Ask the mechanic: electric bike maintenance and care explained

Electric bike maintenance - using the bike properly can save money

"When it comes to the most common e-bike problem we see in the workshop you can break it down into issues that are the result of first-time users or riders and thereafter it's issues with the bikes themselves," Cobb began. "For instance, if someone's new to cycling and they've got an e-bike as their first bike, they may not use the gears much and will instead simply rely on the torque of the motor to get the drive they want. This means that we'll see a heavily worn single sprocket on the cassette [the gear cluster at the rear wheel] and then the whole cassette has to be changed and that means a new chain too. It all starts to add up, but it's easily avoidable if people have been shown how and when to use the gears," Cobb explained.

However, it is not just user error that creates a lot of work for Cobb and his colleagues. While he appreciates working on clean bikes and is happy that people want to clean their bikes, he cautions about the way they do it. While e-bike motors are waterproof and can easily withstand being ridden in the rain or washed by hand, the trend for using pressure washers is a red flag, as Cobb explained. "The drivetrains on e-bikes can be susceptible to water damage. By that, I don't mean from riding through deep puddles, not that I'd recommend that, but more from people using pressure washers to clean their bikes.

"They are so powerful that water gets forced past the seals and into the motors and even the controllers and displays. Once it's in there it sits there and starts to corrode the internal connections."

Due to the nature of these parts, they are not designed to be easily stripped and repaired and complete replacement is often the only solution when something goes wrong due to water ingress, which can be very expensive. That said, some bike brands now claim to offer bike friendly pressure washers.

It is also worth noting that the electrical components of an electric bike are not the only pieces that can be damaged by the over-enthusiastic use of a pressure washer; the bearing in the wheels and the headset can also have the grease forced out of them when sprayed with a pressure washer, leaving them to slowly rust and, in the worst-case scenario, seize up.

Fortunately, Cobb and his colleagues are always happy to advise customers on how to undertake simple maintenance to avoid expensive repair bills. He was also keen to point out that this kind of advice is only available in person and is not something you get when you buy a bargain e-bike online.

Electric bike maintenance: battery care

One piece of advice that Cobb and his colleagues always hand out to e-bike buyers is around battery care, as a faulty battery can be extremely expensive to replace, especially so if it is a high-capacity option.

"We get lots of calls from people each Spring when people decide to start riding again as the weather is improving and they've gotten their electric bike out of the shed or from the back of the garage where it has been stored all winter and the battery will be completely dead.

"They may not have touched the bike for six months. They put it away. They leave it in a cold uninsulated shed. And if the battery's not completely dead when they get the bike out, they may well have done some damage to the cells, which could mean a reduced capacity. It doesn't have to be like this as all they need to do is charge the battery before they put the bike away for the winter and then check the charge level periodically and charge it up as and when it needs it even if they're not planning on using the bike for a while.

"It is unfortunate but a lot of people, when they buy their first e-bike, don't think of the battery as a consumable part. I don't think people are aware that things like batteries eventually are going to wear out. Like your phone, it's got a certain number of charge cycles, and capacity reduces naturally over time. And then at some point in time, you will have to replace it. But if you look after it, keeping it charged when you're not using the bike, that will prolong its life."

The consumable parts on an e-bike are the same as those on a regular bike but, as Cobb explained, they tend to wear more quickly because of the increased power of the motor assistance. "If you look at mid-drive electric bikes with the powers going through the chain to the rear sprockets you're going to wear out elements of the drive train so I would suggest people check those slightly more frequently.

"You might save some money on servicing costs if you catch the wear early and just replace the chain. If you leave it too long and the gears will start to slip, then the whole drivetrain will need replacing. If you're at all unsure about how worn a part is take the bike to your local dealer and ask them to take a look. The cost of regular servicing can save a lot in the long-term as it will identify problems before they become catastrophic."

Little and often: keep a care schedule

Regular servicing with e-bikes also has the advantage that it allows the dealer to ensure the motor's firmware is up to date so that the motor is as efficient as possible. It also allows them to run any necessary diagnostics to check for any potentially hidden problems. "Manufacturers are constantly ironing out software issues," Cobb explained. "So, if there's the latest kind of firmware available, you absolutely want it on the bike, because it's been updated for a reason."

Cobb continued with the benefits of taking an e-bike to be serviced by a reputable dealer. "It's good to ensure everything is as it should be, even small simple things like making sure the contacts for the battery are clean. It's about getting issues early before they become serious. Batteries are some of the most expensive components that you're going to find on an electric bike and so, if you can get the bike checked over by an experienced technician, even if no work needs to be done, you've got peace of mind that there aren't any expensive issues brewing."

Cobb then outlined an occasional problem he's seen when bikes have been brought in for repair after someone has tried to do a little electric bike maintenance at home. "We've seen this a few times when people think that they've got an issue with their bike and they're trying to sort it out themselves, they'll put all sorts of weird substances and lubricants on connections on battery terminals. I don't know what they're using. But it's best to leave those areas clean and dry.

"I always tell people not to start taking things apart and adding their own solutions. The battery connections are an area that can potentially cause problems. For instance, on some bikes, the battery sits on a rack at the back and if the owner damages the rack, they might just try taping it up as a quick fix but I'd advise replacing the rack. In the short term it might seem expensive, but in the longer term it will stop any play between the pins that could cause wear on the battery terminals. Once you get wear there that means a new battery which is hundreds of pounds rather than a few pounds for a new rack."

The next piece of advice Cobb has for e-bike owners is to check their bike's tyre. "Make sure your tyres are at the right pressure because if they underinflated the motor is going to have to work harder and that'll affect the battery's range."

Cobb's final words of advice are: "If you're getting an electric bike for commuting, which a lot of people do, and which they're great for, or taking the kids in a cargo bike, or just cutting out those short car-centric journeys, then yes you'll be spending less money than a car, far less money, but you will still have to spend money on it. Be assured that it is going to be cheaper to do that in the long run. Don't just buy an electric bike and run it into the ground, because it's always going to be more expensive to replace the bike than to spend a bit upfront and keep it feeling fresh."