Can I just let the chain/cassette/big chainring all wear out together now and replace later?

[cougie uk]

I think they are either having you on or playing very cautiously.

Or youve been riding a filthy chain all year.

If it was me I'd replace the chain now and see how you go. Sometimes it takes a week or two to bed in. Keep the old chain and clean it whilst off the bike. If the new one is jumping you can always go back to the old one.

 

[Smokin Joe]

From many posts on the same subject over the years it seems to be the default diagnosis of certain bike shops that you need to replace the whole drive train every time you have a problem. As others have also said, the only time I have ever replaced a chainring was when I wanted to alter the gearing, and I've clocked mega miles on some of them.

 

[ColinJ]

Big rings DO wear out... Mine started plaaying up on my Garforth forum ride on Saturday. It went from being a bit noisy to VERY noisy in 100 miles. Mind you, it had been used on a couple of my bikes and done a good distance on them, then I put it on my singlespeed bike where it gets a lot of force put through it on climbs. I'd be surprised if it had done less than 10,000 miles.

 

[Tapper3279]

Thank you everyone for the replies! I've attached some photos below but will also try to answer some questions.

What about the 34 ring? You’ll need it up Talla

Its barely been used.. almost like I knew I was saving the 34 ring for this upcoming sportive Have you done it yourself?

Seems like an awfully short amount of time to trash the drivetrain. Do you ride a considerable number of miles per year and is it predominately off road?

I've only done about 1200 miles since I got the bike and that has included me changing the cassette and chain in October 2020 like I said. so it definitely seems a bit premature.

Might just be a case of offering a free safety check and telling people it needs stuff done that it doesn't to make a bit of money.
I've had it before with arnold shark...your windscreen wipers need replaced. We can do that today for £xx.

I don't think the Decathlon mechanic was doing that tbh. Seemed very honest. He also said he couldn't even get the parts because Decathlon would take too long to get the stock so he said if I brought the parts in he would do the labour for free, so seemed pretty genuine. He did show me using the chain checker that it was definitely stretched. But for the cassette and chainring, I've attached pics so people can judge. I really cant tell myself!

Or youve been riding a filthy chain all year.

I actually think its been the opposite. I just got into biking last year and done a lot of reading, and I quite religously degreased my chain and then lubed the chain back up. But I actually think this might have been my downfall in that was stripping the lube out each time but not sufficiently lubing back the chain!

 

[ColinJ]

Wow - that ring really IS worn... My noisy worn one is nowhere near that bad!

What have you done to the poor thing?

 

[battered]

That does look well used. If that's what happens when you clean the chain regularly, I'll carry on adding oil, wiping off the excess and letting the dirt get swept off on the jockey wheels. I've got chainrings that have done 10x that distance and still work.

 

[Milkfloat]

I concur, I don’t see how you can do that in 1200 miles, but for sure, new chainring required. I would get a chain checker and see if that needs doing too, if the chain is knackered then I would assume the cassette to be too seeing as you are on your second chain. It is difficult/impossible to tell if the cassette is past it’s best just by looking, for sure it is not completely screwed. If it is all knackered then you could do worse than run the whole lot into the ground and wait until the chain starts slipping. That can be a risky strategy as if it does that whilst you are out if the saddle putting the power down, you might injure some plums or worse.

 

[raggydoll]

Thanks for the photos.
Yeah, the chainring does look pointy and sharktoothed.

I'm shocked!

You can see the difference between a new one and yours:

Especially the teeth at 3 oclock position in your photo above.
Those ones are really pointy and sharky.

You said the chain was stretched too.
Cassettes are the hardest to tell if they are worn but if you are replacing the chain and the chainring, then as you mentioned in your first post, it would be best to replace the cassette too.

Then it's like starting from scratch and you can work on not trashing the new stuff in 12 months!

So now that we believe the bike mechanic ...back to your original question, if you are replacing all 3 anyway (chain, cassette and chainring) you do have the option of running it completely into the ground. The only other thing I can think that would be left to get damaged would be the jockey wheels in your rear mech from a stretched chain. Jockey wheels end up like ninja stars when they get worn.

Apart from that, would be the safety aspect.
If your chain is stretched and things are worn then things will start to skip under load which could be dangerous.

Probably best to replace sooner rather than later.

 

[the snail]

When you buy the new kit, get a tool to check the wear on the chain, or a steel rule. With 11speed, I think you're supposed to change the chain at 0.5% stretch. Once the chain wears beyond tolerance, wear on the cassette and chainrings increases significantly.

 

[raggydoll]

11 speeds and higher should be changed at 0.5%.
10 speed and under should be changed at 0.75%. Their bike is 9 speed so would be changing at 0.75%.

I use the park tool cc3.2 cos it shows you wear at 0.5% and 0.75% so covers all speeds.
Some chain checkers do 0.75% and 1% so you'd need a different one to check the 0.5% reading.

Even with 8 and 9 speeds, I check the 0.5% reading first. If it doesn't go in then of course it's no where near the 0.75%.

As soon as it starts to fall into the 0.5% I can check the 0.75% more regularly to know when it's time to change.

As soon as it starts to drop into 0.75% I change.

There are quite a few on the market though so have a look around.

As mentioned above you can also measure with a ruler (1 full link should measure 1 inch).
I always found it hard to measure though as chains flex and move and the measurement difference is so small that I find it easier to use the chain checker. To each their own though.

Video below explaining how the park tool one works (they have a few different ones and there are other makes available).

But they are pretty cheap and let you check yourself and change at the right time without needing to take it to a shop for servicing.


View: https://www.youtube.com/watch?v=SpJcm5mf8ug