3

I have a racing bike that is riding very smoothly without problems. Recently I bought a few SRAM chains on sale with the idea of rotating them a few times under the same crankset before they get too worn. However, when I was replacing the chain I noticed it was over 1% elongated.
My question is, since the old chain is still very smooth, should I keep using the bike as it is with the old chain, and wait until I need to replace the whole set? Would it be better to use the new chain for a while then rotate back with the old chain?
I know the best thing to do here is to change the whole crankset together with the chain, but since the bike is still very smooth I don't wanna invest the time/money to do that just yet.
I have 2 front gears and 6 rear gears.

2 Answers 2

4

It is hard to judge from outside because we can't assess the overall age and wear of your drivetrain and the costs involved. I think, eventually, you will come to the point where cassette/chainrings and chain need to be swapped together.

Continuing to run the elongated chain will increase wear on your other components, more than a new chain will. So it's more than likely that they are totally gone if you put more miles on your bike like that. It might be that the rest of the drivetrain isn't as badly worn as the chain, yet.

Just swapping the chain would be an intermediate step and might work for another iteration, that really depends on how worn the cogs and the chainring are already. I've had a similar thread going, swapped chains close to 1% without replacing other components and didn't have any problems like bad shifts or skipping. You'll probably still have faster chain wear than on a fully new assembly because the chain/teeth don't match up as perfectly but in my case (6/7/8-speed) chains were cheap and I still got relatively consistent life out of it (let's say 750 km in average on an all-season commuter).

Ideally, you'd do a full swap at some point, especially if the drivetrain doesn't run smooth anymore and/or you notice increased wear. That's indeed the most expensive scenario but worth considering when you ride the bike a lot. Replacing worn components and then staying on top of replacement (so way before 1% elongation) while having a good cleaning/lubrication routine gives you the best life out of your bike.

Personally, I'd try one of the new chains at least for a few miles and then decide.

7
  • How long have you been riding bikes? I don't remember 8-speed chains being this bad when they were mid-tier and 9-speed high end.
    – ojs
    Mar 18 at 12:03
  • Well, a decade or so, but I'm referring to my experiences with 6/7/8-speed chains on my commuter over the last few years. From what I understand, the "standard" option in Shimano terms is the HG40 chain, there seems to be a HG71 version with e-bike rating. I assume, if you go to a shop with a bike like the OPs and ask for a matching chain, you would end up with these - and (based on my experience) I doubt that you'd get out 3000 km or more like on a 11/12-speed road chain. Of course there are other brands but these often cost 3x more than the "standard" design.
    – DoNuT
    Mar 18 at 12:13
  • @ojs I think a lot of that is covered here, already: bicycles.stackexchange.com/questions/88911/… - I think that also contains a link to ZFC illustrating how bad these older chains perform compared to current road chain, albeit being narrower and probably lighter.
    – DoNuT
    Mar 18 at 12:15
  • 1
    Ok, I understand you meant that the cheapest 8-speed chain at your LBS is pretty bad. But somehow you wrote that all 8-speed chains ever made were bad. They are different things.
    – ojs
    Mar 18 at 15:21
  • 1
    @ojs OK fair enough, it wasn't a balanced statement (to say the least) and doesn't add to the answer, so I removed that paragraph.
    – DoNuT
    Mar 18 at 15:36
3

Since the drive train is working for you, I would keep using it. However - what do you use the bike for? If it is gentle commuting and you have no problems so far, just clean everything and keep using it. It is just my feeling, and some experience with commuting over the years. For peace of mind, best wait and replace everything, but in practical terms, that is overkill, you will not be replacing everything every time the chain is worn

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.