[mistercrash]

This is what I had.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1.8333333333333333
Other Ratio: 1
Spur Tooth Count: 54
Pinion Tooth Count: 24
Total Voltage: 22.2
Motor KV: 1577
Tire Diameter (inches): 5.65
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.008
Spur/Pinion Ratio: 2.25 : 1
Total Ratio: 13.64423 : 1
Tire Circumference (inches): 17.75 inches (450.85 mm)
Rollout: 1.30:1
Total Motor Speed: 35009.4 RPM
Vehicle Speed: 43.13 mph (69.28 km/h)
Effective KV Value: 1577
KT constant: 0.86 oz-in/A

Now I opened the tranny and took the CD out and put back the stock Traxxas spool. I checked the gears and all bearings and everything is in top shape in there. My wheels are well balanced. I always balance my wheels the best I can. There's no binding anywhere on the drive train, everything spins very freely. The body had holes in the front grill and a big round hole in the windshield. Plenty of air flow there. I was running a pair of Zippy-H 3S 5000 mah 20C. The truck weighs very close to 14 pounds with 3S lipos in it.

While I was working on the truck, I reinstalled the stock XXL Losi wheels and tires so I changed my gearing. Now when I use Brian's top speed estimator, I never factor in tire ballooning. Maybe I should so I recalculated with .25'' tire ballooning this time and this is what I'll be trying.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1.8333333333333333
Other Ratio: 1
Spur Tooth Count: 58
Pinion Tooth Count: 19
Total Voltage: 22.2
Motor KV: 1577
Tire Diameter (inches): 6.75
Tire Ballooning (inches): .25
Motor Current Draw: 0
Motor Coil Resistance: 0.008
Spur/Pinion Ratio: 3.05 : 1
Total Ratio: 18.51147 : 1
Tire Circumference (inches): 22.78 inches (578.52 mm)
Rollout: 1.23:1
Total Motor Speed: 35009.4 RPM
Vehicle Speed: 40.79 mph (65.52 km/h)
Effective KV Value: 1577
KT constant: 0.86 oz-in/A