I'm contemplating about getting an electric assist MTB but as much as I can see all (or at least majority) of e-bikes are equipped with 1x transmission.
Is there a reason why there are no e-bikes with more than 1x drive-train?
asked Dec 24, 2017 at 20:16
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You could fit the motor to the front wheel of a common double/triple?– Criggie ♦Commented Dec 25, 2017 at 1:14
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2Modern 1x give a gear range of up to 500% (10-50 cassette) . Few, if any, riders need more than this, and its a much wider range than was commonly available 10 years ago on 3x setups. Why, with a motor, would you need more.– mattnzCommented Dec 25, 2017 at 2:55
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2@mattnz make that an answer please. I disbelieved you, and you are right.– Criggie ♦Commented Dec 25, 2017 at 5:02
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I'm not looking for an upgrade of my current bike but I was curious why only 1x on e-bikes. If I ever save enough money to buy e-bike, I would use motor only on uphils where I guess 1x is more than enough. My reasoning is that on flats 2x/3x setup could be used while motor is off to save battery.– False IdentityCommented Dec 26, 2017 at 11:04
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Actually, that's not true, Yamaha allows 2x setups. Look at the Haibike range of bikes.– Dmitri NesterukCommented Jun 23, 2018 at 22:32
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1 Answer
Well, there are a couple of reasons most MTB ebikes are 1x models:
Modern motors on ebikes provide enough of a kick to get you up a steep hill as well as enough speed to go 50kmh on flats. Even a basic 750 watt motor is stronger and faster than almost any rider's legs. I’m not sure what more gears would give you except more complexity and weight.
A modern wide-range, mountain derailleur gives you more than enough capacity and given the motor assistance, you don’t need to be at the optimal cadence that closer spacing would give you
Many higher end ebikes have bottom bracket motors such as the Bosch or Yamaha systems, which don't allow for front derailleurs (the Bosch for example has internal gearing - a big advantage of which is that the chainwheel is very small and allows for greater clearance with a lower bottom bracket height)
Many battery packs are located behind or near the seat post. This makes the placement of a front derailleur difficult or impossible.
Some ebikes have throttles which makes the placement of shifters on both sides more complex.
Of course, it's really easy for you to add your own rear hub motor to an existing 3x10 MTB if you really want one. But the cheaper vendors are going 1x to save money and the expensive vendors are using bottom bracket motors which aren't FD compatible.
Case studies:
1) Low-end fat ebike (Sondors fatbike, around US$700-1000, rear hubmotor). The battery compartment takes up the entire main triangle, which means you can't fit a front derailleur without some cutting and sawing. Not having a front derailleur also no doubt saves some money. Note that this is the fat Sondors but he regular Sondors has the same design.
2) High-end Specialized MTB (around US$3000; Bosch mid-drive). The Bosch bottom bracket motor means that a front derailleur is impossible to fit as the motor/bottom bracket has internal gearing.
answered Dec 24, 2017 at 23:21
