[lincpimp]

Ok Sike, I have ordered the cooling fan for my redcat, I will do the same if I go with the dual outrunner hb ls.

Here is the math from briang's speed calc with the 4120/14 on 6s:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 1
Pinion Tooth Count: 1
Total Voltage: 22.2
Motor KV: 660
Tire Diameter (inches): 4
Tire Ballooning (inches): 0
Total Ratio: 3.30769 : 1
Tire Circumference (inches): 12.57 inches (319.19mm)
Total Motor Speed: 14652 RPM
Vehicle Speed: 52.71 MPH (84.68km/h)


and with 10s:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 1
Pinion Tooth Count: 1
Total Voltage: 37
Motor KV: 660
Tire Diameter (inches): 4
Tire Ballooning (inches): 0
Total Ratio: 3.30769 : 1
Tire Circumference (inches): 12.57 inches (319.19mm)
Total Motor Speed: 24420 RPM
Vehicle Speed: 87.86 MPH (141.13km/h)


Just wondering if you think the motors can hold up to 25k rpm? I am sure that the rest of the drivetrain can.