Chain Length Calculator
Chain length is a function of two sprocket sizes and the distance between their centres. Vendor charts hide the third number by assuming it. That assumption holds if your bike is stock and your axle sits where theirs did. This calculator asks you for the measurement instead, and gives you a range across your full axle adjustment rather than one number.
Every published figure we found is reproduced below with the vendor’s name against it. We are not the authority on this. They published the numbers, we attribute them, and we tell you where they stop applying.
The calculator
This calculator runs entirely in your browser and needs JavaScript switched on. The vendor charts, the sources and the explanations below read normally without it.
Why this asks you to measure
Centre distance is the distance from the countershaft sprocket centre to the rear axle centre. It is the one number in the chain length formula that a chart cannot know, and it moves for several ordinary reasons.
An extended swingarm changes it directly, and it is one of the most common modifications on this class of bike. Where the axle sits in its adjustment slot changes it by the full length of that slot, which is typically enough to move the answer by a link or two on its own. A chain tensioner changes the effective wrap, so the chain a tensioned setup needs is not the chain the same geometry needs without one.
A fixed chart cannot see any of that. It was produced on one bike, in one configuration, with the axle in one position, and it is correct for that bike. The moment yours differs — and an axle two thirds of the way back in its slot already differs — the chart is answering a question about someone else’s motorcycle.
Measuring takes a couple of minutes and it costs nothing to be right. Measure twice, fully forward and fully rearward, and feed both figures in. The output is a range because your bike is a range.
Published vendor charts
These charts assume the stock wheel at an assumed axle position. That assumption is not stated on the source pages, but it is the only way a fixed tooth-count-to-link-count table can work at all. Read them as a starting point and check against your own measurement.
| Rear teeth | Published by | ||
|---|---|---|---|
| Woody’s Wheel Works | ecossemx1 | Ebikezilla | |
| 42 | 104 | — | 104 |
| 44 | — | 106 | — |
| 48 | 106 (OEM) | 106 | 106 |
| 52 | 108 | 108 | 108 |
| 54 | 110 | 110 | 110 |
| 56 | 112 | 112 | 112 |
| 58 | 112 | 112 | 112 |
| 60 | 114 | 114 | — |
| 64 | 116 | 116 | — |
| Rear teeth | Published by | |
|---|---|---|
| Woody’s Wheel Works | ecossemx1 | |
| 42 | 106 | — |
| 44 | — | 108 |
| 48 | 108 | 108 |
| 52 | 110 | 110 |
| 54 | 112 | 112 |
| 56 | 114 | 114 |
| 58 | 114 | 114 |
| 60 | 116 | 116 |
| 64 | 118 | 118 |
Sources for the two tables above
- Woody’s Wheel Works, Sur-Ron and Talaria sprocket listing — woodyswheelworks.com/products/sur-ron-talaria-sprocket. Retrieved 2026-08-19.
- ecossemx1, Sur-Ron Light Bee upgraded DID chain listing — ecossemx1.com. Retrieved 2026-08-19.
- Ebikezilla, Rear Sprocket 58T for Sur-Ron LB-X and Segway X260 — ebikezilla.com. Retrieved 2026-08-19.
Worth saying plainly: these three published charts agree at every overlapping tooth count for the stock wheel. There is no vendor dispute to arbitrate here. Where one publishes a figure and another does not, the ones that do publish match. The disagreement this site exists to resolve is not between vendors — it is between any fixed chart and a setup that is not stock.
When the published charts stop working
The charts hold for a stock bike. They come apart in four ordinary situations, and none of them is exotic on a Light Bee class machine.
A non-stock wheel diameter is the most common. Going from a 19 inch rear to an 18 or a 16 changes the wheel, and while wheel diameter does not itself change centre distance, the swap is almost never done on its own. A wider tyre can force dishing the rear wheel away from the chain, which changes chain line without changing centre distance and can change what actually clears. An extended swingarm changes centre distance directly and by a large amount. And a primary chain conversion — belt to 219 chain — changes the countershaft sprocket, which is the N1 term in the length formula.
The vendors say as much themselves. Luna Cycle, on their chain extension kit listing, note that an 18-inch wheel with a 3.5-inch Shinko “may require an extra link and master to be added for tire clearance”.
“may require an extra link and master to be added for tire clearance” Luna Cycle, chain extension kit listing, lunacycle.com, retrieved 2026-08-19
That is the people who sell the parts telling you the fixed chart has a limit. We agree with them, and we have gone one step further by asking you to measure instead of guessing.
What we will not do is fill the gap with invented numbers. This site holds no measured centre distance figures for any aftermarket swingarm, and it will not publish estimates of them. If you have fitted one, the measurement is the only route to an answer, and the calculator above is built to take it.
Before you ride
Check chain tension before riding. Fit the chain, set the axle, and confirm free play at the tightest point of wheel travel before you ride.
Once you have the chain sorted, the other half of the decision is the tooth count itself — choosing a rear sprocket size by terrain covers what each size is actually for, and the gearing calculator will show you what it costs you in top speed.