Does this look safe over all

[notnodak]

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)

[rschoi_75]

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.

[kulangflow]

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.

[notnodak]

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