Workbench tool

Gearing calculator

Change a sprocket, see what it costs. Top speed and wheel torque move in opposite directions, and this shows you exactly how far. Works on any chain-drive bike, not just the ones we sell parts for.

Top speed now 0mph baseline
Top speed after 0mph 0%
Wheel torque 0% 0%
Total reduction 0:1 0%
Top speed0 mph
Pull off the bottom100%

Move the slider to compare.

Mechanical ceiling only. Real top speed lands lower once you add rider weight, tire pressure, terrain, battery sag, and wind. The difference between the two numbers is the useful part, not the numbers themselves.
Every size at once

The whole range, from your setup

Rear Top speed vs now Wheel torque Reads as

Recalculates from your inputs above. The highlighted row is the sprocket you have now.

Bigger rear sprocket

More pull off the bottom, lower top speed, and usually a cooler motor on climbs because it can spin faster for the same ground speed.

Smaller rear sprocket

Higher ceiling, softer launch, and more motor heat at low speed. Only worth it if you actually spend time at the top of the range.

One tooth at the front

Moves the ratio about as much as four at the rear. If you are chasing a small change, the front sprocket is the finer adjustment.

Do not forget the chain A bigger rear sprocket wraps more chain than the stock one. Running a stretched chain on a new sprocket wears the new teeth into the shape of the old ones within a few rides. Replace both together.
Questions

About the numbers

Why is my real top speed lower than this
This is the mechanical ceiling: what the drivetrain allows if nothing else got in the way. Rider weight, tire pressure, terrain, wind, and battery voltage sag all take a cut. Use the difference between two sprockets rather than either number on its own.
Where do I find my primary reduction
It is in the manufacturer's spec sheet, and it is fixed unless you have rebuilt the drive. If you cannot find it, leave the default in place. Primary reduction affects both numbers equally, so the percentage comparison between sprockets stays correct even if that figure is off.
Does a bigger sprocket hurt my range
Not directly. Gearing does not change efficiency much on its own. What changes is behavior: with more pull available, most riders use more throttle more often, and range drops for that reason.
Which sprocket fits my bike
Check the fitment database. Some models need a specific carrier, and a sprocket that fits a Light Bee X does not necessarily fit an Ultra Bee. If your model is not listed, email hello@motorhabit.com and we will check it.

The theory behind this

Why the trade is one for one, what a swap costs in heat, clearance, and chain wear, and which sprocket suits which riding.

Read the guide

Check the fit first

Every sprocket we sell, mapped to the bikes it has been tested on, with adapters named where they are needed.

Open the database

More guides and videos

Install guides, teardowns, and setup numbers for the bikes we cover. Filter by what you ride.

Browse the Workbench