Granite Modified Granite 3s pinion gear recommendations

[Motodeficient]

Hey everyone! I have a Granite 3s with a Hobbywing 3665D G3 2400KV sensored motor paired with a Hobbywing Max 10 SC G2 140A ESC. I'm running 6" tires instead of the stock 5" tire size. What size pinion gear should I be running in this?

 

[GraniteFox]

18-20t should do the trick for hardpack dirt. If you are running in grass I would stick with the 15-16t. I would still run a decent motor fan and keep an eye on temps.

 

[RCbuzz]

Stock on the 3300kV motor is 15T I believe but your motor is only a 2400kV.

Lets figure this out, if it's a Granite 3S:

TRANSMISSION RATIO: 57T Stock Spur / 15T Stock Pinion = 3.8 (Transmission ratio)
GEAR RATIO: 37T Ring gear / 13T Input gear, drive ratio of: 2.85 (Gear Ratio)
Final Drive Ratio: (3.8 X 2.85) = 10.815

We need your tire circumference which will be 6" X Pi (3.1415) = 18.85

Take the circumference and divide by your final drive ratio. 18.85/10.815 = 1.74

Now we need your max motor RPM, 2400kV @ 3S = 2400 X 11.1Volts = 26,640RPM's Max

26,640 X 1.74 = 46,353 in/min --> convert to MPH = ~44MPH

I am actually thinking the stock 15T pinion is probably fine on your setup...

 

[Motodeficient]

Damn, can't get any more of a scientific answer than that, thanks! I might try 4S out as well soon.

I'm running a Hobbywing heatsink and fan on the motor, I believe it's a 40mm fan

 

[slick2500]

Stock on the 3300kV motor is 15T I believe but your motor is only a 2400kV.

Lets figure this out, if it's a Granite 3S:

TRANSMISSION RATIO: 57T Stock Spur / 15T Stock Pinion = 3.8 (Transmission ratio)
GEAR RATIO: 37T Ring gear / 13T Input gear, drive ratio of: 2.85 (Gear Ratio)
Final Drive Ratio: (3.8 X 2.85) = 10.815

We need your tire circumference which will be 6" X Pi (3.1415) = 18.85

Take the circumference and divide by your final drive ratio. 18.85/10.815 = 1.74

Now we need your max motor RPM, 2400kV @ 3S = 2400 X 11.1Volts = 26,640RPM's Max

26,640 X 1.74 = 46,353 in/min --> convert to MPH = ~44MPH

I am actually thinking the stock 15T pinion is probably fine on your setup...

17-18t will bring it up to around stock speed.

 

[Motodeficient]

I would need a mod .80?

 

[slick2500]

I would need a mod .80?

Either 32p or mod .8