total Ratio: 20.87179 : 1
Tire Circumference (inches): 19.63 inches (498.73 mm)
Total Motor Speed: 43680 RPM
Vehicle Speed: 38.91 mph (62.51 km/h)
Effective Speed Rate: 2.32 mph/V (3.72 kmh/V)
Estimated Adjusted Speed: 37 mph (59 km/h) - 5% loss
Effective KV Value: 2600
Motor Torque: 0.15 ft-lbs
Final Torque: 3.11 ft-lbs
Final Power: 924 watts (1.2 HP)


BUT I just ordered a 9xl and have a 20t/22t/24t pinions to use and I'll get a 62t spur. Calculator says this: Is it safe as far as heat and pull on the motor?

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.8333333333333334
Other Ratio: 1
Spur Tooth Count: 62
Pinion Tooth Count: 24
Total Voltage: 16.8
Motor KV: 1853
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0.25
Motor Current Draw: 75
Motor coil Ω: 0.0091
Spur/Pinion Ratio: 2.58 : 1
Total Ratio: 13.4797 : 1
Tire Circumference (inches): 19.63 inches (498.73 mm)
Total Motor Speed: 29865.73 RPM
Vehicle Speed: 41.2 mph (66.18 km/h)
Effective Speed Rate: 2.45 mph/V (3.94 kmh/V)
Estimated Adjusted Speed: 39 mph (63 km/h) - 5% loss
Effective KV Value: 1777.72
Motor Torque: 0.29 ft-lbs
Final Torque: 3.84 ft-lbs
Final Power: 1260 watts (1.7 HP)

I've run a 9XL on 4s geared at 22/66 with an older emaxx and it worked very well. The motor did hit temps of 160+ F, but feigao's run hot anyways. I never had a problem for over a year. Still have the motor in another truck now. The set-up above is close, so I think it would be ok. Maybe start w/ your 20T pinion and go from there.

I just ordered a 24T pinion for my 9XL on my 3905. I'll be running it with the stock spur gear (68T I think) if it will fit. I've ordered 65T and 62T spurs also. I'll run it on 4s and 5s sometimes.

I'll let you know how my temps turn out.

Thanks, I'll wait to hear from you. What gearing would work if I used LSTII wheels/tires? a 17t pinion with 68t spur?