So I bought one of those chain wear tools. I dropped it onto the chain and its very worn… Bought a new chain, measured it against the old chain and off I go for a spin. Chain slips in almost all gears under load…. Worn cassette I decide, new cassette and fitted off for a ride. Still my chain is slipping, and still under load. Under inspection at home I can see that its slipping under load in the middle ring, not so sure about the top ring and definitely not in the granny.

Here is a picture of my chain rings, are they worn or am I missing something… ( I feel I was forced to wash my bike prior to taking pictures)

another view

What are my options for replacing the rings. I realise I can just buy another m590 middle, but buying a new big ring brings the price close to a whole crankset…
I’m thinking about putting the old stuff back on an riding until destruction….

If you wear the chain beyond recommended replacement %, then you basically bugger up the cassette and rings. Don’t put old stuff back on though, just replace and keep an eye on the chain wear. Btw – have you been grinding rocks with your chainset!?

Can’t imagine you’ll need a new big ring or granny, your middle is worn because you spend most of your riding in it.

^ this. Had exactly the same situation last month. Changed chain and cassette. Started slipping under power. Changed middle chainring and all is now good.
Just make sure that you get the right chainring (9 or 10 or 11sp).

Btw – have you been grinding rocks with your chainset!?

Yea I was surprised how scuffed they were.

Looking at the rings the big ring looks more worn to me (shark tooth), given that I’ve no idea what I’m looking for ???

The difference between the new and old chainring looked minimal, but obviously was enough to cause skipping. For the sake of ~£25 it’s worth changing.

I’ve got two nearly new (less than 100km each) 32T XT chainrings if interested. email in profile

I’m not sure if it’s the best solution but I dont bother replacing the chain and just use the drivetrain until it starts slipping then replace the lot, I seem to get about 5000-6000 miles out of it (about a years worth of use) so I guess thats not bad.

I would be interested to know what mileage others get if you regularly replace yuour chain though?

I run the whole lot into the ground and change everything together which is usually around once a year on average. My mates on the other hand changes their chain every other month but still change cassette and chainring as often as I do if not more often, especially if they’ve left it late and the new chain skips.

I run everything way beyond the chain wear tool but it never skips a beat regardless of amount of wear. I know it’s time to change when the chain starts snapping. I’ve tried other ways but in my experience it’s extra faff and false economy.

New chainring time…or fit old chain and cassette and ride into ground.