When it comes to eBikes, it’s easy to get caught up in specs like power, torque, and weight. But in my view, the real sign of a good eBike is that it’s equipped with a serviceable, repairable eBike motor – one you can maintain and rely on for years to come.
Some motors are easy for an eBike repair centre to service, while others are completely proprietary and can only be worked on by the manufacturer. Some brands supply service centres with a full range of replacement parts, enabling repairs well beyond the warranty period – but many do not.
In this article, we’ll explore why many eBike motors trade repairability for performance, the main reasons they fail, and the six motor brands that give you the best chance of long-term reliability.
Let’s get into it!
Why eBike Motors Trade Repairability for Performance
Most major eBike motor manufacturers rely heavily on proprietary components. Bearings, sensors, electronics, and even basic mechanical parts are often custom-designed, preventing independent motor service centres from sourcing replacements.
One reason brands keep their systems proprietary is to tightly control the motor hardware, sensors, battery, and software as a fully integrated package. Torque sensing, power delivery, thermal management, and overall efficiency are easier to optimise when each component is engineered to function as part of a matched system. This level of integration is a big part of why some eBike setups feel exceptionally smooth and polished on the trail.
But there’s also an undeniable business incentive. Proprietary components and software lock customers into a brand ecosystem, limiting competition from third-party suppliers and pushing revenue toward motor replacements rather than repairs.
That said, a handful of brands do work with independent eBike motor service centres to share expertise and a suite of spare parts, and I’ll highlight them later in this article. There’s even one brand that has all the components available to service, repair, and replace yourself!
Why eBike Motors Fail in the Real World
The vast majority of eBike motor failures are usually mechanical, not electronic. Water and dirt ingress into bearings and internal components is the typical cause.
You might wonder why sealing an eBike motor is so challenging, given that effective motor sealing is well-established in other industries. The reason usually comes down to motor efficiency and battery range. Truly robust sealing adds friction and drag, and faced with that trade-off, manufacturers often prioritise range figures over maximum water resistance.
There’s also a market pressure problem. Heavier, more durable motors with better sealing are harder to sell in a segment obsessed with weight, power and range. As brands chase lighter and more powerful designs, long-term durability is often pushed further down the priority list.
Choosing a Motor That Won’t Leave You Stranded
With so many motors showing questionable reliability, it’s wise to buy your eBike from a shop that has a strong relationship with the motor brand. That way, if something goes wrong, any warranty claim can be processed as quickly and smoothly as possible.
Once the warranty runs out, repair costs can rise quickly. That’s why it’s important to avoid motors that can’t be easily serviced in your country.
I’d also suggest choosing a motor with a proven reliability track record. You can see my list of the three most reliable eBike motor brands HERE.
The Most Serviceable & Repairable eBike Motors
Bafang
Bafang motors are also among the most serviceable and rebuildable. Most eBike motor service centres can work on them, and virtually every spare part is available on the aftermarket. They’re also particularly DIY-friendly, with numerous YouTube tutorials showing full teardowns and component replacements, and many open-source configuration tools that you can tinker with.
According to available data, Bafang motors rank among the most reliable. In a survey of 800 riders, they reported one of the lowest motor replacement rates – around 30% below the average.
The most commonly reported issue is increased motor noise or roughness, usually caused by the externally mounted crankshaft bearings failing due to water ingress. Other minor bearings require occasional replacement, while the gear assemblies and teeth typically last a long time, only needing grease very occasionally.
It’s worth noting that Bafang motors aren’t as technologically advanced as others, with a noisier operation and some software inconsistencies.
Parts available: motor controllers, gears, gaskets, freewheels, cabling, stators – basically everything
Bosch
Bosch is the most common eBike motor brand, and fortunately, it ranks highly for reliability, serviceability and repairability.
Most Bosch motors are fitted with high-quality, well-sealed bearings that, if kept dry, can exceed 80,000 km without issues. However, like all eBike motors, these bearings are not fully waterproof, so water can eventually enter the motor if you are not careful.
A water-resistant upgrade kit is available that addresses both water ingress and crankshaft play, protecting the PCB and other internal components. The kit includes a bronze bush on the crankshaft to reduce oscillation and improve sealing, a rotary shaft seal to block water, and a double-sealed left-hand crankshaft bearing. When reassembled, service centres can add extra waterproof grease between the bearings and motor covers to further prevent water and grit from entering.
Bosch motors can sometimes experience software errors, most commonly error code 500 (which has 89 different types). The UK’s eBike Motor Centre collaborated with electronics engineers to resolve code 500 errors, achieving a 90% success rate, meaning full motor replacements are now often unnecessary.
Parts available: complete service kits, water-resistant upgrade kits, bearings, and sprag bearings.
Yamaha & Giant
Yamaha motors (and Giant bikes that use Yamaha-built drive units) rank among the most reliable eBike motors, and they are also highly serviceable. Most eBike motor service centres can perform repairs on them.
Over time, bearings and internal components wear or corrode, and factory grease can dry out. Regular clean-outs and re-lubrication are recommended. The grease on the freewheel pawls can also become sticky, which may prevent proper engagement with the ratchet and potentially damage the freewheel mechanism and steel drive gear.
If a Yamaha motor displays fault codes 34, 64, or any torque sensor errors, this usually indicates a PCB failure. Fortunately, replacement PCBs are available on the aftermarket, so the motor does not need to be discarded.
It’s worth noting that Giant restricts motor swaps: you cannot replace a Giant motor with a Yamaha unit. Giant batteries and controllers are designed to communicate exclusively with Giant motors, and without one of these components, the system will not function.
Parts available: motor covers, printed circuit boards (PCBs), bearings, drive gears, gear assemblies.
Mahle
The Mahle 1.1 and 1.2 motors, better known as the Specialized SL motors, are used on bikes like the Specialized Creo, Levo SL, and Kenevo SL. While reliability data on these motors is limited, they can be serviced at independent eBike motor centres.
Mahle motors are generally regarded as high-quality, with better-than-average sealing. Water ingress and corrosion are less of a concern compared to most motors; the most common issue is the torque sensor sprag (clutch bearing), which can cause intermittent drive loss or slipping and may require servicing or replacement.
The main crankshaft and casing bearings can be affected by water or dust ingress under harsh conditions. These bearings are replaceable, but they are custom-sized and only available from eBike motor service centres that work with Mahle.
Parts available: bearings, o-rings, seals.
Brose (QORE)
Brose (who recently rebranded to QORE) appears to be among the least reliable eBike motors, especially in off-road eMTB use. In one poll of 800 riders, over 30% of Brose users reported needing a motor replacement.
The good news is that QORE motors are highly serviceable, and QORE now supports independent repair centres with factory parts. As Pete Collard from the eBike Motor Centre notes, “there’s nothing on this motor we can’t fix”, making them surprisingly good for long-term ownership.
The most common failure on a Brose is water ingress, which can damage bearings, electronics, and internal components. The internal drive belt is also prone to snapping. Fortunately, aftermarket upgrade kits are now available, significantly boosting both the waterproofing and reliability.
While standard Brose motors come with a single water sealing layer, upgraded versions feature five. X-ring seals and a lip rotary shaft seal help block water from reaching the motor, protecting the crankshaft needle roller bearing. Additional upgrades include sealing the ECU cover screws, applying waterproof grease between the outer bearings and motor covers, and treating the electric plugs to prevent corrosion and water entry. Stronger OEM belts and uprated sprag bearings are also included in the kits.
Brose motors typically require drive belt replacement after around 10,000 miles (16,000 km), while the rest of the motor generally only needs attention if a failure occurs.
Parts available: water-resistant upgrade kits, stronger belts, crankshafts, sprag bearings, gear sensors, and plugs.
How You Can Help With eBike Motor Reliability
Some simple steps can help make any eBike motor more reliable:
- Use batteries that are hidden inside the frame for protection from crashes and weather.
- Wash your bike upright, not on its side.
- Store your bike upright, in a dry area.
- If you transport your bike behind a vehicle, ensure the motor is covered if the roads are wet.
- Do not direct a water hose at the motor, especially the crankshaft area.
- Never pressure wash your bike.
- Do not ford any water deeper than the bottom of the motor.
- Pedal at a higher cadence (RPM).
- Store your battery indoors overnight (protected from weather/temperature).
Summary
When it comes to eBike motors, there should be far less focus on peak torque numbers or shaving a few hundred grams, and far more attention on long-term serviceability and repairability.
I’d strongly encourage choosing a bike with a motor brand that actively supports independent repair, offers a wide range of replacement components, and has a proven track record for reliability. Brands like Bafang, Bosch, and Yamaha/Giant clearly stand out here.
By selecting an eBike motor that can be serviced and repaired, you’re not only protecting your investment and saving money, but also extending the usable life of your bike and helping reduce unnecessary electronic waste.
