When should l replace my chain?

[lightning]

My Ebike has now done 600 miles. According to my Park Tool chain checker the chain was initially at 0.25 but is now at 0.5

The tool says "new chain 0.25, replace at 0.75"

But l've read somewhere that Ebike chains should be replaced at 0.5

lt's a SRAM 12 speed drivetrain and the chain is nearly £80 at my LBS (plus no stock until July)

However l've bought a "GX Eagle" 12 speed SRAM chain from Ebay for £26 and l take it this will be fine.

Should l replace the chain now, or wait until it reads 0.75?

 

[7869hodgy]

I had 1900km off my first e-bike chain. My jockies were very, very worn too but still worked. I swapped the whole drive chain at 1900km without any breakages......just thought I’d be chancing my arm if I tried more.

Stop measuring and fretting - go ride.

Have a spare link on you in case of a break but enjoy the bike.

I sold my first ebike and the guy broke the 400km chain the next day. I have no idea how.

Keep the chain clean and lubed and you’ll be Gucci.

 

[Beekeeper]

Anything above 10 speed you should change at 0.5
10 speed and below, change at 0.75

what is the price of a new cassette for your bike? How does compare to the price of a chain?

 

[GDAS]

Park Tools say for 11 or more speed chains (regardless of whether the bike has a motor), you should change at 0.5% wear. If you do so, you'll get longer life out of your cassette and front ring. Alternatively, just relax and run the whole drivetrain into the ground, i.e. ride it until the first component gives up and then replace the lot, it's a fairly common approach.

 

[Nicho]

My jockies were very, very worn too but still worked

Maybe you should try boxers next time!

 

[Aikone]

I’ve been running chains to 0.75 for years, seems to work fine. I keep the chain checker with the cleaning kit and check it every drivetrain clean.

 

[lightning]

Well, l think l will replace the chain at 0.5 if that's what it says.
The cassette is over £200 unlike my 11 speed where an XT cassette was around £60

The chain didn't last long ☹
l've looked after it, have completely degreased and re oiled the chain three times as well as regularly wiping it down and oiling it.

l guess if the GX Eagle chain at under £30 is satisfactory l might as well just change it every 500 miles or so.

This is the chain checker l am using, it take it this is still OK, l bought it ages ago when l was running 10 speed

 

[lightning]

I’ve been running chains to 0.75 for years, seems to work fine. I keep the chain checker with the cleaning kit and check it every drivetrain clean.

ls that with 11/12 speed? With 10 speed it's perfectly acceptable to replace the chain at 0.75

 

[Aikone]

ls that with 11/12 speed? With 10 speed it's perfectly acceptable to replace the chain at 0.75

It’s with XTR 12 speed, I’m on chain number 2 with this cassette.

Seeing your checker photo, does it have two pins on the underside that drop into the chain? If it does it’s worth keeping an eye on them as we used to find in my shop days over time they would bend and give a false reading.
I’m 25 years in with one of these!

 

[7869hodgy]

Is it the drivetrain manufacturers recommending you change at 0.5% ?

 

[Coolcmsc]

Is it the drivetrain manufacturers recommending you change at 0.5% ?

No. Absolutely not. Although the added drive train wear found in e-bikes is certainly to their advantage for increasing the sale of drive train spares.

And this lower figure (0.5) is NOT about when the chain will break — it just isn’t.

The 0.5 figure for e-bikes is all about when wear on the cassette teeth starts to increase more rapidly from the rate when it’s less than 0.5 (wear per mile starts to increase rapidly after 0.5). In some countries, sourcing any 12 speed cassette is getting difficult. The same is true for the chain ring teeth, but obviously that isn’t too expensive to replace — this all about cassette wear.

The chain gets longer because the bearings between each link wear down (it doesn’t stretch). As a result of this, the rollers at each bearing engage differently with the cassette teeth as the chain lengthens. This is true for all bikes.

Due to the extra power of an e-bike the effect this has on cassette tooth wear jumps up unacceptably at a smaller increase in chain length (0.5) on average than a normally aspirated bike. So the adverse consequences of chain length wear happen sooner on e-bikes.

The chain doesn’t ‘have’ to be changed until the chain starts slipping on the cassette teeth so much that it’s no longer fun or safe to ride the bike.

It‘s advised to change the chain at 0.5 on e-MTB’s because if you do some calculations about replacement costs for a drive train over about 2 to 3 years, it works out much much cheaper to keep change your chain at 0.5 without doing any more worrying.

Of course, the most important thing to do is slow down the increase in the chain length (wear) so it takes much longer to get to 0.5. For any given person on their bike riding the same trails in the same way, the only good way to do this is be obsessive compulsive about cleaning your chain well and that requires getting the ‘micro-grit‘ out of the space between the rollers and the pins — essentially other aspects of cleaning are cosmetic by comparison. YT vids and forum posts here give advice on that.

A few boast entirely fairly that they get well over 1000km even over 2000km from a chain and then don’t have to change the cassette due to gear slippage, all without really cleaning the chain correctly. Well, I for one am jealous and pleased for them. They obviously ride in a way that many are unable to. I think their experiences shouldn’t guide me at least ?

I’ve not heard the 11 vs 12 speed thing tho’ — I’d be interested to hear others’ opinions on that.

 

[lightning]

l've managed to get two spare chains so at 700 miles l am going to fit a new chain.

 

[HarveyMiller]

I would replace at 5 but find a way to slow chain wear, as follows:
For me, though, my experience has been amazing in this regard. I use Rock and Roll Gold and fully apply and wipe clean every 150 miles. My chain, with now over 4,000 miles on it has only experience stretch by 1/100th of an inch! Yes, amazing! I use 3 chain checkers, including the electronic chain caliper and find it hard to believe but, after talking with my local bicycle mechanic (very busy) he confirmed that he's seen these kinds of results.

 

[lightning]

Thank you, that product is available in the U.K. so l will give it a try.

 

[Coolcmsc]

I would replace at 5 but find a way to slow chain wear, as follows:
For me, though, my experience has been amazing in this regard. I use Rock and Roll Gold and fully apply and wipe clean every 150 miles. My chain, with now over 4,000 miles on it has only experience stretch by 1/100th of an inch! Yes, amazing! I use 3 chain checkers, including the electronic chain caliper and find it hard to believe but, after talking with my local bicycle mechanic (very busy) he confirmed that he's seen these kinds of results.

Impressive!
On an e-bike off road on trails I’m assuming.
Do you do a lot of decent climbing as part of those miles?

 

[B1rdie]

I keep the chain clean as a means to have it roling silent and smoothly, not believing it will last longer. What will determine the longevity of the chain, on an ebike, is the amount of stress it suffers due to the extra torque of the motor, so that a chain will last longer if ridden on eco mode than on boost, no matter how clean or dirt it is.

 

[lightning]

I clean my chain regularly and managed 700 miles before it reached the wear limit of 0.5

l don't know if this is good or bad, but unless l can improve on it l will be going through six chains every year.

 

[Beekeeper]

I clean my chain regularly and managed 700 miles before it reached the wear limit of 0.5

l don't know if this is good or bad, but unless l can improve on it l will be going through six chains every year.

how about putting a second chain on at 0.5 and running it until 0.75 and then put the first chain back on and run it into the ground

 

[Gyre]

0.5% is aggressive, but cassettes are so pricey these days I'd do the same. Unless I'm mistaken, it's not like there are a lot of choices for chainring sources as well, so preserving the chainring is important.

 

[lightning]

Yes unfortunately the cassette is currently not available so l need to preserve it.
Not sure about chain ring availability.

However, when the cassette does get worn (and won't take a new chain) l will do as suggested above, refit the old chain and run it for as long as it carries on working.

And then replace the chain, cassette and front chainring.

 

[Coolcmsc]

Once the cassette and / or the chain ring start to wear much faster, each worn chain becomes closely matched to each worn cassette and chainring due to the unique wear pattern they generate together. So, matching an older chain to an older cassette that got worn with a different chain often (not always, obviously) lead to chain slip.

This is also why a new chain put on a well worn cassette often slips and jumps off the teeth under load, even though the old chain just removed wasn't doing that at all.

The lesson from this is that if you use a system of swapping chains and cassettes as mentioned above — which is a strategy that provides some reduction in cost over 2 to 3 yrs, even if it’s not the best strategy — then you must find a way of pairing up chains and cassettes/chain rings for it to be cost effective (= reduce costs whilst avoiding slipping cogs).

This is all just piffle though when compared to the much greater benefit of regularly cleaning your chain fully (= not just cleaning the bits you can see which makes no meaningful difference, but getting the micro-grit from between the roller, the pin and the inner face of the outer side link and the outer face of the inner link.

If anybody’s actually got this far and still has the energy to know more, here is a link to thoroughly evidenced-based information on how cycle chains wear, why they wear and how to stop them wearing so fast. Did I say it was evidenced based? I should have, ‘cos it is….

It’s 65 pages long (!) with lots of explanatory pictures and tables. Elsewhere on the website there’s an Exel spreadsheet that compares the impact on chain wear over time for a large number of products. There’s also data for those interested in that last watt of energy when racing on road, XC and MTB where the friction from different chains and the durability of different chains for 10, 11 and 12 speed is also set out There’s other info and a very expensive shop — it’s in Aus.

I’d recommend it as a cure for insomniacs!

https://zerofrictioncycling.com.au/wp-content/uploads/2017/12/RRG.pdf

 

[lightning]

l had a look through and it makes depressing reading!
The basic conclusions are as follows

Most chain lubes aren't very good at preventing chain wear

The only thing you can really do that's any good is remove the chain and immerse it in hot wax

lf you race
Put on a brand new chain for race days

 

[Coolcmsc]

l had a look through and it makes depressing reading!
The basic conclusions are as follows…

Cripes, I didn’t think anybody would actually read it, well done

And I’d add to your summary that they are also explicit — with explanations — about the importance of cleaning and how that interacts with the different lubricants available.

 

[B1rdie]

I took the advise from Olinto, the guy made three around the globe bike trips. He says that lubing a chain only helps grit to stick to it, in the end, increasing wear, and forcing you to use chemical products to clean it.By his experience, rinsing the chain after each day and drying it was the means to keep a chain rolling for best mileage.

 

[lightning]

lt's true that chain oil just makes the dirt stick to it.
More of an issue on MTB than road bikes.

l did try cleaning and then not oiling the chain once, but the chain went rusty and had stiff links.

Maybe spraying with a light lubricant such as WD-40 or GT-85 would prevent that.

l will give it a try and see how long this chain lasts.

 

[Coolcmsc]

I use the method in the following video. It’s moved me on from a heavy user of chains on my emtb to a lighter user. For example, my current chain hasn’t changed length at all after nearly 600km and 10,000m of hard climbing (not fire roads then) over 3 months in the gritty Peak District (U.K. gritstone area for those overseas).

 

[HarveyMiller]

I think WD40 is terrible for chains. It's more solvent than lube and does the opposite of what you'd want it to do.

lt's true that chain oil just makes the dirt stick to it.
More of an issue on MTB than road bikes.

l did try cleaning and then not oiling the chain once, but the chain went rusty and had stiff links.

Maybe spraying with a light lubricant such as WD-40 or GT-85 would prevent that.

l will give it a try and see how long this chain lasts.

 

[Istari]

Why replace the entire cassette if you can buy specific cassette sprockets cheaply? On e-bikes, the smallest 2-3 sprockets are often used the most (depending on the driving style), which are easy to replace (cost about 6-7 euro). Only the largest cassette sprockets are so expensive that it is often more profitable to replace the entire cassette.

 

[lightning]

l didn't know you could buy cassette sprockets individually.

 

[Gyre]

l didn't know you could buy cassette sprockets individually.

In another thread someone posted part numbers for Shimano 10-tooth and 11-tooth cogs. Like a lot of things they do seem hard to find, and probably moreso because eMTBs chew through them pretty quickly.