Why is it rare for an e-bike to have more than one chain-ring?

[linklemming]

Let us clarify one thing:

1. Mid-drive motor e-bikes are typically equipped with a single chain-ring (exceptions exist as Browneye has said);
2. Hub-drive motor e-bikes are often equipped with multiple chain-rings.

My 2018 Bulls Evo 3 Brose Motor Hardtail MTB has a 28/38 double chainring and 11/42 11 speed cassette. While I dont use the smaller chainring much, it does come into play on super steep, technical terrain especially if/when I am riding in the lowest power level. It also allows the chainline to be better at the extremes.

That being said, I could live with just a single chainring. The bike comes with holes in the frame for a dropper post. If I ever install a dropper, I will use a single chainring front.

 

[Stefan Mikes]

While I dont use the smaller chainring much, it does come into play on super steep, technical terrain especially if/when I am riding in the lowest power level.

Er... Chris Smith of the Electric Mountain Bike Network climbed both THE SLAB and THE DAM using a single chain-ring

 

[linklemming]

Er... Chris Smith of the Electric Mountain Bike Network climbed both THE SLAB and THE DAM using a single chain-ring

I doubt they were in the lowest power level, I also think they dont really care about long term reliability.

 

[PDoz]

My 2018 Bulls Evo 3 Brose Motor Hardtail MTB has a 28/38 double chainring and 11/42 11 speed cassette. While I dont use the smaller chainring much, it does come into play on super steep, technical terrain especially if/when I am riding in the lowest power level. It also allows the chainline to be better at the extremes.

That being said, I could live with just a single chainring. The bike comes with holes in the frame for a dropper post. If I ever install a dropper, I will use a single chainring front.

I'm 34 to 11/42 11 sp, 27.5 rear.
I honestly don't miss the 2x front.

For really technical climbs I use the second lowest gear and full assist (360%) - it's a struggle to control wheelspin vs keeping the front at the front....now I should probably be clear here, " really technical climbs" are things I can't walk up, usually short sharp steep climbs / double black diamond descents done in reverse on quiet days when nobody is coming the other way. Not steady climbs like in those videos
Lowest gear is for walk assist only

 

[Johnny]

I have a 2x on my yamaha bike. I like it and prefer it to 1x unless it is a mountain bike.

It has advantages such as wide range of gears and the chain is staying more straight compared to 1x10-12 systems. You can have a cheap 8 speed cassette, wider chains without sacrificing the range.

 

[Stefan Mikes]

I doubt they were in the lowest power level, I also think they dont really care about long term reliability.

Of course it was the Turbo mode.

 

[Stefan Mikes]

For really technical climbs I use the second lowest gear and full assist (360%) - it's a struggle to control wheelspin vs keeping the front at the front....now I should probably be clear here, " really technical climbs" are things I can't walk up, usually short sharp steep climbs / double black diamond descents done in reverse on quiet days when nobody is coming the other way. Not steady climbs like in those videos

Chris Smith fell backwards with his e-bike on a real technical climb in one of the recent videos, badly hurting his finger...

Lowest gear is for walk assist only

Oh. I even didn't think about it, thank you for the hint!

 

[PDoz]

Yeah....scary stuff...dropping the bars on a little finger without gloves or body armour....

 

[pmcdonald]

I have front derauileurs on three ebikes with hub motors. One would think them redundant, but it allows a better cadence choice for changing elevations and wind with a cadence sensor, if you're riding on pedal assist at slower speeds.

If you're bombing along at max assist, or have torque sensing, you probably don't care.

I agree with this. I opted for a mid drive with 20 gears recently, over the usual 5-10.

I use a about 75% of them on my rides. I enjoy travelling through them to find my ideal cadence depending on how much energy I have to throw at the ride. One of the bikes I test rode had 9 gears. I couldn't find my sweet spot at cruising speed - it feel somewhere between two gears.

 

[Stefan Mikes]

One of the bikes I test rode had 9 gears. I couldn't find my sweet spot at cruising speed - it feel somewhere between two gears.

You can always replace some cogs in the cassette.

 

[RabH]

My Giant Road E+1 Pro has 22 gears (50-34 x 11-32) and I use all the gears frequently, at the moment I am mostly using the large chainring because I'm doing shorter rides due to the lockdown but when I do longer rides I use the small chainring to keep my cadence up to save battery power! I don't think I would manage 100 mile rides with a single chainring!

 

[E-Wheels]

I couldn't find my sweet spot at cruising speed - it feel somewhere between two gears.

if you have a 10SP, try a 11-23 cassette, which has 1x tooth increments

 

[indianajo]

P.s. personally I think they are a pain in the you know what. From my perspective, the question I would ask is why on earth would you want to put multiple front chain rings on ANY ebike ? With the extra power from e assist, an Ebike OEM could design it with a larger front chain ring, and do 11 or 12 speeds on the rear hub. I'd prefer the simplicity of a design like that over multiple chain rings any day.

I don't want to change chains twice a year. So I've got 3/32" chain. And I want my lungs ready for covid19, or prevent the stroke I'm due for in 2 years, so I ride unpowered up 15% grades in 32:28 or 32:32. Other places 42:24 or 52:24. The motor is for 25 mph headwinds, which didn't used to happen in September & April before 2018. Besides shifting 3 times out of every stop sign on a 7 speed rear damaged my right thumb joint. I certainly don't want to shift 5 to 7 times off every stop. 8 speed rear 11:32 is entirely enough speeds.
Most ebikers won't ride 1000 miles in the life of the bike, much less in 6 months. Sell them a mid-drive with an 11 speed rear sprocket. Americans are desperate to jump into their coffin.

 

[Al P]

My 21 speed mongoose has three chainrings. Before adding the motor, I used the two largest ones, but never the smallest one. Now I almost never use the center one. In fact, I sometimes feel like I'm peddling too fast in the highest gear, so I'm thinking of replacing the largest chainring with one with an extra tooth. This bike was designed as a hybrid MTB, but I don't climb mountain trails. The sometimes steep paved roads I ride are no problem for the large chainring.

 

[stanmiller]

The new rear cassettes provide 500% or more gear ratio range which is amazing and good enough for most mtn bikers.

I think it's more meaningful to express that spread in gear inches as that captures the chainring as well.

Bicycle Gear Inches Table | BikeCalc

Calculate gear inches given chainring, sprocket, tire and wheel sizes.

www.bikecalc.com

When I converted my Mongoose Envoy to a hub-driven electric, my intention was to replace the three ring crank with a single. After all, my electric Electra Townie is a 1x8 and always seemed reasonable to pedal along. I'm glad I didn't and stuck with the 22x32x42 configuration up front.



I also upgraded the drive train to 3x9 with a MicroShift Advent derailleur. The Advent supports up to a 42T rear cog though I'm currently running a 11x34T cassette.

The Envoy is geared like a truck and pedal friendly even while riding acoustic - which I often do. Out-of-battery, no problem...

The gear inches spread is 100.2 to 17.36 or a nice gallop down to a leisurely walk.

 

[Sierratim]

One of my sons, the engineer with WTB, tells me it's an industry tred to move away from front derailleurs, i.e. use a single chain ring. One of his favorite MTBs, Pivot, only offers this setup. Both of my MTBing sons like the simplicity of the setup and not having to deal with front chain drops, slow shifts, etc. They feel that the 12 speed cassette gives them pretty much the same gearing that was really available on a 3x9 setup after taking into account gears that you couldn't access due to cross chaining, nearly duplicate ratios, etc.

He tells me that several major component manufacturers have stopped development of new front derailleurs due to this trend.

So, apparently this isn't just an ebike thing...

 

[indianajo]

One of my sons, the engineer with WTB, tells me it's an industry tred to move away from front derailleurs, i.e. use a single chain ring. One of his favorite MTBs, Pivot, only offers this setup. Both of my MTBing sons like the simplicity of the setup and not having to deal with front chain drops, slow shifts, etc. They feel that the 12 speed cassette gives them pretty much the same gearing that was really available on a 3x9 setup after taking into account gears that you couldn't access due to cross chaining, nearly duplicate ratios, etc.

Why should be out riding our bikes, when we could be hauling them to the store in our pickup trucks to have them worked on? 1000 miles life of 11/12 speed chain doesn't even cover an entire summer. The whole purpose of lifestyle accessories is to spend money on them.
My SRAM 3 front shifter hits the gear at least 90% of the time. At least some cargo bike manufacturers are building bikes to be ridden a lot of miles.

 

[TForan]

A powerful e-bike doesn't need more than five gears in most circumstances.

 

[pmcdonald]

if you have a 10SP, try a 11-23 cassette, which has 1x tooth increments

Sorry, it was 9 speed, 11 - 36 cassette. In this case the rest of the components weren't as compelling a package as the 20 speed model, plus I'm not a tinkerer.

My reflection on the comments in this thread are if you've got the additional cog(s) up front you're probably using them, and if not you'll get by just fine without. Each to their own. My previous bike sported a geared hub with 24 gears. Now that was overkill. I find I cycle through gears a lot more on the mid drive though.

 

[PDoz]

Just out of interest, is there anyone who has sampled a modern 1x 9-12 speed drivechain and then decided to return to 2 or 3 x ?

Even my wifes 1x8 speed norco scene with a nexus hub has more than enough gear range to cope with any terrain she is likely to ride . I specifically bought this model because she never understood the front / back gear relationships , and also being able to change gears after coming to a stop in top gear seemed helpful.....

My kids accoustic mountain bikes are mostly 1x - they love it compared to the 3x childrens bikes they started out with. Admittedly some of that might be stepping up from vase level components to shifters that cost more than the previous bike was worth!