Overheating An E-Bike Can Be A Buzz Kill, Literally

With budget brand e-bikes, one of the most common problems is overheating. Here are some practical tips and tricks to keeping your bike cool while you're on the road.
robb dorr
Written by Robb Dorr

Too much load on an e-bike motor can get it hot enough to trigger an error code that usually triggers a fail-safe mode. It’s one of the most common problems people find with budget brands, but most bikes that can experience this issue are hub drive systems.

Therefore, understanding a hub drive’s realistic capabilities will help you decide if one is right for you.

Making The Right E-Bike Choices

As the e-bike market rapidly expands, dealers get a taste of sales momentum they’ve never experienced. Therefore, the more informed you are, the better chance you’ll make the right purchase for your style of riding. Getting most dealers to tell you what they have isn’t right for you is a long shot.

On the one hand, you have the consumer’s responsibility to be honest about where they live or ride their bike. For example, if a heavier rider lives on a steep hill, they may need a different e-bike than a 90-pound 4th grader. Then again, selling e-bikes is a business like any other. Ultimately, the more informed you are, the better your chance of getting the right bike.

Hub drives are found on so many bikes these days and have proven to be successful for most people.

Pointing The Finger At Hub Drives

Just like combustion engines, electric motors struggle to dissipate heat as more load is applied. Load, in the case of electric bikes, comes almost exclusively in the form of hills. Steep hills can be too much effort for the average 250 Watt hub drive to handle without any assistance from the rider. Some bikes have more powerful motors, up to 750 watts in many cases, but they’re mostly used in heavier bikes, which somewhat offsets the gain in power.

Two hundred fifty watts is enough power to comfortably propel a 50-75 pound bike and its rider on flat ground until the battery runs out. Hills are a different story, though, and in extreme cases, hub drives can only handle a couple of minutes before an overheating error can stop you. Most companies use a fail-safe error code to put you in limp mode or cut power until it cools down.

If you bring your bike to the point of an error too many times, you run the risk of wearing out the motor and other components. Usually, the insulation around the copper coils that make up the bulk of an electric motor is the first thing to break down. As more load is applied at lower speeds, other components start to malfunction, and sections of the copper windings may start to char after a while.

As a general rule, the more you can feel resistance on your legs, the less the motor has to work and potentially overheat.

Don’t Expect A Fish To Climb A Tree

Hub drive systems on cheaper e-bikes don’t utilize the advanced technology available. Often, basic electric motor and sensor technology — typically in most e-bikes ranging between $1,000 to $2,000 — doesn’t lend itself to the demands of steep hills.

You can usually look at the rear hub of a bike in that price range and see a Bafang stamp on it. Bafang is a Chinese company that produces a massive amount of electric motors for the majority of hub-drive bikes. They’re more impressive than you may think, and we’ve even heard of Bafang motors with over 30,000 miles on them. So the key factor is how the motor is treated. 

The number of overheated mid-drives is almost unmentionable compared to hub drivesMid-drive e-bikes are well known for holding their own on rides with massive elevation gains, but that doesn’t mean they don’t get really hot at the top of a long climb. However, we’ve heard of only a handful of overheating errors in the past few years with the newer generation motors. In almost every case, it was an extremely long climb on turbo mode letting the motor do all the work and often a heavier rider.

Mid-drive e-mtbs like this Husqvarna with a Shimano EP8 are known for being able to climb until the battery runs out.

Tips For Keeping It Cool

Hub-drive bikes often have a generally overused throttle, particularly on steep hills. It doesn’t take long for error codes to present themselves when used in that way. Spending $2,000 on an e-bike doesn’t make it a motorcycle, so putting more effort into pedaling up hills will prevent errors and add life to the system overall.

Shifting knowledge is one of the most crucial things to know when riding hills. Many people are getting back into riding with the help of e-bikes, and if you’re one of those new riders, you may not be familiar with modern shifters and how they work. But this will change your riding experience for the better.

Being in a gear that allows your legs to spin at a relatively high cadence will give you the best chance of helping the e-bike get up hills. Cycling science tells us that putting more power out at a higher cadence is easy. In other words, try to spin your legs a little faster instead of a little harder. As much as you can, try to feel a bit of resistance on your legs when climbing, and if you get too tired or sweaty, take a break.

As we said, it doesn’t take long for most hub drives to warm on steep hills, but they cool down quickly. A two- to five-minute break is a fair amount of time to let it get back to proper operating temperature. But if you start to get errors on flat ground with minimal load, you may have a separate problem which you should consult a bike shop about.

Hub Drive Considerations

Manufacturers usually don’t tell the whole story regarding the potential for their bikes to overheat. One company we won’t name says it’s possible to overheat your bike in extreme conditions like “the peak of summer heat.” In reality, we hear of this happening to people weekly. Many people figure it out and quickly adapt their riding, while others are left angry that their machine doesn’t do what they thought it would. 

Hub-drive e-bikes are sold in mass quantities, and this article isn’t about throwing shade at them. Truthfully, their benefits outweigh this one weak point, but it’s important to understand that before buying one. All e-bikes, whether mid or hub-drive, come in many styles, qualities, capabilities, and price ranges. Do the research and take your time to decide which bike is best for you.

Need a little extra help finding your perfect e-bike? Check out our guide on choosing an electric bike and assess the wide range of options available in our overview of the best bikes of 2023.

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About Our Editorial Team

robb dorr
Written by Robb Dorr
Robb is a massive cycling enthusiast who has more than 20 years of non-motorized cycling experience. He started eBikes.org to lower the barrier of entry to cycling and reduce the intimidation people can experience when getting into the cycling world.

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