Sprocket & Gear
Ratio Calculator
Pick a front and a rear sprocket and get your final drive ratio.
The drivetrain, live
14T front, 42T rear — the rear wheel turns once for every 3.00 turns of the countershaft.
1 — The setup
One slider for the front sprocket, one for the rear. That’s the whole tool — set the teeth and read the ratio.
How to read the ratio
Final drive ratio = rear teeth ÷ front teeth. A bigger number means shorter gearing — quicker acceleration, engine spinning faster at speed. A smaller number means taller gearing — calmer cruising, more top speed if the engine can pull it.
Ratios around your setup
Nearby combos at a glance, built from the sprockets you picked above.
Good to know
Front teeth hit harder
One tooth on the front is worth roughly 2.5–3 teeth on the rear. That’s why “−1 front” is the classic first mod — cheap, easy to fit, and you feel it everywhere. Rear changes are finer tuning.
Watch your chain length
Bigger total tooth changes can need a longer or shorter chain — about every 4 teeth of total change moves the axle roughly one link’s worth. Check chain slack after any swap, and don’t run a tight chain to make it fit.
Before you order
- 🔢Count your teeth — they’re stamped on the sprocket. Fronts usually show the number on the face; rears on the side.
- ⛓️Worn sprockets eat new chains. Hooked, pointy teeth will chew a fresh chain fast. If the teeth look like shark fins, replace the set.
- 🔧Change chain and sprockets as a set when worn. They wear in together. Mixing old and new shortens the life of both.
- 🏍️Small bikes, big effect. On a 125–250cc Chinese bike or pit bike, one front tooth is a huge change. If in doubt, make small changes.