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E-MTB motors in a comparison testBosch or Shimano?

Florentin Vesenbeckh

 · 20.12.2020

E-MTB motors in a comparison test: Bosch or Shimano?Photo: Markus Greber
Bosch or Shimano? Who builds the best e-MTB motor?
With the EP8, Shimano raises the bar in terms of weight and size to a new level. But how does the e-bike motor fare in direct comparison with Bosch? We tested both in the lab and in practice.

Bosch, Shimano - and then nothing for a long time. If you look at the selection of e-MTB models, two drives clearly dominate the market. With the introduction of the Generation 4 engines last year, Bosch has cemented its leading position. Shimano's E8000 was considered a discontinued model. Now, after months of anxious waiting, Shimano has also presented its latest e-drive. Can the brand new EP8 hold a candle to the Performance CX?

Update: A current comparison (as of Dec. 2022) of 5 E-MTB motors can be found in the article: FAZUA, TQ, SPECIALIZED & CO - 5 lightweight e-bike motors put to the test

Shimano motor 400 grams lighter than Bosch Performance CX

The most striking new feature is the slimmed-down Shimano drivetrain. The EP8 is ten per cent smaller and also significantly lighter than its predecessor. The comparison to Bosch: The Japanese motor saves over 400 grams and the dimensions are also a whole lot slimmer. The latter is primarily a visual argument, because in terms of installation space and freedom in the design of an E-MTB, both drives hardly restrict the developers. An E-MTB with 430 mm chainstays? It's possible with these two drives. In this discipline, Bosch and Shimano are joint leaders in the field of powerful e-bike motors, with the competition from Brose and Yamaha taking up more space.

The dimensions of the two e-bike motors are not worlds apart. However, when you hold the motors in your hand, the more compact shape of the Shimano EP8 is immediately noticeable. The Shimano is slimmer towards the front/bottom in particular, which can provide more ground clearance off-road, depending on the frame construction. Photo: Georg Grieshaber The dimensions of the two e-bike motors are not worlds apart. However, when you hold the motors in your hand, the more compact shape of the Shimano EP8 is immediately noticeable. The Shimano is slimmer towards the front/bottom in particular, which can provide more ground clearance off-road, depending on the frame construction.

However, the engine's innards are decisive for the drive performance. This also includes the software. Bosch demonstrated the importance of programming shortly before the launch of the EP8. The Swabians have given their Performance CX just got a power boost as if they had deliberately kept this ace up their sleeve. Without changing a single component of the drive, the engine suddenly delivers even more torque and drives even more smoothly. It's hard to believe that the adjustment in the data sheet - 85 instead of 75 Newton metres - was a coincidence so shortly before the EP8 premiere. No matter, it's definitely just right for our duel: two competitors at eye level.

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Shimano or Bosch: Which e-bike motor has the edge in a duel?

Which motor delivers more power? And which one is easier to control? You can conveniently download the complete comparison test of the engine duel as a PDF below the article. The test costs 1.99 euros.

Why not free of charge? Because quality journalism has a price. In return, we guarantee independence and objectivity. This applies in particular to the tests in EMTB. We don't pay for them, but the opposite is the case: we charge for them, namely tens of thousands of euros every year.

The E-MTB motors in the fact check:

The facts about the Shimano EP8: 2.52 kilos (EMTB measurement), 3 speed levels that can be customised via app. Max. Torque on the EMTB test bench: 79 Newton metres. Photo: Markus Greber The facts about the Shimano EP8: 2.52 kilos (EMTB measurement), 3 speed levels that can be customised via app. Max. Torque on the EMTB test bench: 79 Newton metres. The facts about the Bosch Performance CX: 2.96 kilos (EMTB measurement), 4 gears, only customisable with Nyon display. Max. Torque on the EMTB test bench: 79 Newton metres. Photo: Markus Greber The facts about the Bosch Performance CX: 2.96 kilos (EMTB measurement), 4 gears, only customisable with Nyon display. Max. Torque on the EMTB test bench: 79 Newton metres. Sporty, compact and minimalist: Shimano is sticking to this philosophy with the new EP8 display. The advantages are excellent protection against damage, a discreet look and good operability. When it comes to additional functions, Shimano is at a disadvantage. The biggest drawback: the inaccurate battery level display without percentage values. Photo: Markus Greber Sporty, compact and minimalist: Shimano is sticking to this philosophy with the new EP8 display. The advantages are excellent protection against damage, a discreet look and good operability. When it comes to additional functions, Shimano is at a disadvantage. The biggest drawback: the inaccurate battery level display without percentage values. Bosch's Kiox display (left) offers even more functions since the last update, including a Komoot navigation display. However, the Kiox is significantly bulkier than the EP8 version and the ergonomics of the control panel are only moderate. Some manufacturers therefore opt for the somewhat outdated Purion display. Photo: Markus Greber Bosch's Kiox display (left) offers even more functions since the last update, including a Komoot navigation display. However, the Kiox is significantly bulkier than the EP8 version and the ergonomics of the control panel are only moderate. Some manufacturers therefore opt for the somewhat outdated Purion display.

The test: On the trail and in the test lab

For the duel, we tested both motors extensively and in direct comparison. The candidates not only had to prove themselves on the trail, but also on the test bench in the EMTB test lab. Photo: Markus Greber For the duel, we tested both motors extensively and in direct comparison. The candidates not only had to prove themselves on the trail, but also on the test bench in the EMTB test lab.
The duel between the two most popular e-bike motors: Shimano versus Bosch. Photo: Markus GreberThe duel between the two most popular e-bike motors: Shimano versus Bosch.

Downloads:

E-bike motor duel: Bosch versus Shimano (pdf)

Florentin Vesenbeckh

Florentin Vesenbeckh has been on a mountain bike since he was ten years old. Even on his very first tour, he focussed on single trails - and even after more than 30 years in the saddle of an MTB, these are still the quintessence of biking for him. He spent his youth competing in various bike disciplines and later his cycling career was characterised by years as a riding technique coach. Professionally, the experienced test editor now focusses on e-mountainbikes. In recent years, the qualified sports scientist and trained journalist has tested over 300 bikes and more than 40 different motor systems in the laboratory and in practice.

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