(Some) EMTB weaknesses and possible solutions.

[Penttithefinn]

Most EMTB's are using standard drivetrains which is their weakness, the motors mainly being the strength.

Weakness: Chain wear, and breakages. Specifically inner plates and pins. Cassette wear, bending, and chain ring wear. Battery capacity. Motor waterproofing???

Strength: Battery capacity, Motor Torque, multiple output modes.

Drivetrain: For most of us a 52t cog is overkill, and with output 4 modes, it begs the question if we need 12 speeds in most circumstances.

Possible solution: So.... would 8 speeds and a 11- 40ish cassette be more useful/acceptable given that the potential increase in inner plate width and therefore strength/wear resistance be of interest.
Whilst the chain will weigh more, and be stronger, the cassette should be stronger and lighter, and possibly with a larger chainring, better durability for the whole drivetrain.

Motor/Battery: Battery capacity will increase, weight will lessen, and waterproofing will/has improved, and more personal input to modes will be available.

I welcome your views

 

[Sidepod]

Having read a lot of stuff on here it seems to me that the average rider prefers Turbo F”off mode and weights North of 90kg. That’s a lot of load on a motor/chain etc.

8 speed is oft discussed here, the down side being wide ratios.

I’m not sure why you feel current battery life is a strength? Most batteries are only good for half a day of serious riding.

It’s beginning to seem like all threads merge into the same topic.

 

[Penttithefinn]

Having read a lot of stuff on here it seems to me that the average rider prefers Turbo F”off mode and weights North of 90kg. That’s a lot of load on a motor/chain etc.

8 speed is oft discussed here, the down side being wide ratios.

I’m not sure why you feel current battery life is a strength? Most batteries are only good for half a day of serious riding.

It’s beginning to seem like all threads merge into the same topic.

I started by thinking about the engineering side of EMTB's, rather than how people ride them, and there is no doubt that the current drivetrains are inadequate to cope with the torque that can be delivered. So from the point of making a chain which would cope and be a reasonable price, and came up with 8 speed, then asked what is the maximum cog size that "most" people need. I agree range is a limitation, hence I put it as a strength and a weakness. 8 speed would only have wide steps if you want a 50t cog, for me 40 would be fine, but that is why I asked for other views, and yes many topics merging..................

 

[Gutch]

Sram EX1 ebike derailleur and cog was out in 2017.

 

[Gutch]

Sram EX1 ebike derailleur and cog was out in 2017.

8spd

 

[steve_sordy]

We can try to design a bike from an intellectual standpoint, but unless we design and build our own, whether we like it or not the market will decide. Features will be introduced and sold as benefits, but after a while the market will decide and the unsuccessful features fade away and the others will be retrained if not universally loved. Darwin's law applies to consumer products just as much as it does to animal life, except that the life cycle is much faster. The rate of evolution for mtb bikes has been enormously rapid. But many things have survived; chains and derailleurs, spoked wheels, rubber tyres..... New things have burst onto the market and been enthusiastically retained and further developed (or shunned); droppers, 1x, alloy frames, carbon frames, wider tyres, wider bars, hydraulic brakes, tubeless.....

And now the Homo Sapiens to the previous Homo Neanderthalensis - ebikes to the previous bikes (no "e")!

Homo Sapiens has its own Darwinian evolution (as do ebikes). Both species had much in common and were retained because it gave an evolutionary advantage; 4 limbs, walking upright, a powerful brain, speech, family groups, hunter/gathering, gender specialities....... MTB and emtb also have much in common and will develop their commonality in parallel. But emtbs will have further developments still to make. Motors, batteries, software.... all will progress by steady innovation that will be subjected to the market and found better or be found still wanting. An example is the number of speeds. Who has 5-8 any more?, 9 is no longer common. The market is chewing on 10-12, but with strong support for a retro 8-speed (for understandable reasons). The market will decide. Weaknesses and strengths will be exposed, niche areas will proclaim "the answer", and if the niche demand is large enough the solution will stay on the market as aftermarket components, rather than being withdrawn from sale by everyone.

@Penttithefinn I doubt that you will have to wait too long to see what emerges. You or I may not like it, but the market will have spoken. The market is of course all of us collectively.

 

[Gary]

Most EMTB's are using standard drivetrains which is their weakness

No it isn't.
Normal drivetrain components are plenty strong/durable enough. The average EMTB rider cannot output elite cyclist levels of power even with a motor..
Most damaged and broken chains are from poor shifting under load.
The fact that you think a 40t sprocket is small tells me you're probably not an elite level cyclist. A closer ratio cassette and better shifting technique would do more towards a "possible solution" to the "issues" you describe than a wide range 8 speed cassette.

 

[Gutch]

It’s insane.

 

[Eddy Current]

Bolts that get loose happens in many ebikes, loctite is the answer by now.

Real ” e-brakes” is maybe the only e-thing I think can be improved and appealing and I’m not mean guide RE and that standar bike stuff labeled e-

 

[Lucky Pete]

Besides correct useage of current designs, the answer to drivetrain issues is an intergrated transmission. Wonder how far we are away from that being widely adopted....

 

[Penttithefinn]

No it isn't.
Normal drivetrain components are plenty strong/durable enough. The average EMTB rider cannot output elite cyclist levels of power even with a motor..
Most damaged and broken chains are from poor shifting under load.
The fact that you think a 40t sprocket is small tells me you're probably not an elite level cyclist. A closer ratio cassette and better shifting technique would do more towards a "possible solution" to the "issues" you describe than a wide range 8 speed cassette.

You are right, I am far far away from being an elite athlete at 63, with arthritis in both knees having had a (complete) ruptured patella tendon just over 3 years ago. But in your opinion, is the only reason people get through chains, cassettes and chain rings so quickly down to poor maintenance and poor shifting and little to do with design? Lastly you are mistaken if you think I meant that a 40t is small, all I was suggesting was that for many, it would be adequate for most of us, up most hills, and was asking if others thought the same.

 

[Gary]

is the only reason people get through chains, cassettes and chain rings so quickly down to poor maintenance and poor shifting and little to do with design?

No. Not ONLY. But almost certainly MAINLY
with the advancement of 10 then 11 then 12 speed drivetrains outer chain plates and cassette sprockets had to slim down. So YES. there's less material there. But there's still sufficient to get thousands of miles of trouble free use using them with an Ebike if you.

1. look after, inspect and maintain your components
2. regularly clean and properly lube your drivetrain
3. pay attention to where you are and what's ahead and shift gear with care and good timing rather than dumping gearshifts under load

Shifting on ANY derailleur gearing system bike is more efficient when the chain is not under high load/tension. On an Ebike in order to ensure you aren't shifting under high load due to motor over run you actually have to pre-empt each gear shift and ease off allowing the motor to reduce it's assistance.

Lastly you are mistaken if you think I meant that a 40t is small, all I was suggesting was that for many, it would be adequate for most of us, up most hills, and was asking if others thought the same.

Yes. I agree. SRAM and Shimano's latest mtb drivetrains are the most advanced shifting out there BUT using a very wide ratio cassette by it's very nature puts tremendous strain on chains and sprockets in comparison to closer ratio cassettes. and an older 11-28 mid range 10 speed cassette shifts far more smoothly than a modern £300 12 speed 10-52 does. I'm not suggesting everyone run an 11-28 but like you've said with a motor to help us out most of us if able bodied and reasonably fit really should not need to even be looking at super wide ratio 12 speed cassettes.

 

[Gary]

Besides correct useage of current designs, the answer to drivetrain issues is an intergrated transmission. Wonder how far we are away from that being widely adopted....

Not really. Don't think there are no issues with integrated transmission. Especially on an electric mountainbike.

 

[Sidepod]

What e-specific problems are you referring to?
I assume we’re talking about a Rohloff here?

 

[Mikerb]

We can try to design a bike from an intellectual standpoint, but unless we design and build our own, whether we like it or not the market will decide. Features will be introduced and sold as benefits, but after a while the market will decide and the unsuccessful features fade away and the others will be retrained if not universally loved. Darwin's law applies to consumer products just as much as it does to animal life, except that the life cycle is much faster. The rate of evolution for mtb bikes has been enormously rapid. But many things have survived; chains and derailleurs, spoked wheels, rubber tyres..... New things have burst onto the market and been enthusiastically retained and further developed (or shunned); droppers, 1x, alloy frames, carbon frames, wider tyres, wider bars, hydraulic brakes, tubeless.....

And now the Homo Sapiens to the previous Homo Neanderthalensis - ebikes to the previous bikes (no "e")!

Homo Sapiens has its own Darwinian evolution (as do ebikes). Both species had much in common and were retained because it gave an evolutionary advantage; 4 limbs, walking upright, a powerful brain, speech, family groups, hunter/gathering, gender specialities....... MTB and emtb also have much in common and will develop their commonality in parallel. But emtbs will have further developments still to make. Motors, batteries, software.... all will progress by steady innovation that will be subjected to the market and found better or be found still wanting. An example is the number of speeds. Who has 5-8 any more?, 9 is no longer common. The market is chewing on 10-12, but with strong support for a retro 8-speed (for understandable reasons). The market will decide. Weaknesses and strengths will be exposed, niche areas will proclaim "the answer", and if the niche demand is large enough the solution will stay on the market as aftermarket components, rather than being withdrawn from sale by everyone.

@Penttithefinn I doubt that you will have to wait too long to see what emerges. You or I may not like it, but the market will have spoken. The market is of course all of us collectively.

There are lots of markets that are not consumer led, instead being technology led.............and the EMTB market is definitely technology led. Whenever you see brands being interviewed you hear product managers/designers purporting to know what the customer base most want next in terms of development. As far as EMTB is concerned their perception is that the biggest requirement is more range. The most recent development has been almost universal change to 12 speed and electronic operation of gear change and dropper post operation, bigger heavier batteries and/or supplementary batteries.....who asked for those? I am pretty sure if a full market study was undertaken the consumer wish list would be rather different. Unfortunately bike brands can only really influence frame design and are slave to the components industries for virtually everything else on a bike, and most of them have very little focus on EMTB which is a very small niche of their overall market.
Could these be the main customer needs?.........
Better value for money
Better warranties
Reduced wear rate on components
Better reliability

If a brand came out with any or all of the above statements as its USPs I would then believe the market is driving the R and D of bike brands!!

 

[Penttithefinn]

What e-specific problems are you referring to?
I assume we’re talking about a Rohloff here?

No, I was talking about standard drivetrains, but with the cost of drivetrains going up and the "supposed" wear and failure problems, Rohloff hubs are becoming far more attractive in my opinion.

 

[Sidepod]

No, I was talking about standard drivetrains, but with the cost of drivetrains going up and the "supposed" wear and failure problems, Rohloff hubs are becoming far more attractive in my opinion.

My question was to Gary.

 

[Rosemount]

Most EMTB's are using standard drivetrains which is their weakness, the motors mainly being the strength.

Weakness: Chain wear, and breakages. Specifically inner plates and pins. Cassette wear, bending, and chain ring wear. Battery capacity. Motor waterproofing???

Strength: Battery capacity, Motor Torque, multiple output modes.

Drivetrain: For most of us a 52t cog is overkill, and with output 4 modes, it begs the question if we need 12 speeds in most circumstances.

Possible solution: So.... would 8 speeds and a 11- 40ish cassette be more useful/acceptable given that the potential increase in inner plate width and therefore strength/wear resistance be of interest.
Whilst the chain will weigh more, and be stronger, the cassette should be stronger and lighter, and possibly with a larger chainring, better durability for the whole drivetrain.

Motor/Battery: Battery capacity will increase, weight will lessen, and waterproofing will/has improved, and more personal input to modes will be available.

I welcome your views

It`s the pins not the plates that wear .
Pin wear causes elongation and misalignment they are what then wears out the cassette particularly the smallest sprockets .

Speaking of ,its time for a new NX cassette and chain on my bike .
Worn out the 2nd chain . Started jumping in the highest gear on the week end .

 

[Gary]

What e-specific problems are you referring to?
I assume we’re talking about a Rohloff here?

No. I'm not just talking about Rohloff. I'm talking about ALL internal gearing systems. Not just internal hub gearing systems.
A motor will obviously increase wear and maintenance intervals whatever drivetrain/gearing system is used.
Plus any viable durable internal gearing system adds significant weight. If that weight is all at the rear hub the bike also tends to handle terribly.

 

[matt_thebeard]

some motorcycles occasionally use direct drive ie a sealed drive shaft direct to hub with the gearing then being in the motor, using current materials this is much too heavy for cycle use , currently , but is maintainance free ..

 

[Sidepod]

It’s a shame the motor designs are limited by pedal cadence requirements. If they weren’t then we could do away with trannies all together and just have a motor that pulls from zero and revs to the moon, like a e-car motor.

 

[Sidepod]

Almost relevant.

 

[Penttithefinn]

It`s the pins not the plates that wear .
Pin wear causes elongation and misalignment they are what then wears out the cassette particularly the smallest sprockets .

Speaking of ,its time for a new NX cassette and chain on my bike .
Worn out the 2nd chain . Started jumping in the highest gear on the week end .

Bicycle chain wear (elongation) | BikeGremlin Sorry but it is the inner plates and pins that wear, and although its not mentioned the rollers will also wear.

 

[Zimmerframe]

If they weren’t then we could do away with trannies all together and just have a motor that pulls from zero and revs to the moon, like a e-car motor.

Sadly, it's not as simple as that though. You have motor torque and wheel torque :

Should e bikes have gearboxes?

Here's an overview on gearboxes: https://www.singletracks.com/mtb-gear/internal-gearbox-advantages-drawbacks-and-future-possibilities-for-apocalypse-ready-mountain-bikes/ The primary reason gearboxes haven't seen widespread use on regular bikes is because of the added weight and the efficiency...

www.emtbforums.com

or the cadence thread :

Cadence

Been emtb'ing for over 3 years now and never even thought about cadence until today! Seem to remember a youtube video saying cadence should be between 80-100 so I had a quick 12 mile road ride today with cadence on the display rather than speed. Ok keeping 80 wasn't too bad but hitting 100 and...

www.emtbforums.com

 

[steve_sordy]

............Bicycle chain wear (elongation) | BikeGremlin ..............

That is a good article on wear in a chain transmission.

 

[Gary]

It’s a shame the motor designs are limited by pedal cadence requirements. If they weren’t then we could do away with trannies all together and just have a motor that pulls from zero and revs to the moon, like a e-car motor.

Er... What?
Who'd be controlling the revs and how?
For me anything other than torque and cadence controlling assistance just wouldn't be cycling.

Personally I do find the fact that pretty much every mid drive Emtb motor tapers off its assistance above 100rpm but I'm a bit of a anomaly in that I can happily spin at far far higher than that for long periods and hit 200rpm+ peak pretty much anytime I like on a normal bike so long as its in a low enough gear not to make the power output (torque) required ridiculous.

 

[Sidepod]

Er... What?
Who'd be controlling the revs and how?
For me anything other than torque and cadence controlling assistance just wouldn't be cycling.

Personally I do find the fact that pretty much every mid drive Emtb motor tapers off its assistance above 100rpm but I'm a bit of a anomaly in that I can happily spin at far far higher than that for long periods and hit 200rpm+ peak pretty much anytime I like on a normal bike so long as its in a low enough gear not to make the power output (torque) required ridiculous.

As I said, it’s a shame we are restricted to a controlled cadence.

 

[Gary]

Yeah. I was looking for a decent explanation

 

[steve_sordy]

There are lots of markets that are not consumer led, instead being technology led.............and the EMTB market is definitely technology led. Whenever you see brands being interviewed you hear product managers/designers purporting to know what the customer base most want next in terms of development. As far as EMTB is concerned their perception is that the biggest requirement is more range. The most recent development has been almost universal change to 12 speed and electronic operation of gear change and dropper post operation, bigger heavier batteries and/or supplementary batteries.....who asked for those? I am pretty sure if a full market study was undertaken the consumer wish list would be rather different. Unfortunately bike brands can only really influence frame design and are slave to the components industries for virtually everything else on a bike, and most of them have very little focus on EMTB which is a very small niche of their overall market.
Could these be the main customer needs?.........
Better value for money

Better warranties​

Reduced wear rate on components
Better reliability

If a brand came out with any or all of the above statements as its USPs I would then believe the market is driving the R and D of bike brands!!

I agree that the marketeers have different viewpoints in different industries, but in the end it is the customer that makes the buying decision. It make take a few years while the early acceptors pile in and find out whether the performance meets the hype. (Flexible stems, combined brake & shifter levers, so many different BB designs....) Then the feedback starts; gossip at the bike shop, MTB Magazine reviews etc. Before too long, the next set of buying decisions are made... to buy something else! Or the fanfare begins "it's great, best thing since sliced bread!" Everyone piles in; consumers to buy, manufacturers to copy. (1x, droppers, forward geometry, wider bars...)

I agree that the technology keeps advancing, hence your "technology led" proposal. It is a constant pressure to be new, better, lighter and stronger that drives the bike companies. But if they fail to convince the market, then the product dies.

You suggest eminently sensible consumer needs for a bike:

Better value for money​

Better warranties​

Reduced wear rate on components​

Better reliability​

Who wouldn't want those?

But that guy at TREK (Gary Fisher?) said "strong, light, cheap - pick two!" Improve any of the latter three in your list (it could be argued the the last two are the same) and you impact the first one. Yes improving the bottom three may make the bike last longer and hence improve the value for money, but at the cost of putting up the price. How many riders keep a bike for years and years? I know some do because I've met them. I've met dozens of really old road bikers with steel-framed bikes they bought 50 years ago. But I doubt that the rest of the bike is that old. The longest I have kept a bike is about ten years, but that was one really cheap rigid 2x5 hybrid that I bought for getting fit. It was used 2-3 times per week when the weather was nice and it was never hammered. It was the first bike I had owned since I was a child. Once I discovered MTB, I never had a bike for longer than three years and mostly only two years. So why would I pay extra money for a bike that will last for a decade with an associated warranty? What I want is the latest tech, but only as long as it works!

The "e" factor has added a whole new angle to bikes and the perception of those four consumer needs above. Motors, batteries, display, wiring harness, and the software are all new items for the pedal bike fraternity and they are taking some getting used to. They are no longer relatively cheap items, easy to swap out in case of failure outside warranty. If they fail, the bike might be an expensive write off. Maybe the industry needs to think differently about ebikes? But as long as the market keeps buying a new one every 2-3 years they will have no motivation to do so.

 

[Gary]

It was Keith Bontrager.
And he talks a lot of shit.