When is it best time to replace bike chain to prevent any cassette damage?

[MontyVeda]

Ok on hack/pub bike, keeps things simple, but not on any bike you want a nice day ride on I fear.

I replaced my chain cassette and middle ring last year... can't remember how long they'd all been on. A good five or six years I guess. Makes a lot more sense to me than measuring for 'stretch' and replacing the chain every year or so. It's only toward the end of the cassette/rings life that things get clunky... up 'til then, everything wears out in unison and the chain fits the teeth perfectly well. Each to their own though.

 

[gbb]

I replaced my chain cassette and middle ring last year... can't remember how long they'd all been on. A good five or six years I guess. Makes a lot more sense to me than measuring for 'stretch' and replacing the chain every year or so. It's only toward the end of the cassette/rings life that things get clunky... up 'til then, everything wears out in unison and the chain fits the teeth perfectly well. Each to their own though.

I kinda get that. The only fly in the ointment is excess wear in a chain can increase the risk of a complete failurr..not what you want if you're any distance from home.
A former colleague used to do the same, just run everything till it stopped working. I suggested an earlier chain replacement would save in some money in the long term...his immediate reply ?....I replace the lot every 2 or 3 years, the cost is nothing compared to running a car or bus fares, I just do it all in one go and forget it. No problems then for ages. Worked for him running a moderately nice hybrid.

 

[MontyVeda]

I kinda get that. The only fly in the ointment is excess wear in a chain can increase the risk of a complete failurr..not what you want if you're any distance from home.
...

i always carry a chain tool

 

[Sharky]

I tend to replace my chains/sprockets and cassettes in March with the wiggle vouchers I get for my birthday in February. If I don't get enough vouchers, they last another 12 months.

 

[Ajax Bay]

Don't think the OP said how many speeds their bike was.

Cassette: Sunrace 8-speed 11-32t

Stalking the OP's other posts suggests 8 speed.

excess wear in a chain can increase the risk of a complete failurr.

Please explain the mechanism for such a failure. What part of the elongated chain do you think will break (or whatever) or how will the drivetrain otherwise "fail". This is a chain/cassette combo which has NOT started slipping, remember.

i always carry a chain tool

So do I, and the times I've had to use it is to sort other rider's chain failures. These chains have always been either newish ones where the joining has been flawed or after riders has mashed a change under power.

 

[Yellow Saddle]

One thing that I've always wondered about is how to tell if your cassette is due for replacement. Does anybody know?
Thanks.

It is more of a philosophical question than a mechanical one. Reason being, that a worn cassette cannot damage a new or "unworn" chain, so therefore it doesn't matter. Another way of treating the question philosophically is to say that a cassette is almost never worn, only one or two sprockets on the cassette are worn, but unfortunately that ruins the whole cassette.

Treated as a mechanical question, there is no way or instrument for measuring wear on a cassette. Although, a skilled eye can easily see a worn cassette by comparing the various sprockets and looking out for a discrepancy in cog root size. A worn sprocket presents with oblong roots whereas a new one with perfectly circular roots.

Edit: Unfortunately the eyeis not a go/no-go tool.

I have in the past posted photos here comparing worn and new sprockets. A clever search should find them, I'm not clever enough. Perhaps just lazy.

 

[12boy]

I wax my chains and chains, cogs and sprockets last for a long time except on my Brompton, due to wheel size. However, most sprockets are as cheap as a chain. Find the right chain size on sale and buy a dozen. Warm fuzzy feeling knowing you have a bunch of new chains just waiting to be used. Master links make them easy to take off and clean up.

 

[Yellow Saddle]

Agree with the snail,(most chains up to 0.75% wear, although I think 11sp it is recommended to change at 0.5%.) Far as i know single speed chains can go to 1.0% plus i change the cassette every 3rd chain

At 0.75% elongation, your chain has already damaged you cassette, no matter whether it is 1 speed or 12 speed. The best time to change for minimising cassette wear is at 0.5%.
You are correct that a singlespeed chain can be used up to 1% but that's not because it is stronger. That rule is only applicable for singlespeeed HALFLINK chains. On a standard chain, only every second link elongates through wear but on a halflink chain, every link wears equally and thus it elongates more - exactly double.

 

[Yellow Saddle]

I replaced my chain cassette and middle ring last year... can't remember how long they'd all been on. A good five or six years I guess. Makes a lot more sense to me than measuring for 'stretch' and replacing the chain every year or so. It's only toward the end of the cassette/rings life that things get clunky... up 'til then, everything wears out in unison and the chain fits the teeth perfectly well. Each to their own though.

Your argument is fine, but find another analogy for time. Chains don't care about months, years, seasons or eons. It's miles of use under X conditions.

 

[Ajax Bay]

This was the discussion in 2017: https://www.cyclechat.net/threads/when-to-replace-cassette.215443/
And this was useful (imo): https://www.cyclechat.net/threads/why-a-worn-cassette-cannot-damage-a-new-chain.255700/
No pictures though .

 

[Lauris]

On my current chain and cassette, I have done 1000 miles. I cycle regularly meaning I'd need to change both around 6 times per year.
Luckily I don't need to buy expensive components as my bike is 8 speed. Right now both chain and cassette cost together £30. £180 per year assuming Id need to change it 6 times per year every 1000 miles.
And if my bike was an 11 speed these costs would be much higher!

I am fairly new to cycling but these expenses are not very pleasant.

I would not mind replacing the chain by itself every 1000 miles.
But from all the comments I see, needing to replace both is just too expensive considering the costs.

I might need to reconsider cycling as a hobby

 

[MontyVeda]

...
I am fairly new to cycling but these expenses are not very pleasant.

...
I might need to reconsider cycling as a hobby

I don't like spending money either... which is why i eventually thought sod it, I'm just going to run the chain 'til it breaks. What's the worst that could happen?

 

[Lauris]

I don't like spending money n
... which is why i eventually thought sod it, I'm just going to run the chain 'til it breaks. What's the worst that could happen?

Will you not wear out the front rings as well then ?

 

[Yellow Saddle]

I don't like spending money either... which is why i eventually thought sod it, I'm just going to run the chain 'til it breaks. What's the worst that could happen?

A manhood-related injury?

Years ago when I was still in the trade, I got a phone call from a cyclist. He wanted to know if we stock bearing balls. I said yes, what size? He said, "small ones."
I said: "OK, where do these bearings go?" He said in his back wheel. I said, "Is it a Shimano wheel"? He said, "no, it is the back wheel."
I said, "OK, bring the bike in, but how do you know that it requires new bearing balls"?
He said "because it goes ZRRRRT."
I said "ZRRRRT"?
He said "yes, ZRRRRT"
I said "when does it go ZRRRRT"?
He said "when I cycle".
I said "OK, bring the bike in."
He said OK.
Five hours later he arrives, having cycled from godknowshwhere on his utility bike with backpedal brakes and a single-speed freewheel.
I said: "Hello, are you the guy with the bike that goes ZRRRT"?
He said "Yes."
I said: "Show me when it goes ZRRRRT".
He got on his bike and applied pressure to the crank. Sure enough the bike went ZRRRT before it even covered 25.4mm of distance. (Reference thread on Miles or Kilometers).
I said: "It sure does go ZRRRT. Your description is so much more accurate than all the 'funny noises' we often have to deal with."
I took a look. His rear sprocket had no teeth left, just a small, shallow sinoid wavelike indentation every here and there where there once were teeth.
It turned out he had cycled some 40kms to get to us. He sure knew how to "feather" a pedal.

 

[boydj]

On my current chain and cassette, I have done 1000 miles. I cycle regularly meaning I'd need to change both around 6 times per year.
Luckily I don't need to buy expensive components as my bike is 8 speed. Right now both chain and cassette cost together £30. £180 per year assuming Id need to change it 6 times per year every 1000 miles.
And if my bike was an 11 speed these costs would be much higher!

I am fairly new to cycling but these expenses are not very pleasant.

I would not mind replacing the chain by itself every 1000 miles.
But from all the comments I see, needing to replace both is just too expensive considering the costs.

I might need to reconsider cycling as a hobby

An 8-speed chain will last a lot longer than an 11-speed. Use a ruler or buy a chain-measuring tool and then change when the chain is worn. Just doing it by mileage does not take account of riding conditions and will lead to extra cost.