Gearbox Calculator

Gearbox Calculator

When building or rebuilding a gearbox, updaing your gear ratios, or changing out your speedometer sometimes you need to update some things. Using the Classic Mini DIY Gear Calculator below, you can determine the correct gearing for your for your new engine build and find the right speedo gear to use as well.

145/80r10
3.444:1 18/62 ( Most Mini's and post '84 Metro's )
6/17 - 10" Mini / 3.44 diff
Standard 1:1 (29 tooth)
2.583
1.644
1.25
1

Maximum RPM

6000
6500
7000
7500
8000
8500
9000
Results

Speedo Information

Speedometer
TPM
Result
100mph Smiths1440

Under 11%

Gearing Information

Gear
Ratio
Max Speed (mph)
12.58342mph

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Please note the above figures are approximate values. Before purchasing parts and building your engine we recommend doublechecking your calculations multiple times using more than one source. The mathematical equations used in this tool can be found here: Equation Source Code

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SUPPORT THE SITE

Classic Mini DIY is completely free resource supported by our viewers. If you are interested in helping to keep the channel alive, consider supporting on Patreon.

Membership comes with tons of free perks and benefits!

Contribute Today

Classic Mini DIY by Cole Gentry .

Classic Mini DIY toolbox is a passion project aligned with the Classic Mini DIY youtube channel. This is a completely free resource built to keep the Classic Mini technical knowledgebase alive for years to come. Regularly updated and crowd sourced data made to help Classic Mini owners all over the world.

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