Inline, Sidewinder and Anglewinder Chassis

Enter the number of teeth on your pinion and crown/spur gears, click Calculate and the gear ratio will be calculated for you. To calculate a new set of gears, click Reset and start over.
The formula is Crown/Spur Gear / Pinion Gear = Gear Ratio.

 

Pancake Motor Chassis

With five gears in the drive train, pancake motors are more challenging to calculate. The idler gear on the gear plate is ignored since, due to having the same number of teeth as the driven cluster gear, it has no effect on the drive train other than reversing the direction of the gears.

Enter the number of teeth for your Cluster, Armature Pinion, Crown and Cluster Pinion gears to find the gear ratios and final drive ratio.

Cluster gear / Armature pinion gear = Armature Ratio
Crown gear / Cluster Pinion = Drive Ratio
Armature Ratio / Drive Ratio = Gear Ratio at the Axle

Final Drive Ratio

The final drive ratio takes the gear ratio and tire size into consideration to generate the final drive ratio.
Copy the "Final Gear Ratio at the axle" from above to the box below, enter the Tire Size, click Calculate and the Final Drive Ratio will be calculated.

Popular Inline, Sidewinder and Anglewinder Gear Ratios

HO

Tyco:
Pro:
Pinion: 7
Crown: 18

HP, 440, 440-X2:
Pinion: 7
Crown: 25

Aurora:
G-Plus
Pinion: 6, 7, 8
Crown: 20

Super G-Plus
Pinion: 7
Crown: 25

Auto World:
Super III
Pinion: 
Crown: 

Lifelike/Rokar:
"M" and "T" Chassis:
Pinion: 7
Crown: 25

1/32

Most RTR 1/32 cars:
Pinion: 9
Crown: 27

1/24

1/24 Drag Racing:
Pinions: 9, 10, 11, 12, 13, 14, 15
Crowns: 46, 50, 52, 54