I am, obviously…been through two chains now in two months.

Not sure what the cause is but it has something to do with the frame, I think. 2 snapped chains (both brand new), and before they snapped they were jamming a bit. Is it an issue with the geometry of the bike?

I’ve read that Inbreds are inherently vulnerable to chainslap and that it’s essential to put a protector on your chainstay – but has anyone else had the problem of repeated chain failures?

Most important, is there anything I can do about it? (must be.)

is there evidence of chain suck on the chainstay (big chunks of paint missing)?

where are they snapping – where you put the joining pin in?

wrong sized chains for rear mech?

Is it getting chainsuck? – The chain getting stuck between frame and chainrings?

The frame wont be any more sensitive to chainslap than anything else – not that i can see anyway.

Sure your chain isn’t too short? Should be big to big (not through derallier (sp?)) plus one full link.

Can’t see how the frame can be causing chains to snap unless alignment is out (kept happing to a friends singlespeed as the eccentric bb wasn’t sitting in exactly the right spot).

Chainsuck on my 456 is not uncommon, but the chainstay point is news to me. I’ve had 7 of the things over the years and only snapped 2 chains, so I don’t think it’s an inherent problem.

Definitely chainsuck – big gouge in my chainstay despite having a protector in place – right by the chainring teeth – the location made me wonder if the gouge actually came from the chainring somehow rather than the teeth (surely not) – anyway, does that indicate the cause of the chain snapping is my chainring, or even that my frame is the cause?

I’m sure I read that Inbreds in particular suffer from terrible chainsuck.

Think the rear mech could be causing it then? (thought I checked when I built it up…asked Planet X…but can’t quite remember…).

Thanks for your help – as you can see I don’t really understand the mechanics/engineering principles underlying my query – I’m just regurgitating some half-baked ideas I’ve heard. Interested to hear what the real deal is…

A friend of mine went through a whole bunch of chains on his inbred. must have been 6, 7 years ago? He never got to the bottom of exactly why, corresponded with Brant, had the alingment checked. One bike shop guy in the South West offered the explanation that “Some frames are just hexed.”

He does have a habit of breaking thigs, but he never had a problem with chains after he chopped the Inbred in for a Cove Stiffee.

Is yours baby blue?

Chainsuck can snap the chain (bend a few links, weaken them, snaps a short time later).

The frame can’t cause chainsuck (unless somehow you’ve hidden a huge magnet in the chainstay), but it can make it worse by having just enough clearence between the chainrings and the frame to jam it.

New chainrings, new chain and better lube can help solve it. The other solution is to go singlespeed.

Thanks. I hope I’m not being the Asky Man here…

1. Check chain alignment ie have you got the right number of spacers in the right place on the bottom bracket.

2. Check for chain ring damage. Even a slight bend or nick on the side of the ring can cause problems.

3. Don’t cross up the drive chain ie no large sprocket large chainring combos or vice versa.

I have/had two Inbreds and neither suffered from chainsuck.

IIRC isnt there an issue with extremely limited clearance between the chainstay and chainrings, which exacerbates the initial sucking?
Im sure I read that Brant suggested squashing the stay at that point to alleviate things?

IMHO frames don’t cause chainsuck… I presume what is generally meant is that some frames because of clearance issues are more of a nightmare than others to unjam the chain if CS occurs

Interesting technical discussion, although the outcome is the same irrespective of the precise cause – namely more dismounts to unstick chain on Inbreds than other frames.

Repeated chain snappages are a worry because the groupset is new – not sure what I can do to stop it happening again. Grease my chainstays?!

The chain had jammed a couple of times before this snapping incident – clearly the last jam weakened it to breaking point. Chain snapped around the powerlink.

Did the powerlink itself break?

Try a Shimano chain with a joining pin to see if it still happens?

Are particular chains more chainsuck susceptible?

The few chains I’ve broken followed chain suck + jamming incidents or a bad join when I didn’t use the right pin. A properly jammed chain can be twisted to some degree and that can loosen the plates enough for it to be a weak spot.

Not a fault of the bike really, more a series of minor issues with the broken chain being the end result.

I used to use a lower chain tensioner off the BB on my HT that had 1 or 2 rings. The tensioner stopped the chainsuck and slap until the point where it was chain/ring wear causing the suck.
Get a simple chain checker too, they can help spot a worn chain before it hooks the rings and starts sucking badly.

Shimano chain snapped then SRAM chain snapped

So a lower chain tensioner may be the answer

Thanks!

Powerlink itself broke