Top performance at the push of a button: E-MTBs can conquer extreme uphills and even climb steep mountains. The downside of lots of power and even more torque: normal chain drives wear out in no time at all.
The Nicolai E-MTB with belt drive and Rohloff gears in the video check.
According to experience reports, the entire drivetrain from chainring to cassette and chain can be worn out after just 500 kilometres if the drivetrain is running under nasty conditions and high loads. The maintenance effort explodes, as do the running costs.
Belt drive on E-MTBs: The durable alternative to derailleur gears?
The Belt drive could be a solution to the wear problem. So far rather unusual on e-MTBs, it should score points with low maintenance requirements and a long service life. Largest Advantage: The belt does not require lubrication and therefore attracts less dirt.
In addition, the belt does not stretch even when worn. Only the teeth are worn down, and the belt can also break at some point. However, the durability should be around three times longer than with a chain drive.
The Disadvantage: The belt drive in combination with a mid-motor only works with a gear hub in the rear wheel. Although this is also very durable, it is heavy, expensive and does not shift under load. Many manufacturers are therefore sceptical as to whether the belt drive is even suitable for use on E-MTBs.
How does an E-MTB with a belt drive ride? Is it possible to climb steep climbs despite interrupting the pull when shifting gears? How well do belts and geared hubs perform off-road? And can they be a real alternative to the chain drive? We were able to ride belt and chain drive in direct comparison.
Gear hub on E-MTB: New opportunity thanks to motor power?
E-MTBs in particular could be a new opportunity for the gear hub. Thanks to the motor power of classic e-MTBs, the problem of the necessary interruption in traction when shifting gears could fade into the background. Especially if the hub and motor communicate with each other, as is the case with Rohloff's electronic E14. Specifically, the entire shifting process should be completed in just 180 milliseconds.
When the hub receives the shift command from the shift lever, it also communicates this to the motor. At the dead centre of the crank, when the rider is not applying any force to the drivetrain anyway, the motor takes the load off the drivetrain for a fraction of a second and the next gear is engaged. If this also works in practice, you would no longer have to actively take the load off the pedal as with the mechanical Rohloff, but could pedal through almost without interrupting the shift.
The drive belt itself is even better on paper. As it requires no lubrication, it is predestined for off-road use. Maintenance is limited to occasional cleaning of the drive components with a hose and brush.
Thanks to a guide groove, modern belts can hardly slip off the pulleys. A type of deflection pulley - the belt tensioner - compensates for the elongation of the rear triangle during compression and makes the belt suitable for full suspension. An additional small guide pulley prevents the belt from falling off the rear pulley.
Defects and belt drive: Remove rear wheel with belt
And in the event of defects, how can the rear wheel with belt drive be removed? The belt insert does not stand in the way of quick maintenance in between. Once the belt tensioner is locked in place, the belt can simply be lifted off the pulleys and the rear wheel can be removed - for example to repair a flat tyre.
If the belt breaks on the road, it cannot be mended, but a multi-tool and a little bit of tinkering skill are enough to fit a new belt on many bikes in a good ten minutes, even on the trail. The biggest difficulty is that the belt must not be kinked during transport.
Unfortunately, this supposedly carefree technology still comes at a price. Full-suspension e-MTBs with drive belts are currently only available from a few brands such as Nicolai, Mitech and Riese & Müller. However, if the performance is also good on the trail, more affordable models from more manufacturers would be desirable.
You can download the complete test "Chain vs. belt drive" from EMTB 1/2022 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.
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Adrian Kaether
Editor
