I usually run my chain and cassettes until they are knackered however, about November last year I got a new bike with a nice xt cassette and expander on it so thought I would try and make them last. I have read about people getting a few chains to a cassette by changing at. 75 on a chain checker. I have been regularly checking and as soon as it got to. 75 I have changed it. However it skips around all over on a ride today. Does it take a few miles to bed a new chain in or is it a case that the cassette is worn. Only done about 500 miles on it which doesn’t seem like a lot.

I had no problems with shifting before so tomorrow the old chains going back on and it’s getting run down.

I did much the same a couple of years ago.
I’m now completely back in the run them both until worn out camp . Change both together and maybe chain ring(s) every second or third chain / cassette.
Chain checkers, utter bollo*** in my current opinion.

Assuming you know how to adjust gears properly, then as above.. What cake said.
That’s why expensive cassettes make me baulk, they are very much consumable items in the same sense as chains and brake pads.

Yeah gears are fine, it’s the first time I’ve had an xt cassette with an expander so was trying to make them last. No problem before with anything before so the old chain is going back on and it’s all getting run down. Chain checkers are a load of rubbish!

Sometimes when a cassette gets worn it’ll only work with a worn chain. If you still have the old chain, stick it back on and see if it improves. Or buy a new cassette.

Run til it’s knackered and replace the lot is my current method.

For me it’s either that or change your chain every few weeks rotating 2 or 3 different chains. I did that for a while so I’d have one being cleaned/soaked in oil while other was usable/ in use. In the end I couldn’t be arsed if I’m honest as 9 speed cassettes and chains are mostly budget stuff these days and I never got round to the second 10 dpeed chain on the fs.

Have you checked for a stiff link. I had one where I put the pin in last time that caused a lot of jumping.

I change at .75 and get three chains to a cassette.

xt cassette and expander

Was that 500 miles with b knuckle screwed all the way in and little in the way of chain wrap?

@Dirtydog that’s what o was hoping for. The b screw will be most of the way in not sure what you mean by chain wrap though.

@Andy no I didn’t check for a stiff link but will do, it uses one of those split links (kmc) rather than a pin.

Exact same thing happened to me last year, back to just running them into the ground now! Changed it a bit before it got to 0.75 too.

n not sure what you mean by chain wrap though.

Basically how far round the sprocket the chain goes and therefore number of teeth/links engaged.

Assuming a 12 tooth sprocket for ease of explanation so I can match to a clock face for position.

For simplicity let’s say the first link touching the cog is at 1 o’clock as viewed along the rear axle from the drive side.

Call this tooth 1

At the bottom of the cassette with a non expander cog the last tooth that the chain engages with is say at 6’oclock. So the chain goes round from tooth 1 to tooth 6. (7teeth as you are going counterclockwise)

With an expander cog/mech pushed back on the b screw chain still enters at 1 o’clock but because the top jockey wheel is further back the last fully engaged link is now at say tooth 8. Now you only have 5 teeth of engagement.

So the same torque with the second scenario is going through 5/7 the number of teeth and therefore possibly causing a greater wear rate.

Basically how far round the sprocket the chain goes and therefore number of teeth/links engaged.

That only applies when the chain is new though. Even slight chain wear means that the last few teeth don’t bind anyway, and the more the chain wears the fewer teeth bind. I don’t measure wear, I just put a bit of tension on the chain, look down at the cassette and count how many teeth are binding. It’s very obvious. If it’s down to four or so, then I change the chain and the cassette shouldn’t need changing. It’s probably not cheaper overall, but it runs much more nicely. And your chainrings last forever, I’m still on original 2007 chainrings on all my bikes.

So you are right in that fewer teeth binding causes the cassette wear, but the tension screw won’t make a difference. The wear that destroys cassettes happens when the chain is stretched enough so that all your torque is going through one tooth at a time.

Thanks for that garage I understand you now. I’ll have a look later.

In your instance, does having the expander make the engagement with only the 5 teeth happen all the way along the cassette due to the b screw, whereas without an expander you would get engagement with the 7 teeth. (obviously it will ratio down the smaller they go)

It’s getting pretty technical is this!

Chain and cassette were perfectly fine. You’ve just put a new chain on a worn cassette and they won’t mesh together.

Either do what the industry is telling you and bin the perfectly good cassette, or stick the old chain back on and keep riding for another 1000 miles.

I don’t buy the cassette wears quicker with a “worn” chain. I have proof over two bikes testing both the Park Tools $hain $hecker method of binning chains frequently and the run to destruction. Running to destruction the cassette lasts just as long on one chain vs two or three, and in fact much longer I find as replacing chains you get to a point where new chains just won’t work but the cassette is still good, if worn a little. Loads of life left in it.

does having the expander make the engagement with only the 5 teeth happen all the way along the cassette due to the b screw, whereas without an expander you would get engagement with the 7 teeth. (obviously it will ratio down the smaller they go)

No. If only the first 5 teeth are binding, then it doesn’t matter how many other teeth there are.

I don’t buy the cassette wears quicker with a “worn” chain

It does – because the force of your pedalling is going through fewer teeth, hence the pressure on each one is greater. See my post.

I think the park tools gague doesn’t catch it early enough though. I once had a bike that came with a £200 titanium cassette. I wanted to preserve this as long as possible, and got almost two years out of it, so probably 6k miles, it was my only bike. I change chains early – this was back in the day when they were £6 though.

In my opinion, when a new chain skips, then the cassette is worn out *by definition*. Others definitions of worn out may vary.

Running to destruction

What do you mean by destruction?

Park Tools changed their checker at one point to indicate earlier. Was 0.75 and 1, then was 0.5 and 0.75.

It does – because the force of your pedalling is going through fewer teeth, hence the pressure on each one is greater. See my post.

Theory is one thing, proof is another. See my post 😉

Personally I think even if there is more wear, it’s not enough to justify binning chains every month or two. Sure you can change them even more frequently, but still rarely you’ll get past three chains and you’ve spent the equivalent on a new XT cassette on chains.

One chain, one cassette, 2000 miles I’ve done, thereabouts. If I change the chain a lot, I’m binning that cassette at 500, maybe 1000 max. Waste, especially when it’s not skipping or has any shifting problems.

p.s. I know the audience varies here, so let me qualify my experience by saying this is off road use, mountain bike, in every kind of crud possible. Road, I can’t comment on.

Another one here for running the chain and cassette into the ground. Tried swapping chains by 0.75 but the still skip. Any earlier and your swapping the chain out pretty quick (depending on hours ridden and conditions)Not sure the economics stack up considering a chain is only half the price of an XT cassette. If you have an expensive cassette then maybe it would be worthwhile.

I used to be in the ‘one chain, one cassette, run them into the ground’ camp, but the last couple of years I’ve switched to having two chains on rotation (about every three months/when I remember).

How it used to go was- new stuff in march, runs fine through the summer and autumn, starts to get a bit grotty towards christmas then a pretty steady wearing out with the last month or so to march being a fight to keep it working properly until the dry weather comes around.

In comparison, at the moment I’ve binned the first chain because I left it on too long over the winter and I’d probably get 2-3 months out of this one if really run into the ground. Maybe more if it’s dry.

It’s the swapping the chains that means it all wears together that seems to help for me. The only annoying thing is that I now have to decide between replacing prematurely to keep the annual cycle running or stringing it out.

Theory is one thing, proof is another. See my post

Your post didn’t make a lot of sense. I don’t know what ‘run to destruction’ means.

I preserved a cassette over about 5k miles and almost two years, by changing soon enough. Which is BEFORE the Park tool will tell you.

As I said – it’s probably not more economical, but I think it’s nicer. Having said that, it does save chainrings, and they aren’t cheap.

it does save chainrings, and they aren’t cheap.

They are dirt cheap now, partly by only needing one but also there’s loads by the likes of superstar etc.

I’m with molgrips on this. I’m not sure exactly what the Park chain checker relates to, but I change mine when it’s “stretched” by 0.5% (ie 12 double links now measure 12 1/16″ rather than the original 12″) as measured using a ruler – presumably that is 0.5 on the gauge?. Which is early enough to avoid the need to change the cassette or chainrings. A lot of people seem to be ignoring chainring wear in their calculations.

Though there’s another issue. Chains come with a hardened outer coating on the links. By 0.5% wear this has worn through and you’re onto the softer metal underneath. Combined with other factors, some of which have already been mentioned, as a chain gets worn the wear accelerates, so you won’t get anywhere near twice the life running to 1% compared with changing at 0.5%.

Maybe if you’re happy running with a very worn drivetrain it makes sense to run a chain into the ground, but things just don’t work as well – for a start the shifting will suffer, as that relies on lateral stiffness in the chain which is lost as the chain wears and becomes sloppy.

Good point aracer. I don’t measure chains like I said, I count engaged teeth. And wear does seem to accelerate dramatically near the end – so I check, think it’s ok for one more ride, then it’s clearly not and the cassette’s gone.

They are dirt cheap now, partly by only needing one

All my bikes need three. Plus two of them have XTR chainsets (from 2007) which are the first ones to have the carbon/ti middle ring. At £150 each I’d like to keep them 🙂

Maybe if you’re happy running with a very worn drivetrain it makes sense to run a chain into the ground, but things just don’t work as well – for a start the shifting will suffer, as that relies on lateral stiffness in the chain which is lost as the chain wears and becomes sloppy.

Also, I’m sure your riding mates will be delighted when it all goes tits up, miles from anywhere, due to your complete lack of maintenance. 😆

With 9 spd, my approach was “run 3 chains in rotation; fit the shortest; run the lot into the ground”
All components in the drivetrain were steel and it worked fine.

With the advent of 1×10 and an expander, the drivetrain now includes softer alloy components (expander and narrow/wide chainring), all are still relatively cheap though, so the same approach still kind of works, but the softer components (unsurprisingly) seem to govern the overall longevity of the “set”. It’s now typically two chains in rotation and throw the lot away when the chainring starts dropping the chain (wear effect on width of tooth? – a third chain wouldn’t help here).

Now I’ve got a bike with an 11spd X01 cassette, I’m definitely going to change chains religiously at 0.5 using a chainchecker. The price of the cassette is now the primary consideration. I want to ensure it lasts as long as possible.

I am pretty religious about changing just before .75 and it’s meant I’ve lost count of the number of chains my XTR cassette has had.

Last month I checked my commuter/trainer and it was at .75 or a tad over. Changed chain – SLX cassette skipped. Junked cassette as I’m precious about the chainrings (XTR for Stages – cheaper than buying a new powermeter)

I did have similar with a Campag cassette that wore into the chain after 20miles or so.

I’m happy to change my chain just before .75, save a bit on rings and have the extra reliablility. It normaly works for me. I suppose it might be more expensive but MTB is my only vice and I really don’t care.

The price of the cassette is now the primary consideration

Yeah – I idly looked into switching to 1x and was quite shocked at the cost of cassettes.

I put a new chain on at 0.5, but keep the old chain and stick it back on when the 2nd gets to about 0.75 then run the whole lot until it doesn’t work properly any more. Currently my mtb is on 4500km using the same cassette, range extender and n/w ring. The extender looks terrible but it all still works fine.

olgrips – Member
I don’t know what ‘run to destruction’ means.

It’s just a term a lot of people use. Doesn’t actually mean it disintegrates, although it might. To me, basically when the cassette is so worn everything is getting pointy, chain is skipping like crazy and nothing will save it.

aracer – Member
but things just don’t work as well – for a start the shifting will suffer, as that relies on lateral stiffness in the chain which is lost as the chain wears and becomes sloppy.

I never get shifting issues from a worn chain or cassette. It’s one day running smooth and next skipping and dead. Takes a long time though.

5k however – as I say, I’ve done the early chain replace, even plenty before 0.75, but three chains and it’s no go with the new one. Max 2k.

Very much depends on your riding though in my opinion. One person’s 5k is different to another’s, both in style and conditions. Add to that the maintenance aspect such as cleaning or lack of, oil used etc.

Anyway, I can appreciate chucking chains at a £200 cassette. I wouldn’t buy one myself as it gains me nothing. £30 XT does the job for me. I realise other people do see advantages though.

Well my experience suggests cassettes can live longer than you suggest.

FWIW I’ve always jetwashed chains completely clean and grit free.

And the £200 cassette came on a bike, I’d never buy one. Ok, so maybe when I specced my bling XC bike with insurance money…… 😉