What is gearing?
Final drive ratio is the rear sprocket's tooth count divided by the front sprocket's. A higher ratio (bigger rear or smaller front) means sharper acceleration but lower top speed. A taller ratio favours top speed over drive.
Free tool
Motocross & enduro gearing calculator
Find the right front and rear sprockets for your motocross or enduro bike: final ratio, chain length and speed in every gear. Free, no signup required.
My setup
Pick your motorcycle or enter the values manually.
Bike type
This entry is for the European version. In other markets (US, Canada, Australia…), sprockets or peak-power rpm can differ: check your own bike.
13 or 14 teeth stock on the motocross and enduro bikes in our catalogue.
42 to 52 teeth stock on the motocross and enduro bikes in our catalogue.
Not published by the manufacturer for this bike: speeds are shown at 8,000 rpm. Enter the rpm if you know it.
Distance between the countershaft sprocket axle and the rear wheel axle. For catalogue bikes it is worked out from the stock number of links (about 640 to 710 mm on motocross and enduro bikes).
Width / aspect / rim (e.g. 200/55 R17). ≈ 2138 mm circumference.
Results
Computed live from your setup.
Final drive ratio
3.92
Rear / front. Higher = more acceleration.
Chain links
118
Rounded to the nearest even number of links.
Theoretical speeds
| Gear | at 8,000 rpm |
|---|---|
| Gear 1 | 53 km/h |
| Gear 2 | 65 km/h |
| Gear 3 | 79 km/h |
| Gear 4 | 92 km/h |
| Gear 5 | 110 km/h |
Peak-power rpm not published by the manufacturer for this bike: speeds are calculated at 8,000 rpm. Enter the rpm in the setup to see the speed at that rpm.
Theoretical estimates that do not account for friction losses. Expect ±3-5% against real-world speeds.
Simulate a change
Compare your current setup with a variant.
Enable comparison to see how a sprocket change affects gearing.
Practical tips
Tap a tip to apply it in the comparison.
ChangeMost common tweak, finer steps but more expensive to replace.
Understand
Motorcycle gearing, made simple
Front vs rear: which to change?
- Front sprocket Small toothed wheel on the gearbox output shaft. Swapping it takes 15 minutes and costs little. One tooth less shortens the ratio by roughly 6-8%.
- Rear sprocket Large toothed wheel on the rear wheel. Changing it may require re-tensioning or adjusting chain length. One extra tooth shortens the ratio by 2-3%, perfect for fine-tuning.
- The final ratio Final drive ratio = rear ÷ front. The higher the number, the sharper the acceleration and the lower the top speed.
Chain length calculation
Swapping the front or rear sprocket shifts the chain's resting position. The calculator estimates the chain length in links (rounded to the nearest even number) so you can buy the correct chain without doing the maths yourself.
Go further with Tarmago
Add your bike to your garage and track the wear of your chain and sprocket kit.
Create my free accountMotocross and enduro gearing FAQ
What gearing should I run on a motocross bike?
The stock gearing suits most tracks. Go shorter for a tight or technical track and taller for a fast track where you hit the limiter: one or two teeth at the rear for a small change, one tooth at the front for a big one. The calculator shows the effect on every gear before you buy anything.
Front or rear sprocket: which one to change in motocross and enduro?
On an off-road bike the front sprocket is small (13 or 14 teeth stock on the bikes in our catalogue) and the rear one large (42 to 52 teeth). One tooth less at the front therefore shortens the gearing by about 8%, as much as 3 to 4 more teeth at the rear. Use the front sprocket for big changes and the rear one for fine tuning.
Do I need a new chain when I change the rear sprocket?
Not always: one or two extra teeth often fit with the same chain if the adjuster still has room. Beyond that, the calculator gives the number of links you need. A worn chain quickly wears out a new sprocket, so the whole kit is usually replaced together.
Which chain does a motocross or enduro bike use?
A 520-pitch chain on every motocross and enduro bike in our catalogue, with 112 to 118 links stock depending on the model. The exact number for your bike appears as soon as you select it.
Why are speeds given at 8,000 rpm?
Manufacturers do not publish the peak-power rpm of their motocross and enduro bikes. Rather than invent a figure, the calculator gives the speed at 8,000 rpm in every gear. If you know your bike's rpm, enter it to see the speed at that rpm.
Does the calculator give the real speed?
No, it is a theoretical speed with no wheelspin. Off-road the rear wheel often spins, so the real speed is lower, especially in mud or sand.