E-bike maintenance: battery, brakes and motor

An e-bike is, first of all, a bike. It has brakes, a chain, wheels and gears like any other, and most problems come from those parts, not from the motor. What changes is that it is heavier, it is usually ridden faster and it puts more force through the chain. That means some parts wear sooner, and there is one new and expensive part to look after: the battery.

The battery: charging

E-bike batteries are lithium ion. They do not need elaborate rituals, but a few habits help:

• Use the original charger, or one the brand lists as compatible. Any charger with the same plug is not the same thing.
• You do not need to run it flat before charging. Lithium batteries do not have the “memory effect” of older types. Charging often does them no harm.
• Avoid leaving it at 0 % for long. If it runs completely flat, charge it as soon as you can.
• Charge it somewhere dry, at room temperature, where you can see it. Do not charge it straight after a ride on a hot Madrid summer day while it is still warm: let it cool first.
• Do not charge it in direct sun or next to a heater, and do not cover it while charging.
• If it has been out in the rain, dry the outside before you plug in the charger.

The battery: storage

This is where most batteries are damaged, especially in winter and summer.

• No extreme heat or cold. A storage room that turns into an oven in August or a freezing terrace in January is the wrong place. A dry spot at indoor temperature is ideal. If the bike sleeps somewhere cold, take the battery inside.
• If you will not ride for weeks, do not store it empty or at 100 %. Most manufacturers recommend storing at around half charge and checking it now and then so it never runs completely flat. Check your brand’s manual, as each gives its own range.
• Do not leave it on the charger for weeks on end.

Never do this with the battery

• Do not open it. Inside there are lithium cells and control electronics. Opening it is dangerous and voids the warranty.
• Do not use it after a hard knock, or if it is swollen, deformed, smells odd or gets unusually hot. Disconnect it, put it somewhere with nothing flammable around and contact the dealer.
• Do not buy unwarranted cell “repairs” or unbranded batteries to save money. If the battery fails, the safe route is the brand or its service centre.

Brakes wear faster

An e-bike with its battery is considerably heavier than a regular bike, and it is usually ridden faster. When you brake, all of that is energy the pads have to absorb. That is why they wear sooner.

What to check yourself:

• Lever feel. The brake should bite firmly well before the lever touches the bar. If it comes closer every week, or a hydraulic brake feels spongy, get it checked.
• Noise. A metallic scraping sound under braking can mean the pad is worn down to its metal backing. Stop riding like that: you are damaging the disc.
• Pad thickness. With disc brakes, look into the caliper with a torch. If there is very little material left, replace the pads.

Many e-bikes have hydraulic disc brakes. Replacing pads is doable with some practice, but bleeding the system or changing the fluid is best left to a workshop.

Chain, cassette and chainring: more force, more wear

The motor adds its power to yours, and all of it goes through the chain. An e-bike chain usually stretches sooner than one on a normal bike, and if it is not replaced in time it takes the cassette and chainring with it.

• Clean and lube it regularly, more often if it rains.
• Measure wear. A chain checker is cheap and takes seconds. Replacing the chain on time costs far less than replacing chain, cassette and chainring together.
• Ease off a little when you shift. With the motor pushing, shifting under full load is hard on the drivetrain. Some systems cut assistance for a moment when you shift, but not all.

Wheels and tyres

• Pressure. With the extra weight, an underinflated tyre punctures more easily and deforms. Check it often, within the range printed on the tyre.
• Tyres. There are tyres designed for e-bikes, with tougher construction. When you replace tyres, ask about them.
• Spokes. A wheel with loose spokes goes out of true sooner under the weight. If the wheel wobbles or you hear pinging, have it looked at.

The motor and electronics: a job for the dealer

The motor, display and sensors are closed systems specific to each manufacturer. It is worth being clear here:

• Diagnostics and firmware updates are done with the brand’s own software, which usually only its dealers and authorised service centres have.
• If an error code appears on the display, note it down or take a photo. Look it up in the manual and, if switching off and on again does not clear it, take the bike to the dealer.
• Do not open the motor. As with the battery, it voids the warranty.
• Do not fit speed limit removal kits. In the EU, pedal assist bikes stop assisting at 25 km/h. Tampering with that means the bike is no longer legally a bicycle, and it voids the warranty too.

What you can do yourself: keep the battery contacts clean and dry, check that cables are not pinched or rubbing, and make sure the speed sensor and its magnet (if your bike has one on the wheel) are in place. A magnet that has moved can throw errors or make the assistance behave strangely.

Cleaning

• No pressure washers. Not on the motor, not on the battery, not on the bearings. Use a bucket, a sponge and a cloth.
• Remove the battery before a thorough clean, if your model allows it, and protect the contacts.
• Dry it well and lube the chain afterwards.

A simple routine

Every week or every few rides: tyre pressure, brake feel, clean and lubed chain.

Every month: pad and chain wear, bolts tight, battery contacts clean.

Once or twice a year: a full workshop service covering brakes, drivetrain, wheels and headset. And, if the brand recommends it, a dealer visit for a check of the electrical system.

When to see a workshop

Brakes that no longer bite like they used to, a stretched chain, gears that skip or a wheel out of true are normal workshop jobs, and on an e-bike they are better not left for later because of the weight and speed. Anything to do with the motor, battery or software belongs with the brand’s dealer. If you are not sure what is wrong, on madridbikes.com you tell us what is happening, mention that it is an e-bike and which brand, and we assign a workshop in your area, in any of Madrid’s 21 districts.