How long should my ebike chain last?

[John F]

My chain driven ebike is 5 months old and done 630 miles. The chain has been well lubricated all this time and the bike has never ventured off road. The chain is now shot.

The chain is marked:
KMC Z 2C-3 (it has 126 links)

The cassette is marked:
Shimano HG Hyperglide (7 speed 14 - 28 teeth)

On the KMC Website
http://www.kmcchain.eu/

it suggests for an e-bike the X10e chain:

“X10e
Specially designed for middle engine driven e-bikes such as Bosch, Panasonic and AEG, these chains have higher torsion resistance to cope with ruthless shifting and hi-torques”

Some questions:

1) It would seem I have the wrong chain for the job?
2) What is a reasonable expectation of life for an ebike chain? In my view, a chain and cassette wearing out in such a short space of time, and within the guarantee period, is unacceptable.
3) Has anyone any suggestions on this, re cassette and chain choice, specifically for an ebike?

 

[Artstu]

You've discovered the achilles heel of crank drive. I got about twice that distance from my wider hub chain. KMC seemed amazed by how many miles I'd done I'm on a slightly narrower X1 now on their recommendation http://www.kmcchain.eu/products-single_speed-3_32_hi_performance

Only time will tell if it is any better than the original basic KMC chain.

 

[mike killay]

I have twice fitted new rear sprockets within two years on my Tonaro, but only one chain.
The problem that I have is that the top rear cog is only 11 teeth and these are notorious for wearing.
Frankly, I think ebikes probably have too many gears and that about 5, with wider cogs and chain would be ideal.

 

[Deleted member 4366]

The chain is a service part, so not covered by the warranty, unless maybe it snapped on the first day. It'll be interesting to see how long your new chain will last.

Chains seem to last forever on hub-motored bikes. I've never had to change one yet. The one on my Giant BPM has done 3000 miles so far.

 

[John F]

I have twice fitted new rear sprockets within two years on my Tonaro, but only one chain.
The problem that I have is that the top rear cog is only 11 teeth and these are notorious for wearing.
Frankly, I think ebikes probably have too many gears and that about 5, with wider cogs and chain would be ideal.

Well it's clear that the normal chain is not up to the increased loading of an ebike then. I wonder if manufacturers know this or even care? I have never used all 7 gears anyway. It stays on 5 nearly all the time, so I'm hardly spreading the load out over the whole set

 

[John F]

The chain is a service part, so not covered by the warranty, unless maybe it snapped on the first day. It'll be interesting to see how long your new chain will last.

Chains seem to last forever on hub-motored bikes. I've never had to change one yet. The one on my Giant BPM has done 3000 miles so far.

I've informed the seller of this, and they are looking into this matter after I mentioned the KMC ebike specific chain to then, and will report back.
This is certainly an unexpected expense that I never anticipated.

 

[flecc]

It's become a much bigger problem with today's more powerful crank drives, bike chains were never intended to take such loadings long term, especially if the narrower derailleur ones.

There was much less of a chain problem with the original Panasonic crank unit which peaked at 400 watts and just about averaged 250 watts from the motor. Even that was only at very low cadences, much of their ridden life spent at less than half that contribution. Today's units can pump out 500 watts or more at any cadence or road speed up to 15 mph, or 28 mph on the S versions.

They really need a much larger chain and sprockets gauge like the old trade bike standard, preferably coupled with a NuVinci gearhub since epicyclic hub gears similarly suffer with crank drives and a wide chain rules out derailleurs. An alternative is a toothed belt drive like the Gates one.

 

[Kenny]

I agree with flecc that the high wear is due to more powerful motors.

My original 5 year old chain on my Pro Connect is still going strong with over 3000 miles.
My friend with the 350w version snapped his at 1000 miles.

 

[John F]

You have confirmed, what is really pretty obvious to me now, that a skinny derailleur chain would never be up to the job. It's just another aspect of ebikes that would put off potential customers if they knew. Another example is you shouldn't ride them in the rain!

So has anyone tried the KMC ebike specific chain? They do a 10 and 9 speed version (mine's a 7!) Check out the KMC X9e and KMC X10e. Expensive - but up to the job?

 

[sixpence_none_the_richer]

I agree, a wiider chain has to be better.

I do believe track bikes have the wider 1/8" size, the phychology being that those guys with enormous thigh muscles think that they would snap the chain if if was any narrower! But 1/8" used to be the norm before the demand for ever more sprockets at the rear. My old Raleigh 20 with steel chainwheel and cotter pins has the wider size. The steel chainwheel is surely going to be harder wearing than a lightweight alloy one, and with the internal gear hub rather than a derailleur the chain line is always going to be spot on making for better longevity of chain and sprockets.

 

[flecc]

So has anyone tried the KMC ebike specific chain? They do a 10 and 9 speed version (mine's a 7!) Check out the KMC X9e and KMC X10e. Expensive - but up to the job?

You can't use the 9 or 10 speed chains on your 7 speed derailleur. Not only are they less strong, they are too narrow and will not sit down properly onto your wider sprockets. The internal chain width of 9 and 10 speed chains is generally 11/128" (2.18mm) rather than 3/32" (2.38mm).

My suggestion is to use the highest quality 7/8 speed chain that you can buy, but not the Rohloff 24 carat gold plated one at £124.99 of course. KMC's equivalent of their recommendation for your bike is the X8 series. One problem to watch out for is that standard chains have only 114 or 116 links, too short for you, and that's true of the KMC X8. I tend to buy two of a brand/type that I can consistently get and use one for add-on bits for each successive purchase.

Here's the complete size listing:

Trade bikes = 5/32" chain roller/sprocket teeth width

Hub and Single gear = 1/8" chain roller/sprocket teeth width

Up to 8 speed derailleur = 3/32" chain roller/sprocket teeth width

10/11 speed vary by maker, so for all derailleurs it's best to measure the overall chain width:

3-8 speed - 7.2mm (all brands)
9 speed - 6.8mm (all brands)
10 speed - 6.2mm (Shimano)
10 speed (narrow) - 5.9mm (Campagnolo)
11 speed - 5.5mm (Campagnolo)

Bicycle chain pitch (rivet centre to rivet centre) is always 1/2".

 

[EddiePJ]

I didn't get much more than 500 miles out the chain on the Xtrem before it had pretty much reached the wear limit,, but resisted changing it for a further 200miles.

 

[trex]

it seems to me that chain wear varies from bike to bike.
Chains on crank drive bikes is an essential component and should be covered by guarantee.Any good supplier should replace it for you FOC.

 

[flecc]

Chains on crank drive bikes is an essential component and should be covered by guarantee.

As Dave has indicated earlier though, they are a consumable so not a normal warranty item. On a crank drive e-bike the usage is essentially abnormal for a bicycle chain, which weakens any claim.

 

[KTM Bike Industries UK]

it seems to me that chain wear varies from bike to bike.
Chains on crank drive bikes is an essential component and should be covered by guarantee.Any good supplier should replace it for you FOC.

never going to happen I'm afraid...

warranty is to cover manufacturing faults.

wearing a chain out is not a fault.

Itd be like trying to claim new tyres or break pads that have worn out.

 

[trex]

john,
does the chain sit on the rear cogs properly?
if it does not, how many links are out?

colin,
I think manufacturers should tell their customers what is the average expectancy for the chain on a crank bike, for example, 1200-1500 miles for 90kgs riders. You ought to know the figure.
If the wear is substantially above average, then it's only fair that it's replaced FOC for the customers.

 

[shemozzle999]

Hi John F

Why do you think your chain is "shot"?

Please can you post some pictures showing the chain and highlight the defects so that others will know how to check for them.

 

[KTM Bike Industries UK]

colin,
I think manufacturers should tell their customers what is the average expectancy for the chain on a crank bike, for example, 1200-1500 miles for 90kgs riders. You ought to know the figure.
If the wear is substantially above average, then it's only fair that it's replaced FOC for the customers.

I'd love to be able to agree with you, but I'm afraid there isn't an average, and as its a part that is easily damaged by riders changing gear badly, not looking after it, taking the wheel in out, riding in a massive gear etc etc. I'm afraid you'll never get a brand of chain offering to warranty their product against wearing out.

we've had a customer recently contact us (not eBike customers) because their dealer wouldn't warranty their cranks because the paint had worn off where their shoes rubbed it. I'm afraid wearing a chain out comes under the same category.

Its not a manufacturing fault, or indeed one that any customer can reasonably claim or prove how many miles they have done, so no chain brand will warranty one for wearing out, especially on a crank driven eBike.

Col

 

[trex]

then there should be a guide in the bike manual or website support showing how to care for the bike chain. Manufacturers should not blame their customers ignorance to avoid replacing worn out essential components during warranty period.

 

[KTM Bike Industries UK]

that is true...

in ours it says this:

Exchanging Intervals for Chains and Cogsets
Chains should be renewed after 1500-3000 km in order to avoid unnecessary wear of the chainrings and therefore increased costs! The chain’s mileage de- pends on the use-intensity and the care. Let your KTM dealer check the chain and the cassette regularly�

but that doesn't mean you can claim for a new one if yours doesn't last 1500km.