how long does a chainset last?

turbo_hamster Posts: 122
edited December 2008 in Road beginners
I have had my road bike for 4 and a half years and by coincidence, have done about 4 and a half thousand miles (according to the computer).

I have been planning to replace cassette, chain and chainrings after the winter, but things seems a bit rough and I have had a quick look and notice at least one of the cassette sprockets seems to have a damaged tooth.

Was in a bike shop for something else and asked about replacement costs, just to get an idea of what it is all going to set me back. The assistant asked me how old the bike was and I told him about the 4.5 years/thousand miles. He seemed a bit quiet then and I just wondered - do I look an idiot because the bike should be trashed by now? Or do I look an idiot because no way should the bike be trashed yet?

I am not especially knowledgable about bike maintenance and I am female. In addition, I was once lied to, big-time, by a bike shop about an expensive replacement part they said I needed. Now I am left feeling all paranoid, so I would really, really appreciate an insight into how worn-out my chainset can be expected to be. I am on my second chain (2000 miles old now, but according to my chain checking tool, not worn out). Oh yes, and I do regularly clean and lubricate the bike.


  • bill57
    bill57 Posts: 454
    Not sure about Campagnolo, as I only use Shimano, but the teeth on a modern cassette are all sorts of shapes, with ramps to allow smooth indexing. I would expect them to wear, obviously, but they're pretty tough and I would have thought hard to damage. Got a photo?
  • Infamous
    Infamous Posts: 1,130
    Put a new chain and cassette on, if the new chain starts to skip on the front chainring, change that too.
  • It depends what conditions you've been riding in but if it's mostly fair weather, replacing the chain and cassette should be adequate. Chainrings last quite a while so unless you damage a tooth you should probably get another few thousand miles out of them. Some cassettes have missing teeth intentionally (SRAM for example) but if you've sheared one off make sure there's nothing bent outside the line of the damaged cog that is going to damage your chain and make irritating noises. A pair of pliers and/or metal file will do the job.

    Bike shops very frequently tell people to replace both the chain and cassette because you can get skipping with a new chain on an old cassette and so it saves their mechanic time and trouble and - if you take their advice - doubles their revenue (at least depending on the cassette). If you maintain well as you say you should get through several chains before the cassette is worn out, broken teeth or accidents excepted.

    Ignore the bike shop assistant's look. Sounds like you're doing all the right things!
  • guv001
    guv001 Posts: 688
    I've done around 12,000 miles on my chain, cassette, I just put it in for service and I stayed next to the mechanic while he tested the chain for wear and he said it was fine. So I think no definate answer can be given without someone actually looking at the bike.
  • balthazar
    balthazar Posts: 1,565
    guv001 wrote:
    I've done around 12,000 miles on my chain, cassette, I just put it in for service and I stayed next to the mechanic while he tested the chain for wear and he said it was fine. So I think no definate answer can be given without someone actually looking at the bike.

    You don't need a mechanic for at least some of that: if you have a ruler. or tape measure, at home, you can check chain wear yourself, by measuring a foot of chain, through the centre of its links. 12 links of a new chain will measure 12 inches. Chains that, through wear, have lengthened by a half percent, should be replaced: that corresponds to a a sixteenth of an inch over 12 inches, or 306.5 mm. I'm doubtful that a chain lasted 12,000 miles without wearing tht much, but I'd be delighted to be wrong.
  • cougie
    cougie Posts: 22,512
    Chainsets should last lots more than 4000 miles. Any club rider would easily put that in in a years riding. Its only 80 miles a week.

    Do the teeth look hooked ? Doubt they would after just those miles. And prob ignore the wear on the sprocket - some teeth are smaller than others to help shift up.
  • A lot is dependant on your maintenance regime and riding conditions.If you clean and relube your chain regularly,and use a chain checker ,as you appear to be doing you can make the whole drivetrain,cassette,chain and rings last a long time.

    On my mtb I manage to wear the drivetrain out in 1000 miles or so despite thorough and regular maintenace,whilst the road bike at similar mileage is barely worn.

    If ridden through the winter I`d reckon 4500 miles is pretty good going but my experience is based ,more on mtb use and with aluminum Shimano rings which are soft as butter and wear rapidly.

    I normally replace chains when they are between 0.75 and 1 on a Park tool checker,so as to not cause premature wear to chain rings and cassette.

    The chain is the cheapest part so makes sense to change it regularly particularly as a new one is only about a tenner.

    Once you have worn rings and cassette though it is best to replace the whole lot.Always check out the cost of a new chainset v rings though.(Also factor in the cost of a new bottom bracket,if you need one)You can get some pretty good chainsets for as little as £50,these days and it often works out cheaper to buy the whole chainset rather than rings/bottom bracket.

    Some good deals to be had on chainsets at Parkers at the moment.

    The link below might help you decide if your current set up is worn;
    2006 Giant XTC
    2010 Giant Defy Advanced
    2016 Boardman Pro 29er
    2016 Pinnacle Lithium 4
    2017 Canondale Supersix Evo
  • FWIW, I've just replaced the chainset on my commuter after a touch over 4000 miles, though that bike does get used all year round and doesn't always get the maintenance that perhaps it should. It was actually only one chain ring that needed replacing (as I was getting horrid chain suck when I put on a new chain) but the bottom bracket was stuffed too, so it was just as cheap to get a whole new chainset...


  • cougie
    cougie Posts: 22,512
    I guess it would depend on the part as well. I find Dura Ace last forever. Cheaper parts wont.
  • Many thanks for all this useful information. It has helped me plenty. Also, I have (a) worked out why things felt "wrong" and (b) sat for half an hour inspecting each sprocket tooth individually with a torch.

    Conclusion is that my chain was splitting itself and I was very lucky not to get stranded miles from home yesterday. No wonder things felt "wrong" as one outer plate of the chain was no longer held by the rivet. Fixed now.

    The other conclusion is that the wear I can see on the sprockets and chainrings is probably not enough to warrant a replacement. I didn't realise that the chainrings lasted longer. Thank goodness, as I have been pricing them and it looks like about £80 for a new set of three. And the guy in the bike shop was no doubt thinking privately "she doesn't need new kit, but I will sell it to her if she says she wants it". Bike Radar Forum saves me money!

    Cougie, thanks for pointing out that the sprocket teeth are not all the same length. I have looked very carefully and feel I was over-reacting before, i.e. panicking.

    So now I am confident to carry on with sprocket and chainrings. I think I will follow the advice above and keep an eye on the chain wear then get a new chain to help protect sprockets and chainrings.

    I was intending to buy an "alternative" cassette to use for a tough sportive next year. I need some help getting up all the hills... so it looks like the chainrings can stay, but I will look at a chain/cassette combination with more teeth. Yes, I will check I have capacity on my rear mech!

    So, one last query. Assuming the chainrings are still OK, is it sensible to get a lower-geared cassette plus dedicated chain for riding steep terrain, keeping the original not-too-badly-worn cassette and chain to get more use next winter? Will the chainrings be ok with this system?

    Thanks again for the really useful feedback.
  • markos1963
    markos1963 Posts: 3,724
    The drive train on my Raleigh Record is over 20 years old! and is still going strong. Must admit its not the lightest but is certainly tough.