Bike Chain Replacement: 7 Steps for E-Bike Owners

If you've got a new chain and don't know where to begin, fear not: replacing your bike chain involves fitting the correct chain, cutting it to the right length, passing it through the gears, and then securing the connection before you ride.

You can do the job at home if you've got the matching tools and can check the finished connection. But buying a chain marked “e-bike” isn't enough. Your rear gears, chain length, and connector still have to match.

These seven steps cover e-bikes with a rear derailleur, the shifting mechanism below the rear gears. Belt-drive bikes, single-speed bikes, and internally geared hubs need different instructions. For an unfamiliar connector or a full-suspension bike that needs sizing from scratch, we'd book a mechanic rather than guess.

1. Check Before Chain Replacement

You shouldn't replace the chain merely because your pedals make a squeaking sound. Clean the dirt off and then check the wear using a chain checker that is appropriate for your chain. Observe both the replacement limit given by the chain manufacturer and the instructions provided with the tool, since one level of wear isn't suitable for all drivetrains.

Cracked plates, damaged rollers, or a failing connection need attention too. Stop riding until you've sorted them out.

Before removing an intact chain, note whether its length was right. With the motor off and the bike safely supported, turn the pedals gently by hand and check the largest and smallest gear combinations allowed by your drivetrain. Stop if the derailleur strains or the chain goes slack. A poorly sized old chain isn't a useful template.

2. Match the Replacement Chain

See how many rear sprockets there are and check the drivetrain model since the term 'seven-speed' refers only to the seven rear gears and not to the pedal-assist settings. It is also important to verify that the new chain's stated compatibility, available length, and the required connector are all correct.

For example, Leoguar lists its Shimano 7–8 Speed Chain for Flippo at 114 links. That's a product specification, not a link count for every Leoguar e-bike. The page doesn't identify the exact connector, so ask support before buying separate joining parts.

Leave the chain and the connector in their original packaging on the bench since you'll need the instructions specific to the model when you're cutting and closing the chain.

 

Get a proper fit first; a more expensive chain won't fix the wrong width or worn rear gears.

3. Prepare Your Bike for Chain Work

Switch off the system, unplug the charger, and take out the battery if your user's manual allows you to do so. You don't want the assist or the throttle to become active when your fingers are close to the chain.

Use a repair stand rated for your bike's weight, with the clamp positioned as the bike and stand makers allow. A kickstand alone won't hold the bike safely while you turn the pedals and pull on tools. If you can't support it securely, take the chain and bike to a shop.

Get your chain tool, the connector's opening and closing tools, a rag, and safety glasses ready. Keep oil and dirty rags away from the brake rotor and pads.

Shift gently onto the smallest rear sprocket before removal. Take a clear drive-side photo of the chain's path through the derailleur. It'll help when both loose ends are hanging down later.

4. Remove the Old Chain

To find the joining link, note that it may have various plates or markings, but don't assume every strangely shaped link opens the same way; use the opening method specified for that connector.

For a link designed to open with chain-link pliers, move it to the lower chain run and release it with the matching tool. If the chain uses a joining pin, use a compatible chain cutter to push out an ordinary rivet away from the previous joint.

Keep the tool's driving pin straight against the rivet. If it slides off or bends, stop and reposition it; don't keep forcing the handle.

Ease the loose chain out of the derailleur and off the chainring. Put it on a rag in one piece if you'll use it for counting. A pin you've pushed out isn't a replacement joining pin.

You generally have no need to take off the hub-motor rear wheel when carrying out this task; just leave both the wiring and the axle fittings in place unless the instructions that come with your bike state otherwise.

5. Size Your New Chain

Take the number of links in the original chain as your starting point, on the condition that the chain has the correct length and the gear ratio has not been changed. When pairing links, align inner ends with inner ends or outer ends with outer ends, and include the connector in the count.

Count the links carefully. Don't stretch a tape measure along the worn chain and cut the new chain to that physical length: wear can make the old one measure longer without adding any links.

Lay the chains next to each other, check the count again, and mark the cut. For a common two-piece quick link that replaces outer plates, the shortened chain needs inner-link ends. Other connections have different requirements. Check yours before pushing out a rivet.

Seat the marked link squarely in the chain tool and drive the rivet out with the tool pin centered. Remove the unwanted section, leaving the ends your connector requires.

Missing the old chain? Changed the cassette or chainring? Use your drivetrain maker's sizing procedure instead. Large rear sprockets and rear suspension can change the required allowance, so don't apply a universal “add two links” rule.

Park Tool's chain-sizing guide shows why those methods differ. If you're unsure where to cut, have a mechanic size it. You can remove another link later; you can't make a too-short chain fit by pulling harder.

6. Route and Join the Chain

Make sure that the new chain has a side that faces outwards. Obey the instructions regarding any lettering, plate shape, or directional markings.

Take the chain and guide it around the rear sprocket and through both pulleys of the derailleur. Make sure the chain follows the small metal tab between the pulley wheels so it passes over the tab rather than rubbing against it. Refer to your photo and the derailleur instructions for comparison. If your bike is fitted with a front derailleur, then pass the chain through the front derailleur cage. After that, route the chain around the front chainring and join the two ends together.

For a compatible two-piece slotted quick link, insert its halves through the chain ends, bring the plates together, and seat both pins fully with the approved closing method. Follow any direction arrow. Other quick links, spring clips, and joining pins have their own fitting steps; don't use this method for all of them.

Use a fresh connector with the new chain. Inspect the joint from both sides. It must sit as the maker shows, without a partly seated pin, twisted plate, or gap. If you can't tell whether it's locked, don't ride it. Ask a mechanic to check.

7. Test Chain Movement and Shifting

Turn off the motor and then, by hand, slowly crank the handle forward and observe the entire chain going through the derailleur. Make sure your fingers stay away from the moving gears, since the chain has to bend around the pulleys without a rigid joint or rubbing against the cage tab.

While going through the lower gears, gently turn the pedals and make sure that the chain remains taut on the smallest sprocket and doesn't pull the derailleur too tight onto the largest sprocket. If you encounter any difficulty, slack, or an unexpected jump, stop. Do not randomly adjust the limit screws in an attempt to get the chain to work properly.

Unless the chain manufacturer tells you otherwise, keep the factory lubricant in place; for future maintenance, refer to our chain-lubrication guide instead of soaking the new chain in additional oil.

When the checks have passed, fit the battery in accordance with the instructions. Ride for a short distance at a gentle speed, leaving traffic behind, beginning by starting without assistance if it is safe to do so and then using low assistance. Keep hard starts and steep ascents for after the bike has shifted smoothly.

If the new chain skips under pressure, stop. Worn rear sprockets can cause that even when the chain fits. A motor shouldn't be used to “break in” a skipping drivetrain.

Bike Chain Replacement FAQ

Is DIY cheaper for one replacement?

It may not be if you're buying all the tools for a single job. Ask a shop for a parts-and-labor quote, then compare it with the chain, fresh connector, cutter, and joining tools you'd need at home.

Can I bring my own chain?

Ask the shop before ordering; some shops fit customer-supplied parts, while others have restrictions. Send the exact chain model and your bike's drivetrain details so they can check the fit first.

Should I buy a cassette too?

Not automatically. A worn chain doesn't prove the rear gears need replacing. If your old chain is badly worn, ask for a drivetrain inspection before you buy parts so you can budget for any worn sprockets as well.

Does DIY replacement affect my warranty?

Before you begin, make sure you have checked the terms of your bike's warranty, particularly in the case where you are replacing the chain since another component has failed. Find out from customer support how damage resulting from an incorrect installation will be treated; do not assume that all do-it-yourself work is covered or that opening the chain will lead to the warranty being canceled.

What if my chain isn't listed?

Do not choose the one that looks the most similar. Instead, send Leoguar support your bike model, serial number, the number of rear sprockets, and clear photos of the markings on the old chain in order to get the right replacement and connector.