How to properly maintain an electric mountain bike

With the growing popularity of E-mountain bikes (e-MTB), we see more and more people using them to hit the trails. In response, almost every major mountain bike manufacturer now offers at least one electric mountain bike.

e-MTBs may make more sense to more people. They lower the mountain biking barrier to entry, making it more accessible to different folks. Now, people with different abilities and fitness levels can ride singletrack because of the growing electric bike market.

Riders new to mountain biking are finding their way into the sport through electric bikes. They are jumping in with both feet, purchasing their first bike, which happens to be an e-MTB. Others who have mountain biked for a long time and perhaps own several bikes are adding an electric mountain bike to their stable. They have seen them out on the trails, have a friend who rides them, or just want to get a few extra laps more than usual.

It’s very likely that your e-MTB is the most expensive bike you've ever bought – the added motor, battery, and controller are high-tech components that significantly increase the price. Whether an electric mountain bike is your first or tenth bike, keeping it in the best running condition is essential. This will mean regular maintenance, most of which you can do at home and some of which you may opt to have your local bike shop do.

The bottom line is that you likely spent a good chunk of change on this new e-bike, and you should do all you can to prolong the bike's life.

First things first

Whether you are buying a new mountain bike, gravel bike, or e-MTB, you should do a few things before you hit the trails. How this process plays out depends on whether you purchase your new bike from your local bike shop or have ordered it online directly from the manufacturer.

Buying directly from the manufacturer will likely save you money over purchasing from a bike shop. However, paying a bit extra at a bike shop gives you the peace of mind that not only has the bike shop professionally built the bike, but they will help with any future problems that may arise.

If you buy directly from the manufacturer, which many do, you can expect a large, heavy box to show up at your door. This is where you should start documenting: take pictures of the box, especially if it has holes or is damaged in any way. Inspect each part of the bike as you unbox it, snapping any pictures of damage you may find. For the most part, bike manufacturers do an excellent job packaging bikes and keeping them protected during transport. However, accidents happen, and bikes get damaged in transit, so be on the lookout as you unpack it.

As you assemble your electric mountain bike, take pictures of the bike’s identification and serial numbers. Depending on their location, it may be easier to take photos while the bike isn’t fully built. These pictures will be helpful later when you register your bike with the manufacturer to ensure it is under warranty. To operate as intended, modern bikes require that each and every bolt is torqued to specification – failure to do so will result in premature wear or damage and an unsafe bike. Most manufacturers provide an easy-to-use torque wrench along with the other tools you may need to assemble and maintain the bike. Torque specification for most bolts is written near or on the bolt itself. Do not assume that bolts are torqued correctly from the factory, and check every single one to be sure.

While you are in paperwork and document mode registering your bike for its manufacturer’s warranty coverage, this is also a great time to head over to Velosurance and see about an insurance policy to cover your new e-MTB. Velosurance will fill in the gaps the manufacturer’s warranty leaves open. The warranty from the manufacturer may feel nice, but if you get into the fine print, you will find that your e-bike’s warranty only covers “manufacturer defects.” So, if you crash while cruising down your favorite trail and crack that brand-new carbon fiber frame, the manufacturer won’t cover the damage because the crack in the frame is your fault, not a “manufacturer defect.” The manufacturer has the ability to reject your claim and leave you fronting the bill.

Not only will Velosurance cover your electric mountain bike if it’s damaged in a crash, but it also offers the optional medical payments coverage that will help with medical bills if you are injured. Nothing is worse than trying to figure out how to buy a new bike while recovering from a big crash. Coverage also includes protection against theft, damage while traveling, gear and equipment damage, and more. They’ll even let you choose which bike shop you want to work with to make repairs.

Washing your e-MTB

Regularly washing your electric mountain bike is one of the most important things you can do for regular maintenance. Dirt and dust have a way of working their way into every nook, cranny, and crevice of your bike. All moving parts, such as the drive train, suspension linkages, and fork and shock hydraulics, are susceptible to dirt infiltration, which will cause premature wear of these components. The type of “washing” you do will depend on the conditions of the trails you are riding and the dirt building up on your bike. A dirty bike is no good, but too much water can also harm your e-MTB too.

Summertime riding usually means a dusty e-bike afterward. Here, you can use a microfiber cloth and waterless bike wash. The waterless bike wash will not only help pull the dust off the bike but also help prevent the dust from scratching the frame or components. Simply spray the waterless bike wash on and wipe it away, paying particular attention not to wipe the dust into the bearings and seals you are trying to keep clean. The areas that you want to especially make sure are dust-free are the suspension stanchions, the dropper seatpost stanchion, headset bearing, bottom bracket, and any suspension linkage bearings.

Be careful with this spray, however, as it is usually not good to have any sort of spray or aerosol come into contact with your brake pads or rotors. This will cause loud, squeaky brakes that eventually stop working. For the most part, companies making a bike-specific wash are making it okay to get on your brakes, however, it is better to be safe than sorry. Double-check the instructions on the bottle, or just keep your brakes covered. Another option would be to spray the bike wash directly on the rag rather than the bike. Simply wiping down a dusty bike works great to quickly clean it without spraying it with a bunch of water. But, your drivetrain will be difficult to “wipe down” and may require a normal wash with water.

If you’ve been riding more wet trails and you have a little more than dust on your e-MTB, it may be time to break out the hose and wash kit, found at your local bike shop. Similar to wiping down your bike, pay special attention to the important areas like bearings, dust seals, and suspension stanchions. When using the water, have the nozzle on a more gentle setting, like “shower,” and stand back a bit. Try your best not to spray the dust seals and bearings with water directly. If you have the nozzle in a gentle setting and have some space, this shouldn’t be too much of a problem. If the water jet is too strong, water can get past seals and into your suspension and bearings. On top of that, you will also be pushing the very dirt you want to remove into those seals and bearings.

Dirt and dust build-up is a leading cause of drivetrain damage and issues. When mixed with chain lube, dirt and dust become a grimy mess that literally eat away at your drivetrain's gears and chain. Unfortunately, water isn’t going to remove this grime so you’ll have to degrease the drivetrain. Again, make sure to cover your brakes, as they definitely will not like the degreaser.

Apply the degreaser directly to your drivetrain and start scrubbing. Pay particular attention to the derailleur and in-between the cogs on the cassette — this is where dirt and grime like to hide. Use a smaller brush to get into these smaller spaces.

A particularly dirty or gunky drivetrain may warrant removing the chain from your bike and maybe even the cassette from the rear wheel, to give them a thorough scrubbing just be sure not to lose the spare link. This isn’t something that needs to be done often and should be looked at as “spring cleaning.” But remember, a clean chain will get dirty if the cassette is dirty, and vice versa.

As far as batteries and electric motors go, your e-bike manufacturer has (hopefully) thought through all of this. These bikes are meant to be ridden in all types of weather conditions, so batteries, charging ports, and motors will have quality gaskets to keep water out. However, similar to bearings and seals, it is best not to spray them with water directly.

Under no circumstances should you use a pressure washer on your bike: most bearing and suspension seals, as well as electronic component gaskets, are not designed to withstand the forces exerted by a pressure washer, so you’re very likely to end up with water inside of the moving parts or electronics.

Regular service for your e-MTB

The suspension on your electric mountain bike has regular service intervals. Service intervals are usually calculated by hours spent riding. This, of course, can be tricky because most mountain bikers track miles rather than hours. Fortunately, different apps can record your rides and give you a total ride time. If your bike has an app, this may be something the app records.

The work that goes into servicing suspension isn’t particularly difficult, and you can find many videos online showing how to do it. However, there are specific tools, parts, and oils you will need to do a suspension service. If you aren’t mechanically inclined or limited on space, it’s highly recommended that you let the experts handle it! Give your local bike shop a call and schedule an appointment.

Most suspension components have a 50 and a 100 hour service intervals. For example, both Fox and SRAM recommend 50 hour lower leg service on the forks, which restores low bump sensitivity, reduces friction and extends bushing lifespan. A standard lower leg maintenance involves tasks such as replacing the bath oil, cleaning or replacing the seals if needed, and installing new foam rings. In the case of air shocks, an air can service includes the replacement of dust wipers and O-rings. The 100 hour service is more involved, usually requiring servicing of the damper and spring. Most dropper posts have a 400 hour service interval that for many modern dropper posts consists of replacing a cartridge, which can be done in roughly 15 minutes using normal tools. Generally accepted service intervals for forks and shocks are shown below, for official recommendations please consult the manufacturer of your specific equipment.

Fork

Shock

It’s easy to forget about suspension maintenance because its performance degrades slowly and even the most discerning rider is unlikely to detect its diminishing performance until it has gotten servere. Skipping on maintenance will result in premature wear of some components and collateral damage to others: while consumable components of your suspension such as dust wipers, seals and O-rings are very cheap, active components such as dampers and stanchions are some of the pricier components on your bike.

Because the added power “takes out the sting” out of mountain biking on rugged terrain where sudden hard efforts are needed to maintain momentum or climb, e-MTB riders tend to shift a lot less, effectively staying in the same gear a lot longer and eventually wearing out the few cogs located towards the middle of the cassette. Depending on the component spec of your bike, a replacement cassette may cost anywhere from $150 to $550 so putting an effort into prolonging its life makes sense. Other than keeping it clean and well-lubricated, the next best thing you can do is to learn to use your gears effectively instead of relying on the motor to do all the hard work. Not only will this prolong the life of the cassette, but also extend the range of your battery and make you faster in the process.

The chain might be the hardest working part of the bike - it’s comprised of numerous small parts, all engineered to withstand forces of pedaling and deflections caused by shifting. With the added power of an electric motor, these forces are amplified as much as 4x so it’s not surprising that chains on e-MTBs do not last as long. The chain tends to stretch with use as the pins, rollers and bushings that hold the links together wear out. As it stretches, the way it fits around the teeth of the cassette becomes less precise and eventually the chain starts wearing out the cassette, which results in sloppy shifting and “slipping” gears. Replacing your chain in a timely manner can greatly prolong the life of the cassette - the general wisdom is that a cassette should last as long as 3 chains if replaced at the right interval. How long a chain lasts greatly depends on the weather conditions it’s used in, how clean you keep it, and how much power is put on it. The best way to detect a worn chain is to use a chain wear indicator, which is an inexpensive gauge that does exactly what its name suggests. A chain that’s stretched 0.75% or more should be replaced.

Just as electric mountain bikes can be hard on chains and cassettes, they can also be tough on brakes, too. Added acceleration and weight from a motor and battery mean extra wear and tear on your e-bike’s brakes, wearing down the brake pads inside the caliper. This equals a loss of stopping power overall. If you ride regularly, check your brake pads every month, replacing them when you notice they are substantially worn. Also, while the pads are removed from the caliper, make sure that the inside of the caliper is free from any dirt and grime. When you should replace brake pads depends on the manufacturer's recommendation—Shimano says when the pad is less than 0.9mm, while SRAM says it is when the pad and plate measure less than 2.5mm combined.

If you are still noticing a loss of braking power but your brake pads aren’t too thin, you may need to resurface your brake pads. Dirt and grime from the trail or the road during transport can get in the brake calipers and cause contamination on the rotors and pads. Luckily, your pads can basically be made new again with drywall sanding screens, steel wool, and isopropyl alcohol. Remove the brake pads from the caliper (also a great time to clean that caliper) and rub them in a figure-8 on the sanding screens. This should remove grime, returning them from dull to shiny. Next, spray some alcohol on the rotors and rub them with the steel wool. This will remove any contaminants on the rotors but will also leave steel wool threads you’ll need to wipe away with a microfiber cloth. Replace the pads and put the wheels back on. You will need to bed in the brakes again whether you are resurfacing the brakes or replacing the pads.

Another bit of maintenance you will want to perform is checking all the frame bearings (if your electric bike is full suspension). This isn’t something you need to do as regularly as a suspension service, but depending on how often you ride, about once a year will do. Unless you’re a skilled mechanic, bearing replacement is not a DIY job. There is a specific tool to remove and press the bearings in—the last thing you want to do is damage your frame trying to pry out a bearing. Make your frame bearing overhaul a winter project when you will be off the trails anyway, and take your bike to a shop to let professionals do it.

And, whether you are doing a suspension service or a frame-bearing service, this is also a great time to think about other components. Are your wheels true? Do your hub bearings need to be serviced? Is your headset bearing creaky? What about the bottom bracket? If the bike is already being worked on, it is the best time to have other components checked and updated.

e-MTB battery maintenance

First, batteries should be clean, while dust isn’t a great conductor, when enough of it builds up between the battery terminals, it can cause a small short that can damage the battery or, worse, cause a fire. Disconnect your electric mountain bike’s battery and wipe it down, removing all dust and dirt before each ride. You can even add a bit of grease to areas where the battery rubs against the frame to keep both from wearing. Use a clean brush to break up and wipe dry dirt and dust away if needed.

If you are not going to ride your e-MTB for a while, avoid leaving the battery fully charged or completely discharged. It is best to keep the charge percentage somewhere in the middle and the battery at room temperature. The battery will slowly lose its charge, even when not used, so you may need to give it a bit of juice occasionally.

Your battery doesn’t like extreme heat or cold. To extend your battery's life, store it inside at room temperature, especially if you aren’t riding for a while. If the weather is extremely cold, charge your battery inside, transport it inside a warm vehicle, and immediately install it before a ride. Under no circumstances should you charge a cold battery, it is a sure way to damage it.

The optimum ambient temperature for charging a lithium battery is 41°F to 113°F (+5°C to +45°C). When charging a lithium battery below 32°F (0°C), a chemical reaction referred to as “lithium plating” occurs, and this reduces the battery life drastically and limits the fast-charging capability. In severe cases, lithium plating forms lithium dendrite, which penetrates the separator and causes internal shorts, and the battery could catch fire.

Lastly, stay up to date with software updates for your e-bike. These updates often help with appropriate pedal-assist power output or proper battery usage, prolonging the battery’s life. All batteries slowly lose their overall charge, but proper care and charging will help your bike’s battery last. A battery that maintains 80% or more of its capacity after a full charging cycle is considered healthy by most manufacturers. If your battery can not sustain such capacity and is still within the warranty period, it is a candidate for warranty replacement.

With the added motor and battery, an e-MTB may seem like a bit extra to maintain. However, with the exception of proper battery charging and storing, the rest of the maintenance on an electric mountain bike is essentially the same as any other bike. Keeping your bike clean and well-maintained will have you spinning wheels and changing gears for years.