Brose, Bosch, Shimano, Fazua, Panasonic, Giant e-bike systems… which has more power, which has more battery punch, which is more reliable? Our guide to e-bike motors has the answers. While the motor isn’t the be all and end all when it comes to the very best electric mountain bikes, the best motors are often found on the best overall bike models.

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Bosch Performance Line CX

Best for reliability

• Motor weight: 2.9kg (2.75kg for the Race version)
• Modes: Eco, Tour, eMTB, Turbo
• Power: 600W
• Torque: 85Nm
• Battery: 500Wh, 625Wh, or 750Wh
• Charging: 5.4 hours for 625Wh battery, with standard charger
• Energy density: 625Wh – 178Wh/kg, 750Wh – 170Wh/kg

Bosch’s considerable experience in consumer electronics and motors is obvious in the highly polished Performance Line CX motor. There’s plenty of power, but it’s easy to control and ultra responsive. The modes are well judged, with eMTB giving you copious grunt when you need it, then dialling back the power to maximise range. In Turbo there’s plenty of overrun, which lets you boost over uphill obstacles. Bosch control units were always its weak point, being big and bulky, but the latest integrated top tube System Controller and wireless, Bluetooth Mini Remote are discreet and a joy to use and the smartphone app lets you tune the characteristics of the motor. For less weight, a hair trigger response, and extended two metre overrun, the limited edition Race motor is something special.

Read our full review of the Trek Rail 9 with Bosch Performance Line CX motor

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SRAM Powertrain

Best for wireless tech and auto-shift

• Motor Weight: 2.9kg
• Modes: Range, Rally
• Power: 680W
• Torque: 90Nm
• Battery: 630Wh or 720Wh (250Wh range extender available)
• Charging: N/A
• Energy density: 630Wh – 203Wh/kg, 720Wh – 175Wh/kg

SRAM’s new Powertrain takes the smooth, silent Brose S-Mag motor found in the Specialized Turbo Levo and gives it a twist, adding wireless connectivity and Auto-Shift technology thanks to integration with the latest T-Type AXS transmission. There are only two power modes, but they’re fully customisable, and two battery sizes – a lighter 630Wh unit and a long-range 720Wh option.

Auto Shift hands shifting duties over to the computer, and it works ok in certain situations, less effectively in others. But you can turn it off, and still benefit from the excellent shifting and clean, wireless controls. Range is impressive, even with the smaller battery, and there’s ample power even on the steepest ramps. Only available on certain models from Propain, Nukeproof, GasGas, and Transition currently.

Read our full review of the SRAM Powertrain motor/transmission

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Brose S Mag

Quietest motor

• Motor Weight: 2.9kg
• Modes: Eco, Trail, Turbo
• Power: 565W
• Torque: 90Nm
• Battery: 500Wh or 700Wh
• Charging: 6 hours for 700Wh battery
• Energy density: 700Wh – 179Wh/kg

This is the motor found on Specialized’s Turbo Levo, and while it has suffered from a high failure rate in the past, updates to the latest version seem to have cured the reliability issues. Relatively quiet thanks to its belt drive, there’s plenty of power and a nicely calibrated response that feels completely natural. Specialized’s Mission Control app lets you customise the performance, and the new integrated top tube Mastermind TCU gives you access to more data then you’ll know what to do with, and even lets you plot a route and let the motor adjust the power to make sure you have enough range to get round.

Read our full review of the Specialized Turbo Levo Comp

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Shimano EP801

Best motor for compact dimensions and crank interface

• Motor weight: 2.7kg
• Modes: Eco, Trail, Boost
• Power: 600W
• Torque: 85Nm
• Battery: 504Wh or 630Wh (third party options vary, up to 900Wh)
• Charging: 6 hours for 630Wh battery, with standard charger

Shimano has just updated its flagship EP8 motor, but you’d never know from looking at it. Power has been increased by 80W to 600W, but torque remains unchanged, and the rattle when coasting can also be a problem on some examples, but there’s better sealing and a couple of new accessory connections. EP801 is also compatible with Shimano’s Auto Shift drivetrain if you want to let an algorithm choose your gears. The control unit and display are neat and unobtrusive, but there’s no % display for battery life, so it’s not obvious how much juice you’ve got left. Equally, the range seems to be much better with third party battery options than Shimano’s own BT-8036 unit. We also love the splined crank interface, low weight, compact dimensions, and narrow Q-factor.

Read our first ride review of the Shimano EP801 motor

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Shimano EP6

Cheaper, heavier Shimano unit

• Motor weight: 3kg
• Modes: Eco, Trail, Boost
• Power: NA
• Torque: 85Nm
• Battery: 504Wh or 630Wh
• Charging: 5 hours for 500Wh battery, with fast charger

A cheaper option to the EP801, the EP6 gets the same power and torque but packaged within a heavier casing. It’s still compatible with Auto Shift.

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Yamaha PW-X3

Punchy and effective

• Motor weight: 2.75kg
• Modes: Eco, Basic, Active, Sport, Power
• Power: N/A
• Torque: 85Nm
• Battery: 625Wh, or 750Wh
• Charging: N/A

Yamaha’s latest motor is found on various Haibike models as well as Giant’s range of e-bikes, badged as the Syncdrive Pro and Yamaha’s own range of e-bikes, including the Moro 07. We’ve had long term test bikes from both Giant and Haibike fitted with this motor, and in both instances it has proven trouble-free.

Read our review of the Giant Trance X Advanced E+1 with Yamaha/Giant Syncdrive motor

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Rocky Mountain Dyname 4.0

Best for power and torque

• Motor weight: 3kg
• Modes: Eco, Trail, Turbo
• Power: 700W
• Torque: 108Nm
• Battery: 720Wh
• Charging: 3hrs 55mins for 750Wh battery, with fast charger

Rocky Mountain was making mincemeat of its rivals way back in 2017 with its innovative Dyname motor. Driving the chain off an idler pulley, the motor packs a hefty 108Nm of torque and 700w of peak power. And you can immediately feel those numbers when you ride it – it’s a beast. Another benefit of the design is that it uses a standard BB and crank interface, so it’s serviceable and replaceable. It also allows Rocky Mountain’s designers freedom to put suspension pivots exactly where they want, and keep the geometry identical to their non-assisted counterparts. The latest version has a lighter motor, better sealing, improved calibration, a larger capacity battery and a neat display integrated into the top tube.

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Bosch Performance Line SX

Most powerful lightweight motor

• Motor weight: 2kg
• Modes: Eco, Tour, eMTB, Turbo
• Power: 600W
• Torque: 55Nm
• Battery: 400Wh with optional 250Wh range extender
• Charging: TBC
• Energy density: 400Wh – 200Wh/kg

Bosch has finally entered the ‘lightweight’ sector with the new Performance Line SX system. The new motor looks like a shrunken Performance CX unit with a magnesium casing and two-bolt mount. Weight is a reasonable 2kg – which is not the lightest on the market, but still competitive with the 1.95kg Fazua and Specialized SL 1.2.. It pumps out an impressive 600w peak power, making it on par with most full fat options and way ahead of its lightweight rivals. At 55Nm, peak torque is more in line with expectations, meaning it won’t be able to crawl up near vertical pitches like a full fat. To extract maximum power you need to keep the cranks spinning really fast – over 100rpm – so it’s not a motor for riders who like to grind out a low cadence.

Providing power is a new 400Wh internal battery backed up by an optional 250Wh range extender. This gives it the biggest potential capacity of all the lightweight units. With a battery weight of 2kg, you’re looking at a 4kg system – 3kg lighter than Performance CX – and complete bike weights in the sub-20kg range.

Read our first ride review of the Bosch Performance SX motor

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Fazua Ride 60

Best mid-power motor for overall range

• Motor weight: 1.96kg
• Modes: Breeze, River, Rocket
• Power: 450W
• Torque: 60Nm
• Battery: 430Wh (2.3kg)
• Charging: 3.5 hours for 430Wh battery, with standard charger
• Energy density: 430Wh – 186Wh/kg

Fazua’s evolution of the original Evation system ups the power, torque and range while remaining impressively light and low friction. Now you can tap into 450W of power for up to 12 seconds at a time, while the 60Nm torque is enough to wrangle up steep, technical pitches. The 430Wh battery will do 1,000m of climbing in the most powerful Rocket mode, which is impressive, but the Ring Control remote feels worryingly fragile. Fortunately there’s nothing to actually break, but we’d prefer if it had a more obvious click. Motor reliability is the big question mark with Fazua’s system, as 75% of test bikes we’ve had with the Ride 60 have suffered problems. At least there is now a dedicated Fazua service partner in the UK through Upgrade.

Read our review of the Pivot Shuttle SL with Fazua Ride 60 motor

Specialized SL 1.2

Great all-round package

• Motor weight: 1.95kg
• Modes: Eco, Trail, Turbo
• Power: 320W
• Torque: 50Nm
• Battery: 320Wh (160Wh range extender available)
• Charging: N/A
• Energy density: 320Wh – 178Wh/kg

Specialized’s lightweight motor option has just been upgraded and is now called the SL 1.2. Headline updates are that max power has risen from 240w to 320w and torque has increased from 35Nm to 50Nm. Specialized also claims a reduction in noise thanks to different internal gearing. The battery remains 320Wh, boosted by a 160Wh external range extender, so don’t expect to go as far on a single charge with the updated motor as the old one.

Read our first ride review of the Specialized S-Works Turbo Levo SL with SL 1.2 motor

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TQ HPR50

Lightest, quietest, and most compact mid-power motor

• Motor weight: 1.85kg
• Modes: Eco, Mid, High
• Power: 300W
• Torque: 50Nm
• Battery: 360Wh
• Charging: 3hrs for 360Wh battery
• Energy density: 360Wh – 200Wh/kg

TQ’s HPR50 is the most compact motor on the market thanks to its harmonic design, where the motor runs concentric to the bottom bracket axle. Not only is it hard to see, it’s almost silent in operation, making it utterly stealthy in use. The control unit is also compact and the top tube mounted display gives just enough info in an easy-to-read package. We got 800m of climbing out of the 360Wh battery in High power mode, so it’s reasonably efficient too. The only downside of the small footprint is that it can get very hot.

Read our full review of the Trek Fuel EXe with TQ HPR50 motor

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Forestal/Bafang EonDrive

• Motor weight: 1.95kg
• Modes: Eco, Sport, Race, Nitro
• Power: 400W
• Torque: 60Nm
• Battery: 360Wh
• Charging: 1hr 24mins to 80% for 360Wh battery

This petite Bafang unit has been tuned by Forestal and found on the brand’s range of lightweight e-bikes. In Nitro mode there’s stacks of power and torque, so despite the weight saving package, you can conquer some impressive climbs. There’s also a sophisticated colour touch-screen display embedded in the top tube, and a compact remote on the handlebar. With the stock 360Wh battery and no range extender, we only managed just under 700m of climbing in Nitro mode, so it’s not the most efficient option on the market. There’s also no option to tune the power in each mode, and we’re still waiting for the promised range extender.

Read our review of the Forestal Cyon with Forestal/Bafang Eondrive motor

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E-Bike motor torque and max power at a glance

Full power

• Rocky Mountain Dyname 4.0: 108Nm/700w
• SRAM Powertrain: 90Nm/680w
• Brose Drive S-Mag: 90Nm/565w
• Panasonic GXO: 90Nm
• Bosch Performance Line CX: 85Nm/600w
• Shimano EP801: 85Nm/600w
• Shimano EP8: 85Nm/520w
• Shimano EP801: 85Nm/600w
• Yamaha PW-X2: 80Nm
• Shimano E8000: 70Nm
• Shimano E7000: 60Nm
• Giant SyncDrive N/A

Mid power

• Bosch Performance SX: 55Nm/600w
• Fazua Evation Ride 60: 60Nm/450w
• Forestal/Bafang Eondrive: 60Nm/400w
• Fazua Evation 1.0: 55Nm
• Specialized SL 1.2: 50Nm/320W
• TQ HPR50: 50Nm/300w
• Specialized SL 1.1: 35Nm/240w

Range comparison – Mid power motors

For this range comparison we used the same test circuit, with the same tyres, at the same pressures. The rider was the same and conditions very similar. We used the maximum power mode on all four bikes.

As you can see, the Fazua motor gave the best range by a long way, delivering over 1,000m of elevation in the top Rocket mode before running out of juice. In second place was the old Specialized SL 1.1 motor (with 35Nm torque), that managed 924m of elevation. Third was the Trek Fuel EXe with the TQ motor, chalking up 802m, while the Forestal lagged a long way behind in fourth with 691m.

Since that range test, we’ve also benchmarked the latest Bosch SX motor, and updated Specialized SL1.2, found in the latest Levo SL and Kenevo SL models, along with the TQ and Fazua Ride 60. The Specialized motor delivered just under 10% less range at 850m elevation, while the Bosch SX fitted to the latest Whyte E-Lyte achieved 842m in Turbo mode, despite having 400Wh battery. This was done with four different riders, so not directly comparable.

Rule #1: Don’t buy an e-bike based solely on its motor

Yes, it’s easy to get caught up in the stats and worry about getting left behind in a drag race to the trailhead, but never lose sight of the fact that a motor is only one aspect of what makes a good e-bike. The frame, suspension, geometry, sizing, and components all play a huge part in creating the overall ride quality and handling performance of an e-mtb. So while the motor is important, a great motor won’t make up for poor suspension or geometry.

What happens if my motor stops working?

The stuff of nightmares, but sadly it’s something all e-bike owners will experience at some point. When your motor does stop working, as long as it’s within warranty, it’s just a simple case of contacting the brand or shop that you bought it from, and they will sort it under warranty. If you are out of warranty, then fear not. Most problems can be repaired by one of the UK’s specialist e-bike motor service centres. The cost depends on which motor you have, and how complex the repair, but to give you an idea, a full service is around £300-400.