Help with Chain that keeps breaking.

Hi

I know this sounds like its me but...the only time I've ever broken a chain
on racing bikes is when they're worn out and when I broke the one on my moutain bike i thought the same as it was second hand and the chain looked like it had a good life. So onto chainreaction and bought an
XTR 9 speed to replace an SRAM PC-971 w/ Power Link that came
on the bike.

The new chain broke about 4 times in different places (no breaks at my join points) at different times, it is a 9 speed but its slightly wider than the SRAM so after a really good cleaning I went back to the SRAM and it seems ok for now but I don't trust it fully.


Now I know your thinking I'm shifting under massive torque but definitely not
your talking from flat to 10 degree inclines when the breaks occured. So suspend doubt in my abilities for a minute and tell me could it be the chainrings as the middle ring shows signs of wear.


What I have is

Cranks Shimano M762 XT custom for Specialized
CHAINRINGS 22S/32A/44A, 4 bolt 104/64mm
BOTTOM BRACKET Shimano M762 XT custom for Specialized
Cassette Shimano HG-50, 9-speed, 11-34t

If it is the chainrings maybe someone knows a very cheap source for an alloy
middle ring don't care about the brand as long as its light because posers like
me never wear them out.

Thanks


Billy

Deadly post !!
theres a load of reasons thats happening and i won't bore you with the details !!
get a Sram chain, a decent chainring and a XT or Sram rear cassette, replace everything at the same time, its a lottery mixing and matching nearly old or nearly new..
Shimano chains in my experience are made from butter or weakotanium..Mac the Knife or Al will put you straight on these..
However from my own experience , having tried the old replacing the chain periodically to extend the life of the Drivetrain only worked a couple of times over 20+ years.
I do ride my bike a considerable amount in awful conditions so I probably fall outside whats normal..
I just replace everything together once a year, its one really lovely feeling when you do !!
anybody who buys a secondhand chain is a mental case !!!

SRAM are definitely twice as good as Shimano when it comes to chains.

As far as replacing rings is concerned I have a complete set or XT rings for sale if your interested €40
(very light use - I moved onto a double ring setup)

Thanks very much for the good advise, just in case I'm way off about what i think proper wearing out is I might take some pics to get your opinion . As a whole cog swap out is going to hurt badly at the mo.

The whole bike is stripped down right now because its getting its shocks serviced so I'll be able to get some close up picks of the parts in question.

Many Thanks

Bill

Its almost impossible to rejoin a Shimano chain without using the special Shimano pins.. Just use powerlinks to fix any broken chain.. the only time I'd try join up a chain using the existing pins would be in an emergency 'on the trail' fix.. but as soon as I'm home I'd pop out the dodgy pin and re-connect with a power link..

Byrner is bang on with his answer..

Just let everything wear down til its practically falling off the bike then just replace the whole lot at the same time..

I'm a big Sram fan as anyone will tell you.. but over the years Sram chains have always had a reputation for being stronger and lasting longer than Shimano..

The most common chain breakage is usually up front.. on an upshift from granny to middle or middle to top.. any amount of load shifting at this point will literally just pull the chain apart..

Same goes for the back but to a lesser extent..

Other than that.. keep your drivetrain (chain / cassette / chainrings) clean.. this will prolong the life of the entire drivetrain..

Invest in a chain scrubber doodahd.. they are cheap and worth their weight in gold..

If your middle ring is worn then any new chain will skip all over the place and inevitably snap at some stage...

+1 with Byrner;

I now replace most things, annually - chain, cone thing, front sprocket things, derailleur wheels; then operating cables every 2nd year. I don't pay big money. My bike is probably 20Kg at this stage so saving 50g doesn't count.

However there is IMO a huge cost in being stranded with (or without) your mates 'cos your gear wore down and broke 'cos you didn't look after it. Self-induced unreliability is (in retrospect) plain thick.

On a related subject who are jockey wheels so expensive? The last time I looked they were a third the cost of a whole mech?!

Yeh ... and chain rings?