When should l replace my chain?

[Coolcmsc]

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.

Sure. But then 10 and 11 speed cassettes are quite cheap and increasingly rare in the (expensive e-mtb) scheme of things.

The real issue is with 12 speed stuff…. Look it up ?

 

[Istari]

For 12 speed cassettes you can by individual sprockets too.

 

[ggx]

mY .50CTS. On e-bike use drive train until it´s done and replace everything. Mixing new and old parts ins´t going to work 100% . My actual e-bike is reaching the 3000km mark with original XT drive train and still runnig. End off summer is going to have fresh stuff.

 

[Coolcmsc]

For 12 speed cassettes you can by individual sprockets too.

Your‘re kinda correct, but I think the way you say it May be exceptionally misleading.

I thought that Shimano 12 speed 10 and 12 tooth sprockets could be replaced, but they’re not the ones that commonly need replacing on an e-MTB bike. You imply the larger rings which much more commonly wear on e-mtbs with a worn chain can also individually replaced. I’m don’t use 12 speed Shimano, so if you could point us all to a good reference, that would be brilliant and might tempt me to convert — maybe a shop-site selling larger 12 speed Shimano sprockets and a website/YT tutorial explaining.

Concerning SRAM 12 speed GX / Eagle, their sprockets simply can’t be replaced due to their construction, at least within guarantee. Perhaps you are aware of some of the rather clever hacks being undertaken by one or two trials riders on the largest ring involving an e-Thirteen part. But that requires skill and being happy to void all warranty. I think Ali Clarkson may have a YT on that.

Of course we all know about the e-Thirteen Helix and earlier TRX+ cassettes. The TRX comes in two replaceable parts, one half aluminium and one half steel and it’s a debatable point as to whether this is cost effective for e-MTB bikes. The Helix is more modular and a cost effective investment if you have a normally aspirated with a 12 speed SRAM GX / Eagle system, but it’s obviously not suitable for e-MTB bikes.

 

[Istari]

Of course, not all individual sprockets can be replaced on a all cassettes, some of the larger ones are connected with each other. As I wrote, which gears will wear out faster depends on the style and terrain of driving. In tour riding, the smallest ones, while on mountain climbs, the larger ones. In addition, the largest ones are often made of aluminum not steel - they will wear out faster, so some people should also pay attention to it. I saw all replacement sprockets for Shimano 11 speed in stores, but for 12 speed so far I've only seen the smaller ones, I don't know where you can get larger sprockets.

Either way, people should know that it is possible to replace the sprockets in the cassette.

 

[Coolcmsc]

Of course, not all individual sprockets can be replaced on a all cassettes, some of the larger ones are connected with each other. As I wrote, which gears will wear out faster depends on the style and terrain of driving. In tour riding, the smallest ones, while on mountain climbs, the larger ones. In addition, the largest ones are often made of aluminum not steel - they will wear out faster, so some people should also pay attention to it. I saw all replacement sprockets for Shimano 11 speed in stores, but for 12 speed so far I've only seen the smaller ones, I don't know where you can get larger sprockets.

Either way, people should know that it is possible to replace the sprockets in the cassette.

So, in summary, what you meant to say is what we all know, namely that for all makes of 12 speed cassettes the ability to change sprockets is very limited and probably of no value to emtb riders.

This is an emtb forum. That’s why I said there’s a big problem with poor availability of 12 speed cassettes in the U.K. and I‘m still struggling to understand your point, sorry if that’s just me….

 

[Istari]

From my perspective on most e-mtb, due to the higher torque, the smallest sprockets wear out the fastest, so for owners of 12 speed the possibility of replacing the smallest sprockets is the most valuable information

 

[Sander23]

I've been doing that for the past 7000 km.
My experience is that with my xt 11 speed drivetrain it will work but only 2 time (changing the smaller sprockets), 3th time there was some play in the cassette with I couldn't get solved with a new chain and sprockets.

Switched to sram ex1 and haven't had it ever since! Mainly because the 5 highest gears are made out of 1 block steel and the 3 lower sprockets made of 3 separate steel sprockets ( replaceble in 1 set).

 

[Beekeeper]

If I were to change my chain on an 11 speed cassette at 0.5% each time, how many chains per cassette could I get before skipping was a problem?

I managed 2 chains when replacing at 0.75. The third chain skipped and was not accepted.

 

[Coolcmsc]

If I were to change my chain on an 11 speed cassette at 0.5% each time, how many chains per cassette could I get before skipping was a problem?

Great question. Have a look at the link I posted earlier in the thread (https://zerofrictioncycling.com.au/wp-content/uploads/2017/12/RRG.pdf). I’m sorry to say it’s a ‘long read’, great for insomniacs, but the answer to your question is there in terms of cost ($) for each type of bike and each type of riding in dry and wet (muddy for MTB) conditions.

The experiments were over a long duration. I’m not aware anybody else has published equivalent info, although of course the manufacturers will know for themselves and all competitors (they won’t tell us ?). There’s heaps of stuff online for much shorter experiments which I’m sure are accurate in what they are testing, but the ones I’ve found over the years use conditions that don’t represent real life.

The article I’m referencing sets out every aspect of the experiment which replicates how a chain is used over a few years, including times of routine lubrication, less frequent episodes of deep cleaning, periods of light contamination riding and periods of heavy contamination riding, in the wet and in the dry. Real life then for each type of bike riding. This is why the document is so long. Elsewhere on the website, there’s some videos worth looking at and an Excel spreadsheet to download if you want to examine every aspect of the data or perhaps change the cost of components to see what effect that has on the answer to your question.

But you will have to read it ? ? ?

The data published is for 10,000km‼They acknowledge that this is several years for most riders, but put the genuine answer to your question as their priority. For example, they publish the prices that they used for their cost calculations (they’ve all gone up since ?). The website has lots of info. I have no connection at all. They are in Australia. They sell wax-prepped products and I’m going to guess they supply a lot of stuff to the race market because whilst interested in drive-chain wear (full data published), they seem to be most interested in every aspect of friction.

Finally, I make no apology for some repetition above and the absurd length of my comments in this thread. But this topic is one of the few that has decent real-life research available to counter our day-to-day prejudices. We get so excited about protecting and maintaining our other bearings on the bike. But they’re all sealed and lots of effort is made to keep them out of the way of the gunk.

Our chains are not sealed, the number of articulations at the bearings per ride is absolutely mind bogglingly large, a massive load is placed through these bearings — especially on an e-MTB — and in the worst conditions, the chain is literally continuously hosed down with wet grit using a pressure system called the front wheel.

Imagine what we’d say about all the bike’s bearings being treated like that and not being cleaned and lubricated afterwards….

 

[Gyre]

Your‘re kinda correct, but I think the way you say it May be exceptionally misleading.

I thought that Shimano 12 speed 10 and 12 tooth sprockets could be replaced, but they’re not the ones that commonly need replacing on an e-MTB bike. You imply the larger rings which much more commonly wear on e-mtbs with a worn chain can also individually replaced. I’m don’t use 12 speed Shimano, so if you could point us all to a good reference, that would be brilliant and might tempt me to convert — maybe a shop-site selling larger 12 speed Shimano sprockets and a website/YT tutorial explaining.

I'm seeing more reports from folks (here and in various FB groups) that the cogs that they've worn out are the smaller ones, not the larger ones.

 

[Coolcmsc]

I'm seeing more reports from folks (here and in various FB groups) that the cogs that they've worn out are the smaller ones, not the larger ones.

Well, that’s good to hear, especially for Shimano users, thanks!

 

[HarveyMiller]

Actually, it's all road riding.
Average amount of climbing (1800 feet/45 miles).

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?