I have had a 3×10 drivetrain since May and have been through 2 XT chains since then.

The first one snapped and I put it down to crap installation on my part (something I haven’t ruled out for the second).

It snapped whilst riding, I fixed it and it snapped again and again. After losing so many links the chain was then too small so I had to get another.

It has lasted till now (about 20 rides) but last night snapped after a steep climb. Fix, snap, fix, snap, fix, snap.

I made the stupid mistake of big ring little cog before which probably resulted in the weakness for the first snap but I have never had issues of an many breaks on the same ride before.

What am I doing wrong? Is there a technique to reattaching the chain that is different to a nine speed? I have noticed that when I push the pin out of a link to then re attach the chain a small metal washer is left on the end of the chain tool after extraction. Is this normal or do I need a new chain tool?

Is there a special technique to fixing 10 speed chains or are they just inherently weaker than 9 speeds due to their reduced width?

You should use a ‘missing link’, even 9speed (and a lot of 8 speed) wasn’t supposed to be re-joined by the old ‘push the pin out and back in again’ method. It still works as a bodge to get you home if done very carefully, but IME it always fails again soon after.

The tolerances and manufacturing on new chains get better with each generation of chains, the Shimano 10s MTB chains should considerably outlive their 9s equivelants if you split and join them correctly.

It’s possible to use 9s links on 10s chains withotu any issues (they’ll pass through all the gaps) so that’s the cheepest way (often 99p for 2 pairs, rather than £3 for a single pair of 10 plates, and the 10s ones are often single use!)

The good news is if you still have the old chain, it’s probably still good to use, just stick some extra length in there from new chain and carry plenty of missing links untill (as the previous bodges will inevitably pull appart over time).

Great reply. Thanks thisisnotaspoon!

When you were joining the chain, were you re-using the pin you’d previously pushed out to split the chain in the first place?
I always though that Shimano chains had to be re-joined using an oversized pin that you pushed through and then snapped the guide part of the pin off. (Assuming you aren’t using split links).

Yeah that ring of metal on the chain tool is the rivet head. Once that goes then it will always come out. I know as ive just had a absolute nightmare with my chains(all self induced)

Did you use the oversize joining pins I mentioned? ^^^

I am guessing that unless the OP had a packet of joining pins in his bag hecwas reusing the pin already in the chain. And as others have already pointed out, this is not a good idea.

Yes re-using pin in chain, I wasn’t carrying spare oversized pins as Mr. Shimano would rather make a massive profit margin on selling tiny bits of metal instead of including some in packaging. Ok so this has been my problem. I guess it’s down to lbs to get some master links/joining pins. I marvel at how some bike mechanics have jobs. I’ve asked this in two different shops and they looked at me like I was a moron and told me to do it “como siempre” (as usual). The joys of Spanish customer service.