Relative costs of chains and cassettes

[Snoozeboy]

I've often read or watched YouTube to receive advice that it's better to change a chain before it's too worn, because when worn it wears the cassette prematurely and cassettes are much more expensive.

New chains cost about 40chf, a new cassette about 65chf, plus the drive wheel for a Bosch, 20chf, not a big difference.

Am I missing something?

 

[Indigo]

40chf is much cheaper than 125chf (40+65+20), that's over 3x more. The difference is much greater when using more expensive drive chain components (eg. SRAM XX1, Shimano XTR).

 

[Snoozeboy]

I get what you're saying, for more expensive components.

For my level of stuff e.g Shimano XT, it doesn't seem to work.

I just changed a chain at 600km and 0.75 stretch. The new chain, which is the same kmc E11 as the old one, skips gears on the old cassette, despite trying to adjust it. On my first ride it even jumped into the spokes and took the derailleur with it, mangling it. So, changing the chain early prolonged the life of a 60chf cassette but it cost me a 90chf derailleur.

I think for expensive stuff, better to change the chain, but in future I think I'll let the chain play out until it skips too much then change the whole drivetrain. I guess there's a higher risk of snapping the chain, but this is less likely to cause a crash on an ebike as there's less power from the rider going through the chain.

As an aside, I once broke my collarbone falling off my clockwork road bike when my chain snapped under a lot of power (I was young and fit in those days), throwing me off balance. I was lucky. If I'd fallen the other way on the next pedal stroke I would have fallen into traffic on a main road.

 

[steve_sordy]

I have had my first emtb since Jan this year and I've only done 380 miles, so I have time yet to discover whether my usual chain strategy works for emtbs as well as it has worked for clockwork bikes .

I don't use a Go/NoGo gauge that only tells you whether it is less or more than two specific wear points. Instead I use a vernier caliper to measure the chain as it slowly extends as the pins wear. (You could remove the chain and measure with a metal tape measure over a longer length to get the same accuracy.) Once the chain gets past 0.65% I replace it with a new one. So far I always manage to use up a third chain before things start to go wrong. A fourth new chain will seldom run on the cassette. but replacing the third one works until I can get a new cassette. I could keep running that third chain/old cassette combo, but I don't want to put up with the shifting problems - however slight. Also, a worn chain transmits wear to the rest of the drive train and the worse the chain is the faster it does that.

For years, riding where I ride and how I ride, I was getting an average of 650 mile per chain (9, 10, 11 speed). Then I bought a bike with the SRAM Eagle 1x12 system. It has a mix of X01, X1 and XX1 kit. So far, I've done over 1400 miles on it with the XX1 chain only stretching 0.25%. I accept that on a clockwork bike I'm not putting as much torque through the system, but even so, that is an impressive difference!

In fact now I've thought about it, I will go check the wear on my emtb's chain.

Edit: Just done it. I've got 0.15% length extension after 379 miles (606km)

PS: If your chain is wearing quickly and affecting the cassette, don't forget to check the front ring and the jockey wheels. I have pictures of badly worn rings and jockey wheels that are so bad you would wonder how they worked!

 

[OlaGB]

I just changed a chain at 600km and 0.75 stretch. The new chain, which is the same kmc E11 as the old one, skips gears on the old cassette, despite trying to adjust it. On my first ride it even jumped into the spokes and took the derailleur with it, mangling it. So, changing the chain early prolonged the life of a 60chf cassette but it cost me a 90chf derailleur.

I think for expensive stuff, better to change the chain, but in future I think I'll let the chain play out until it skips too much then change the whole drivetrain.

I think you`re on to something, that its probably cost saving doing it something like that.

I`m testing stock KMC chain vs shimano CH-E8000 chain on my 900E now, doing 200km on each then swap to see whitch wears out first. Considering running them way out of spec, and then do cassette/chain(s)/crank cog all together, but not decided yet.
Only 450km in to it yet (4-5 weeks of biking), and seeing some wear on the cassette allready. Chains still ok ofcourse.

 

[Snoozeboy]

PS: If your chain is wearing quickly and affecting the cassette, don't forget to check the front ring and the jockey wheels. I have pictures of badly worn rings and jockey wheels that are so bad you would wonder how they worked!

Thanks for your reply. I don't see how a worn front ring can prematurely wear the chain. As far as I'm informed, a chain stretches when the rollers wear on the pins, which reduces the diameter of the pins, which both lengthens the chain and weakens the pins. Worn cassettes and chain rings can only affect the rollers, but the effect on the pins is unchanged from an unworn cassette/chain ring.

In other words, I can see how a worn chain can prematurely wear a cassette and chain ring, but I can't see how the converse could happen.

On a 1x system, if my understanding above is true, I'm not even sure of the wisdom of changing the chain ring with the rest of the drive train, unless the chain ring is so worn that the chain slips on the chain ring.

 

[Russell]

On my first cassette I got 2 chains and 1000 miles , I tried a third chain but it wouldn't run without skipping. I have just put a third chain on my second cassette and it's working just about but not nice.
Trouble is now my wheel bearings are shot at 1800-1900 miles. This is all slx bits.

 

[Snoozeboy]

Only 450km in to it yet (4-5 weeks of biking), and seeing some wear on the cassette allready. Chains still ok ofcourse.

When you say you're seeing wear, is the chain slipping, missing/skipping gears or is it just purely visible wear, i.e. scalloped teeth?

 

[OlaGB]

Only that i can see backside of the teeth changing its shape, on the most used cog`s.. Not alot, only starting to see it.
Nothing visible on the crank cog yet.

 

[steve_sordy]

Thanks for your reply. I don't see how a worn front ring can prematurely wear the chain. As far as I'm informed, a chain stretches when the rollers wear on the pins, which reduces the diameter of the pins, which both lengthens the chain and weakens the pins. Worn cassettes and chain rings can only affect the rollers, but the effect on the pins is unchanged from an unworn cassette/chain ring.

In other words, I can see how a worn chain can prematurely wear a cassette and chain ring, but I can't see how the converse could happen.

On a 1x system, if my understanding above is true, I'm not even sure of the wisdom of changing the chain ring with the rest of the drive train, unless the chain ring is so worn that the chain slips on the chain ring.

I didn't say that a worn front ring can prematurely wear the chain. What was it I wrote that made you think that? If you let me know I will change how I wrote it to avoid anyone else coming to a similar conclusion.
When a chain is worn and it has worn with the rest of the transmission, then they can rub along relatively happily. The shifting may be a bit crap, and you might get chainsuck, but at least they will transmit the torque. I agree that as the pins wear and the chain lengthens, the rollers no longer just drop in to the base of the tooth (cassette or ring), but slide about trying to fit in. This accelerates the tooth wear quite markedly. It also wears the outside diameter of the rollers from the friction. But roller wear does not extend the chain length. Nor does the outside diameter of the pin rubbing on the inside of the roller. It is only where the pins are in contact with the side plates that pin wear lengthens the chain.
But as the chain lengthens it wears the teeth out. Eventually, when you put on a new chain, the half inch pitch chain no longer slots nicely into the teeth. The faces of the teeth are now so worn that the new chain is not in full contact with as many teeth as before. The entire force you are putting into the chain is now borne by very few teeth and very few rollers. Something has to give! What gives is that the chain slips and skips a few links. Everything works fine in the garage when you first fit the new chain, the changes are smooth etc. But that is under zero load. As soon as you get on the trail, the chain skips and bangs and can be unrideable. A temporary cure is to refit the old chain until you can get a new front ring or cassette, whichever is giving the problem.

 

[steve_sordy]

Just edited my post above (#4) with the chain wear after 379 miles (606km)

 

[Snoozeboy]

I didn't say that a worn front ring can prematurely wear the chain. What was it I wrote that made you think that? If you let me know I will change how I wrote it to avoid anyone else coming to a similar conclusion.

You're right. I misconstrued this, "PS: If your chain is wearing quickly and affecting the cassette, don't forget to check the front ring and the jockey wheels. I have pictures of badly worn rings and jockey wheels that are so bad you would wonder how they worked!"

 

[steve_sordy]

These pics of worn gears and jockey wheels may be helpful.

Below: Worn ring (some teeth missing too). A new one is in the background. A new chain worked fine on the street, but would not run under power on the worn ring. The ring had to be changed trail side at Cannock!

Below: Jockey wheels: (Spot the worn one!) Shifting was improved after the change, quieter too!

Below: Gear showing shark toothing and also the burrs created as the rollers push the tooth material out of the way. The burring happens as the chain wears and fewer and fewer teeth are in full contact with the chain. Filing off the burrs can reduce chain suck enough to ride, until you can replace the gear. (I did that on a cassette with some success, lasted long enough). This is a front granny from a 2x, but exactly the same wear and deformation can happen on any of the gears on the cassette. I have seen it on my cassettes, but not as bad as this. The gears are both 24T Shimano. Difficult to believe how badly they can wear isn't it, and still work!

 

[Russell]

What are you using to oil the chain?

 

[steve_sordy]

What are you using to oil the chain?

Finish Line Wet lube when it's wet and Finish Line Dry when it's dry (not so often these days).
I use my Parktool chain cleaning device from time to time as well. Maybe as much as 3 x per year!

 

[Ross1137]

Wg

40chf is much cheaper than 125chf (40+65+20), that's over 3x more. The difference is much greater when using more expensive drive chain components (eg. SRAM XX1, Shimano XTR).

What the hell is chf?? Could google it I suppose.....

 

[AdamDuckworth]

Wg
What the hell is chf?? Could google it I suppose.....

Swiss Francs I believe...

 

[steve_sordy]

Swiss Franks definitely.

 

[RoJo]

I get what you're saying, for more expensive components.

For my level of stuff e.g Shimano XT, it doesn't seem to work.

I just changed a chain at 600km and 0.75 stretch. The new chain, which is the same kmc E11 as the old one, skips gears on the old cassette, despite trying to adjust it. On my first ride it even jumped into the spokes and took the derailleur with it, mangling it. So, changing the chain early prolonged the life of a 60chf cassette but it cost me a 90chf derailleur.

I think for expensive stuff, better to change the chain, but in future I think I'll let the chain play out until it skips too much then change the whole drivetrain. I guess there's a higher risk of snapping the chain, but this is less likely to cause a crash on an ebike as there's less power from the rider going through the chain.

As an aside, I once broke my collarbone falling off my clockwork road bike when my chain snapped under a lot of power (I was young and fit in those days), throwing me off balance. I was lucky. If I'd fallen the other way on the next pedal stroke I would have fallen into traffic on a main road.

Completely agree with you. On my normal bike I get in 2 chains per cassette as others are recommending, however, on my eBike I share your experience. Changed the chain at 786miles before 0.75 stretch like a good boy, and had skipping, chain coming off and eventually at 930 miles this resulted in a catastrophic mech failure. My feeling is that there is too much torque for the new chains to bed in.
Next time, to hell with changing my chain early. I'm going to run it until it pops.
By the way, I've "upgraded" from 11 speed to 10 Shimano Zee. Hoping it might be a bit tougher, and 36T cog is plenty for me + I find the 46T on 11 speed used to spin out too easily, and I was tackling the steepest of climbs in 37T, so I figured why not save the 100g of unsprung mass, and a few quid!