I've been a hobby mountain biker for a couple of years now. My bike is getting older and older (10+ years, still 26 inches) and I would like to do more maintenance jobs myself since it is not worth spending tons of money on it. I sadly don't keep track of my kilometres and are more of a weekend driver. Last chain replacement was last year, other parts of the driving train more than 4 years ago.

I would like to replace my drive train as I have difficulties shifting (rear) but I want to make sure that I only replace parts that really need replacement. Could you please give me your opinion on the state of these parts? Cleaning is on my list, too 😉

enter image description here I think this looks pretty OK?

enter image description here I feel that the outermost / biggest and middle ring could be replaced as they are not symmetrical any more and are starting to get this shark-teeth look.

Thanks a lot!

  • 1
    First thing to do is replace the shifter cable, a lot more likely to be the cause of poor shifting. It is almost foolish to replace a driver train and not do the shifter cable, so might as well start with the cheap one you should be doing anyway. If that does not help, then onto driver train. Also check derailleur for play and jockey wheels for wear (although XT jockey wheels tend to last forever).
    – mattnz
    Commented Mar 21, 2023 at 23:42
  • 1
    Start by checking if the derailleur is still aligned properly. Use the barrel adjusters to change alignment, and see if that improves anything. After that, replace shift cables and housing. I'm pretty sure that will help. And of course keeping the derailleur mud-free can often make a big difference :-)
    – Burki
    Commented Mar 22, 2023 at 11:01
  • Thanks for the advice! I'll check the cables first then 👍🏼 Commented Mar 22, 2023 at 11:45

2 Answers 2


I agree that it looks pretty ok for a 10-year old bike, but if it doesn't shift well anymore (even with the best derailleur alignment you can achieve) then this would certainly be a reason to replace the sprockets. Do replace all of them though, and of course the chain too.

Now – some people might claim that it makes more sense to just ride the bike until it doesn't work at all and in the meantime save your money for a new one with 1× drivetrain. ...With which I would strongly disagree: 3×8 with good quality components is perfectly nice, so if you like the bike otherwise I would definitely hold on to it. And then it also definitely makes sense to renew the drivetrain, despite the not insignificant cost of the replacement parts. Especially if you do it now and thus maximise the time youget to use it before perhaps something else breaks catastrophically on the bike.

(If you would actually like to switch to a bike with e.g. more slack steering geometry, then this is another story of course.)

  • Thanks for your answer! I am quite tall and I'm therefore thinking of switching to 27.5 or 29 inches - so maybe ride until it breaks isn't too bad of an idea after all. Commented Mar 22, 2023 at 11:41

To my eye, looks like the cassette is well worn, see another of teeth looking a little like shark fins. Same with at least the biggest front chain ring. Can't really get a good enough look at the other two from the photo but probably safe to assume also worn pretty well. Would also guess the jockey wheels on the rear mech is a little past their best.

As per the comments, would think the shifter cable and cable housing are probably due a replacement. You may want to look at when doing all this is the bottom bracket, may also need replaced or a the very least a little love.

So I would say for a start at least you're looking at

  • Chain Ring x3
  • Cassette
  • Chain
  • Shifter Cable

With the possibility of

  • Rear Mech Jockey wheels
  • Bottom Bracket

One more thing to consider when pricing this all up, although it's one-off purchases, there are some speciality tools that will be required.

Final comment, see from the pic looks like you've got a XT crank there, assuming everything is of the same level of componentry, you MAY find it a little harder to source components of similar level yourself.

My opinion, I would almost be more inclined to take it to LBS to get this done because of the age.

  • Thanks for you answer, very appreciated! I'll check which components are available and go from there 👍🏼 Commented Mar 22, 2023 at 11:44
  • Agreed. The smallest cassette cog and largest chain ring show the 'shark fin' shape very clearly, especially on the top-most teeth in the two pictures.
    – BrtH
    Commented Mar 23, 2023 at 0:03

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.