XTR M952 chainring rot

[bikeworkshop]

Not sure the rings have meaningful part numbers stamped on although marked 9 and 10 speed - mostly 32t
These guys have the plastic shifting ramps - perhaps all alloy was replaced?
Here is a part no:

 

[ishaw]

It was only the chainring bolts holding the middle ring together

View attachment 853573

Scary.

Here's a set which seems to have a decent middle and outer, m950 not m952 but pretty much the same. Inner seems to be going the way of your middle though.

Shimano XTR M952 M950 Chainrings 46-34-24 | eBay

<p>I believe these are for an XTR crankset</p><br /><p>Please review all photos. </p><br /><p>The single chainring on its own appears very worn </p><br /><p>The granny ring has some of the coating peeling on the inner side. Not as noticeable on the drive side. </p><br /><p>You’re purchasing what...

www.ebay.co.uk

 

[ishaw]

View attachment 853624
Not sure the rings have meaningful part numbers stamped on although marked 9 and 10 speed - mostly 32tView attachment 853626
These guys have the plastic shifting ramps - perhaps all alloy was replaced?
Here is a part no:View attachment 853632

They are later gen xt (m770) but do fit m970 xtr I believe.

Never tried them as alternatives to m952 rings, do they fit? Could be interesting if they do.

 

[bikeworkshop]

They are later gen xt (m770) but do fit m970 xtr I believe.

Never tried them as alternatives to m952 rings, do they fit? Could be interesting if they do.

We used to see a lot of m950 series chainsets - i don't ever recall seeing a replacement ramped middle ring all alloy, so perhaps shimano changed the design early?
Techdocs ought to give a compatibility rating, although it's not always reliable.
There's an xtr 950 spider in the same drawer, I'll offer it up and post back

 

[minor_LEGEND]

Maybe it's not played well with a particular lube of some sort. Like a chemical reaction has taken place.

 

[bikeworkshop]

As far as I know, they aren't bonded.

If you have a load nocking around then I'd be up for one or two as I have a few xtr m95x chainsets on bikes I'm not looking to part with ever, but would like to ride them (more) and keep them running with a stash of spares.

Sadly they don't fit. 112
I've got a couple of spiders, one looks double
... one looks single

 

[retrobate]

Aye - inner & middle ring have gone really granular. Outer ring is fine bar the minor tarnish marks. What surprised me was the middle ring splitting - looks to be 2 parts bonded together that have now started separating.

Thats exfoliation corrosion. The corrosion migrates along the materials grain boundries its particularlly common in the higher strength alloys 2024, 7075 etc. I have seen bits of aircraft structure that looks like a well thumbed paperback

 

[ishaw]

View attachment 856006Sadly they don't fit. 112
I've got a couple of spiders, one looks double
... one looks single

View attachment 856017

The one that looks like a double is a standard outer ring spider with the ring lopped off, making it a double.

Do you have any pics of the triple?

 

[rwm1962]

Thats exfoliation corrosion. The corrosion migrates along the materials grain boundries its particularlly common in the higher strength alloys 2024, 7075 etc. I have seen bits of aircraft structure that looks like a well thumbed paperback

Is there anything that can be done to prevent or slow it down?

 

[bikeworkshop]

The one that looks like a double is a standard outer ring spider with the ring lopped off, making it a double.

Do you have any pics of the triple?

Of course - the outer ring was integral to the spider so effectively there's only 2 rings attached!
The other spider looks like single, ill look in the box downstairs as if I can find a triple