Ebike eating chains

[backcountry00]

I have a 2020 Trek Rail 9.8 XT, great bike but Its now destroyed 2 chains in less than 150 miles.
Gears shift nicely so don’t think there is an alignment issue.
First chain snapped when I applied too much power whilst changing gear in higher torque mode, LBS replaced original Shimano chain with a SRAM, and I just killed the new one when I changed gear pedalling up a hill. I’d gone from a high gear to low and from a standstill.

I get that there is more force on an ebike, and perhaps you have to be a little more careful when you change gear depending on power setting and terrain etc, but surely 2 chains in 150 miles isn’t right?
Has anyone changed their chain to something stronger? I’m running a 12 speed.
Cheers

 

[Levo-Lon]

Good practice is learning to back off the leg power when changing up.
A second is all you need. Think of it like a clutch gear change

Full monty power and an up change is severe on a normal drivetrain let alone one putting 70-90 Nm torque into it as well.

I changed my chain yesterday .75 wear 900 miles on a levo

 

[iXi]

I never put any power through the pedals when changing gears. Never snapped a chain.

 

[Mikerb]

For a turbo climb I select a low gear in advance even if that means it is too low to start with. In general I back off any push on the cranks for a seclnd to change gear. I use KMC hollow link chains on a Levo. Current chain has done 650 miles...all trail no road....and is still below 0.75. I lube every ride.....first wet lube then dry lube this time of year.

 

[backcountry00]

Thanks all, looks like I need to adapt how I ride. Coming from an acoustic, I’ve never really considered shifting under load and just rode the bike. The ebike has to be treated differently, so it’s a case of being more conscious about how and when I shift.
I think I’ll try the KMC Hollow Link chain. My mate has a Kenevo which I’m sure uses a KMC and he’s not had an issue.
I’ll keep a stock of quick links though just in case!!

 

[Philly G]

Thanks all, looks like I need to adapt how I ride. Coming from an acoustic, I’ve never really considered shifting under load and just rode the bike. The ebike has to be treated differently, so it’s a case of being more conscious about how and when I shift.

Shifting under load is not good for acoustic bikes either. It's just that the consequences on an eeb can be more catastrophic because there's all that extra force going through the drivetrain

 

[Mikerb]

...also a bit more critical with 1x11/1x12 drivetrains....chains are narrower and chain angulation is greater.

 

[backcountry00]

Just picked up the KMC black tech ebike specific chain. Apparently it has reinforced joints to cope with extra loads. Fingers crossed it proves to be more durable than the Shimano and SRAM chains I’ve had so far!

 

[Darren]

I have a 2020 Trek Rail 9.8 XT, great bike but Its now destroyed 2 chains in less than 150 miles.
Gears shift nicely so don’t think there is an alignment issue.
First chain snapped when I applied too much power whilst changing gear in higher torque mode, LBS replaced original Shimano chain with a SRAM, and I just killed the new one when I changed gear pedalling up a hill. I’d gone from a high gear to low and from a standstill.

I get that there is more force on an ebike, and perhaps you have to be a little more careful when you change gear depending on power setting and terrain etc, but surely 2 chains in 150 miles isn’t right?
Has anyone changed their chain to something stronger? I’m running a 12 speed.
Cheers

What is your average cadence? Modern Shimano and Sram chains are supposedly designed to be shifted under load and whilst some mechanical sympathy goes a long way I believe too high a gear all of the time will decrease chain life as much as shifting under load.

 

[Jackware]

Just picked up the KMC black tech ebike specific chain. Apparently it has reinforced joints to cope with extra loads. Fingers crossed it proves to be more durable than the Shimano and SRAM chains I’ve had so far!

There's nothing wrong with the Shimano or Sram chains, as demonstrated by thousands being used on ebikes, only people with no mechanical empathy complain about them.

 

[KeithR]

Yep were still using chains designed for human powering, regardless of marketing. When you add human power and bike power and then shifting with load its gonna be a chain killer for sure.

Standard bike chains are built to take far more force through them than a human could ever inflict - they're plenty strong enough for ebikes, shifted properly.

Even my 30NM Levo SL in 80% turbo mode doesn’t sound good changing.

It shouldn't really "sound" at all - if you're backing off momentarily before you shift, which you should doing for any bike, powered or not.

 

[backcountry00]

There's nothing wrong with the Shimano or Sram chains, as demonstrated by thousands being used on ebikes, only people with no mechanical empathy complain about them.

There's nothing wrong with the Shimano or Sram chains, as demonstrated by thousands being used on ebikes, only people with no mechanical empathy complain about them.
[/QUOTE]
I’ve been riding acoustic MTB for over 10 years, I ride the bikes hard, including regular bike parks. Never have I snapped a chain and I must have had 7 different bikes over that time period. I also maintain my bikes meticulously, and I’d consider myself mechanically competent.
I’ve had an ebike for 2 months and gone through two chains. If my bike eats this new chain, despite my efforts to minimise this happening again, then it’s not rider error, there must be an issue with the bike.

 

[Jackware]

Of course ?

 

[Philly G]

then it’s not rider error, there must be an issue with the bike.

But you said in your first post, that your first chain snapped changing gear under power in high torque mode. I would say that anyone who rides an eeb like that can expect to snap a chain. If you don't let off the pedals and let the derailleur do its thing, that's rider error

 

[KeithR]

I’ve been riding acoustic MTB for over 10 years, I ride the bikes hard, including regular bike parks. Never have I snapped a chain and I must have had 7 different bikes over that time period. I also maintain my bikes meticulously, and I’d consider myself mechanically competent.
I’ve had an ebike for 2 months and gone through two chains. If my bike eats this new chain, despite my efforts to minimise this happening again, then it’s not rider error, there must be an issue with the bike.

But by the same token I've been riding MTBs for 20-odd years, ebikes for 4, and the only chain I've ever broken was way back, on an acoustic (fully rigid!) bike - and it was entirely down to me bollocksing up the shift.

This stuff has come up before, and there's just no consensus that ebikes eat chains - or we'd all be suffering:

My Specialized Levo eats chains

My Specialized Levo 9/2019 eats chains. My first chain, the original, was 75% after 750 km. I have replaced this for a Shimano 901 XTR chain this was 75% after 1250 km. I have now mounted my third chain, but now the front sprocket is apparently worn, because the chain does not release well under...

www.emtbforums.com

CHAINS! ?

It's probably been discussed before, but hey I'm new, so... My chain is phucked. I've done 93miles!! Surely that can't be right? I've a Haibike allmtn 2, running Yamaha motor, with 10x2 chain rings; On a local ride yesterday it threw the chain off the ring on motor overrun, 1st time on a...

www.emtbforums.com

I'm not daft enough to argue that the extra torque from a motor won't exacerbate the harm caused by poor shifting, but the underlying problem is technique, not technology.

 

[rstwosix]

I have to agree. I've done 3700 km on Shimano XT 11sp. Still running fine. My bike shop owner told me he has customers regularly wrecking drivetrain (on both regular & ebikes) through rider error/ignorance. One of the main problems is not using all the available gears and just pushing the high gears which results in worn out small cassette rings and snapped chains. Riding an ebike like that and adding turbo mode to the equation makes the whole disaster happen very quickly! Another issue he finds is dirty dry chains that have never been lubed.
There is nothing wrong with Shimano / SRAM chains if used correctly.

 

[wepn]

I’ve done a lot of miles on bikes & bikes and I’ve never ever broken a chain. Broken plenty of links though.

The problem isn’t the chain or the links. It’s the derailleur that shifts the chainline, twisting the chain - and link - with potentially more than 90 Nm of torsional forces for which it wasn’t designed. Poor technique doesn’t help.

Ask anyone who has an emtb with an IGH like a Rohloff or Kindernay how many chains (links) they’ve broken. Guaranteed none. Ok maybe somebody in the world has the requisite skills for that feat but they’d have to be truly special skills.

An IGH will save you $$$ despite the higher initial cost, not to mention less time in the garage and more time riding the bike.

 

[Gary]

The problem isn’t the chain or the links. It’s the derailleur that shifts the chainline, twisting the chain - and link - with potentially more than 90 Nm of torsional forces for which it wasn’t designed.

No it isn't!

when pedalling, torque is applied to the TOP of the chain NOT BOTTOM. And NOT THE DERAILLEUR. Even while shifting, the derailleur is under very little torsional force as it is designed to move pivotally in 4 planes all of which are sprung. And one of those springs is there primarily to create tension to the lower portion of chain.
The issue is when folk like the OP don't ease off while the chain is "derailling" from one sprocket to another and the actual chain is still between two sprockets but heavily loaded. This force is trying to pry link plates outwards. It's not specific to Ebikes either. it's just that noobs like the OP probably don't realise the consequences of the added motor assist or understand how motor over run works.

IGHs have many drawbacks too but IGH evangelists generally aren't worth arguing with about them.

 

[Gemini2k]

I’ve been riding acoustic MTB for over 10 years, I ride the bikes hard, including regular bike parks. Never have I snapped a chain and I must have had 7 different bikes over that time period. I also maintain my bikes meticulously, and I’d consider myself mechanically competent.
I’ve had an ebike for 2 months and gone through two chains. If my bike eats this new chain, despite my efforts to minimise this happening again, then it’s not rider error, there must be an issue with the bike.

Sorry to be the bearer of bad news, but you're shifting wrong. I can't count the amount of experienced riders I've seen who "know how to shift" make me cringe when I see them shifting on their e-bike. There's no other explanation other than some kind of weird faulty setup in your drivetrain, or very very bad luck getting 2 defective chains in a row, or incorrect installation. Bike chains are strong enough to hold a car under static load (12 Spd chains are around 3k pounds). Tensile strength is not their problem. The problem is side loads, I.e. shifting under load. You wear out the bushings, develop slop in the chain, and it falls apart from there.

Also, riding bike parks is also the least strenuous test for a bike chain, ha ha. A cat 1 roading probably puts more wear and tear in a single ride on a chain than a season of riding Whistler.

 

[wepn]

the derailleur is under very little torsional force as it is designed to move pivotally in 4 planes all of which are sprung

My head hurts from all the deja vu. Of course the derailleur is under very little force - never said it was -but it is the derailleur which shifts the chain - imparting twisting forces on the chain - under load. No Professor G?

 

[urastus]

There's nothing wrong with the Shimano or Sram chains, as demonstrated by thousands being used on ebikes, only people with no mechanical empathy complain about them.

Or there is something else at play in the OP's case. I agree with you on the chains though - finding a supposedly stronger chain is addressing the symptom, not the cause. And shimano has lots of tiny engineering going on with their chains and cassettes - ideally you want to keep them together.

 

[wepn]

IGHs have many drawbacks too but IGH evangelists generally aren't worth arguing with about them.

Funny I know a bike shop guy here who passionately dislikes Internally Geared Hubs. Personally I think it's because they never get booked in to the workshop. He doesn't like talking about them much either.

 

[urastus]

I’ve done a lot of miles on bikes & bikes and I’ve never ever broken a chain. Broken plenty of links though.

The problem isn’t the chain or the links. It’s the derailleur that shifts the chainline, twisting the chain - and link - with potentially more than 90 Nm of torsional forces for which it wasn’t designed. Poor technique doesn’t help.

Ask anyone who has an emtb with an IGH like a Rohloff or Kindernay how many chains (links) they’ve broken. Guaranteed none. Ok maybe somebody in the world has the requisite skills for that feat but they’d have to be truly special skills.

An IGH will save you $$$ despite the higher initial cost, not to mention less time in the garage and more time riding the bike.

if somebody is breaking chains, which is unusual, it would be good to find the cause before spending a small fortune on a rohloff hub and new wheel, chain tensioner, chainring, chain, rear sprocket etc

 

[Philly G]

if somebody is breaking chains, which is unusual

Not really unusual to be breaking chains if you shift under load, in turbo mode A Drivetrain is a fairly simple thing, if it's not set up right it will be noisy and not shift well, but nothing that would be causing the chain to break, unless the chain is too short of course. But then you might rip your derailleur off as well.

 

[backcountry00]

Thanks all for your comments.
I hope that this is rider error, as I’d rather that then there be an underlying mechanical issue with the bike. The bike doesn’t skip gears, so there are no indexing issues as far as I can see.
My riding buddy on a 11speed Kenevo hasn’t had this issue, and I’m pretty sure he’ll be changing gear as he would on his acoustic bike. Perhaps the 11speed chains are slightly stronger than 12 speeds?
I guess my fundamental point was ‘could this be a mechanical issue with my bike or is this to be expected on an ebike’? The resounding answer is rider error, which I’ll take on board and absolutely avoid shifting under load. I’m not ruling out an underlying issue however, as the chains should cope with an occasional change under load surely.
Still think the Trek Rail is ace though, having an absolute blast (when I have a chain ?)

 

[Philly G]

Still think the Trek Rail is ace though, having an absolute blast (when I have a chain ?)

Yeah I love my Rail as well! Hate the brakes though, can't seem to stop the front rotor rubbing/howling. Suspect a tiny bit of flex in the Yari could be partly to blame. Also had to warranty my BikeYoke dropper today Yes the 11 speed chain will be a little stronger, the more speeds, the narrower the chain has to be to fit between the cogs. Also I would recommend going back to a Shimano 12 speed chain, they did design that drivetrain to work together with the chain, mine seems to shift beautifully, just ease off the pedals for a second and it shifts.

 

[wepn]

Kenevo hasn’t had this issue

My head hurts from all the deja vu

Off-topic sorry - not exaggerating my head hurts much more now due to a heavy heavy Magpie direct hit. I wasn't wearing a helmet, nobody does around town here. Pretty sure it's the same big Alpha male bird that's swooped me before & of course he recognises me and does not like the Kenevo or any bike for that matter. This time it felt like an impact with a sack of potatoes and it feels like mild concussion. Helmet on in breeding season from now on.

 

[urastus]

zip ties and branches work. Eyes do too, but they have to be good eyes, not questionable texta circles that could be anything.

 

[urastus]

Thanks all for your comments.
I hope that this is rider error, as I’d rather that then there be an underlying mechanical issue with the bike. The bike doesn’t skip gears, so there are no indexing issues as far as I can see.
My riding buddy on a 11speed Kenevo hasn’t had this issue, and I’m pretty sure he’ll be changing gear as he would on his acoustic bike. Perhaps the 11speed chains are slightly stronger than 12 speeds?
I guess my fundamental point was ‘could this be a mechanical issue with my bike or is this to be expected on an ebike’? The resounding answer is rider error, which I’ll take on board and absolutely avoid shifting under load. I’m not ruling out an underlying issue however, as the chains should cope with an occasional change under load surely.
Still think the Trek Rail is ace though, having an absolute blast (when I have a chain ?)

I'd be giving the bike the once over. Alignment - is the chainring straight? What does the chain look like (alignment wise) when it is in a gear that is close to lined up with the chain ring? Raise the rear wheel and work the chain while you keep an eye on alignment (no motor). You know, just try checking different things. It could be that the rear wheel isn't aligned? Like a frame issue during manufacture. Industry isn't perfect. Without the motor on and the rear wheel raised you might hear something while you're running the drive train. Feel for movement in the cluster and the wheel bearings, and the pivot points. If you have something like a builders level (you just need something straight) you can use it to check wheel alignment - hold the level horizontal to the ground and against the side of the rear tyre so that it touches the forward side and the rear side of the rear tyre, kind of in line with the bike - you should be able to see if the level is pointing at an angle out of align with the bike. What are the gaps like between the tyre and the stays of the rear triangle? Do they look equal? You can also try to support the bike standing up straight with the front wheel in line, then get 5 meters or so behind the bike, squat down and check rear wheel alignment that way (I used to do it this way for motorcycles after tightening or loosening the chain). Just do all those basic checks so that you feel comfortable it isn't the bike. Run through the gears while the rear wheel is up too - your hanger might be out of align / bent. How do the cluster and chain ring look? Is the chain breaking at the joining links? They do have to face the right way (I assume you know this).

 

[Jackware]

zip ties and branches work. Eyes do too, but they have to be good eyes, not questionable texta circles that could be anything.

OMG, that was a scary video, though I couldn't stop laughing at her reaction ?