This is how good Bosch's e-bike motor really is: The Performance CX in an endurance test with Whyte

The Bosch Performance CX is ubiquitous in the e-mountainbike world, but the development approach of the Whyte ELyte Evo RS is unique. How do mainstream and niche harmonise? Does the Bosch system live up to its hype - and how does the motor power affect the service life of the bike? After a year of continuous use, we take stock.

Apart from the muffled rumble of the tyres accompanied by the discreet purring of the freewheel, I don't want to hear anything on the descent. If it rattles, my body automatically switches into emergency mode: My fingers cramp up on the brakes and my musculoskeletal system resists pushing the bike further downhill. The fun of riding? As if blown away. There are plenty of quiet mountain bikes - but unfortunately this does not apply to the e-segment. The full-power motors in particular used to torment me with chronic gear rattling, torpedoing my noise-sensitive "stoke level". This annoying clacking - sometimes so penetrating, as if the gears were rolling through the motor housing like bingo balls in a lottery drum - has so far even prevented me from immersing myself in the world of e-mountainbikes outside of everyday testing at BIKE.

On my endurance test bike, these bushings were so badly worn after almost 700 kilometres that the engine developed noticeable play. - Max Fuchs, BIKE test editor

How it all began: The rattle-free Bosch motor

• Power update for the Bosch Performance CX: 100 Newton metres and 750 watts
• Here you can find all the details about the motor: Bosch Performance CX 2025 - The new Bosch in the big test

But then, at the end of 2024, Bosch presented the fifth generation of its Performance CX motor. A patented freewheel system decouples the inside of the motor from the drivetrain and should finally eliminate rattling noises. So far, this has only been achieved with light motors or some niche products. But now the most popular and widespread e-bike motor of all is supposed to stop making a noise when going downhill? I was intrigued. Is that really true? And more importantly, is the bestseller reliable? To find out, I signed up for my first endurance test with an e-bike for the 2025 season.

Inventory

I opted for the brand new Whyte ELyte Evo RS as the basis. In the bottom bracket area: the Bosch Performance CX. Combined with a permanently installed 400 Wh battery, the unit delivers enough oomph and range for fast after-work laps - and at the same time reduces the weight to a hefty 20.51 kilos. The matching range extender for longer rides is included: 250 watt hours of additional energy for docking. We call these lightweight power bikes a small counter-movement in the battery arms race of modern e-mountainbikes.

Like all our test bikes with a motor, the ELyte Evo RS also had to hold its own in our standardised range test. With the integrated 400-cell battery and the 250 watt-hour range extender, the Whyte covered 1548 metres in altitude at an average speed of 13.6 km/h until power failure. This means that under the same conditions, the candidate climbs minimally slower and slightly less high than a Bosch CX bike paired with a classic 600cc battery (approx. 1600 metres in altitude / 14 km/h).

Here you can find all the technical information about the Whyte Elyte Evo RS, how it rides and why its handling is unrivalled in the e-mountainbike segment.

Lots of wear and tear in the endurance test

Frequent short trips and lots of full throttle - a riding profile that quickly wears out combustion engines turns out to be at least a wear booster on the e-mountainbike after eight months. This is because long tours or relaxed commuting were not on the programme during the test period. Instead, I tirelessly fed the test bike with trail kilometres. Forest tracks in boost mode up to the trail entrance, shredding back down at V-Max - until the battery runs out. True to the motto: maximum downhill action in the shortest possible time. Under these conditions, the ravages of time literally ate their way through the hardware, controls and other add-on parts.

Defects list and tuning parts: what went wrong with the Whyte Elyte Evo RS in the endurance test

Capital damage to the Bosch system

The biggest slip-up was the motor suspension. As is usual with Bosch bikes, the drive hangs on two bolts in the frame, each of which runs through a rubber bush on the non-drive side. On my endurance test bike, these bushings were so badly worn after almost 700 kilometres that the motor developed noticeable play. Research revealed that this was not an isolated case. The bolt/bush combination was unable to sufficiently compensate for the manufacturing tolerances of the different frame manufacturers. Bosch has since reacted, revised the motor hardware and provided appropriate retrofit kits for affected models via specialist dealers.

Play and wear on SX and CX: Bosch comments on tolerance problems

Beyond that, the bike has no weaknesses. All bearings run smoothly, nothing has play or creaks. Wear on the drivetrain is also kept within limits thanks to Sram's robust T-Type technology. The motor itself was also unaffected by the constant firing: It pushes as powerfully as on the first day, responds sensitively and downhill you hear nothing but the rumble of the tyres and the whirring of the freewheel.

Conclusion from Max Fuchs

The handling is outstanding: low weight, perfect centre of gravity - I've never experienced any other e-mountainbike as harmonious. That alone makes the Whyte worth recommending. But carefree riding fun looks different: The drive system proved to be an additional source of errors and a wear booster, and cost me a few nerves during the test.