Broken the chain twice in one ride.

[Tom B]

I'd guess that your front mech isn't adjusted / indexed properly, and the chain has been rubbing against it, and not dropping cleanly on a down shift. It's possible that the quicklinks haven't been locked in properly as well. As for chains, I find Clarkes ten speed, or KMC 10 speeds to be most durable.

KMC x10-93 is what was fitted. Given we all seem to agree the chain is not at fault, and that is what I can obtain for sensible money.

There may be some milage in the FD adjustment issue. Prior to this ride I booked the bike in for it's 6 week tune up after noticing the shifting had become less precise.

It looks like a badly-made chain to me; what brand is it? I've got an almost unused KMC 10 speed chain with the spare links and a joining link that you can have for beer money if you fancy picking it up from north Blackburn.

Twas a KMC X10-93 And thank for the offer of the chain, I'll bear it in mind, hopefully I'll be picking one up tomorrow. But the offer is very much appreciated.

You are probably right. I didn't pay attention to the 200 mile bit, but just looked at the bit of inner ring I could see and it looked hooked forward to me.

Nevertheless, chainsuck has three contributing factors and a combination of any two can cause it.

1) Chainring size - smaller is worse
2) Smooth sticky mud or very gritty mud
3) Chainring wear.

Possible causes of chain suck other than wear>

• Chain too slack:

1. Too long - it should only be one link longer than the minimum needed to go round the big/big combination
2. Gear range is more than the amount the rear changer can handle
3. Rear changer gummed up and unable to take up slack

• Damage to little ring wear/burs/bent teeth preventing the chain releasing
• Damage to the next ring
  
• Poor gear adjustment
  
• Mud

Prevention

• Avoid the smaller sprockets when on the little ring
• Anti chain suck plates

Needs sorting as it can write off a frame due to damage to the chainstay and/or leave you stranded or removing the chainset to free the chain.

This starts to make a bit of sense. Whilst the bike has been used in some atrocious conditions it has only done 200miles since new. I have on a couple of occasions wondered about chain tension and lack of it. Given that it was under warranty and due its 6 week checkup I hadn't given it too much attention. I had perhaps naively assumed that the Halford's Bods had chosen the correct length. It is probably WAYYYYY too long, which will be handy in allowing me to take out the damaged section. Thinking about it the chain what probably on small - smallish at the time of the issues starting.

The teeth all look in good order, but I think I might strip the rings off after Halfords have 6 weeked it to be sure.

In fairness the ride was plenty muddy and wet, and at the point it first snapped I had just been through several large muddy gritty puddles. When i picked up the chain I was surprised how un oily it was given that I had applied lube prior to setting off and also how clean and free from grit it was. There was a combination of muds experienced from black peaty stuff, to sandy gritty slop to claggy clay patches. On the second occasion it was again on a rocky rubbly descent with running water. As mentioned I think I'll be using the TF2 Extreme Wet lube that I have in future and found too snotty for the commuter hybrid. The LBS who put the quick link in didnt re lube the chain (in fairness I didn't ask them)

I hadn't previously noticed but there appears precious little clearance between the big ring and the chainstay so much so that the chain and ring may not pass with the chain off the sprocket. That seems pretty poor design and will likely foil my plans for a slightly bigger ring in the fullness of time, but likely the frame was designed with the 1x set-up in mind as the rest of the range is 1x.

Thanks for your input. I wonder what Halfords will make of it when i take it in.

 

[Tom B]

Here is the chain large-large, it doesn't seem as bad as i thought, but I could still pinch out a few links, likely the damaged section :-)

Incidentally, I've measured the chain with my usual chain wear tool that I use on my 8 speed and it tests okay.

 

[Yellow Saddle]

Here is the chain large-large, it doesn't seem as bad as i thought, but I could still pinch out a few links, likely the damaged section :-)

Incidentally, I've measured the chain with my usual chain wear tool that I use on my 8 speed and it tests okay.

That chain is now the optimal length for large-large. Don't remove any links. You don't want the jockey cage to point forward to more than 45 degrees in that combination.

 

[Tom B]

That chain is now the optimal length for large-large. Don't remove any links. You don't want the jockey cage to point forward to more than 45 degrees in that combination.

Noted thanks. I'll have a look what it's like small to small.

 

[Yellow Saddle]

Noted thanks. I'll have a look what it's like small to small.

In that position it should not point backwards more than horizontal.