Sheared off mech

ram038

My rear mech has sheared off, don't know what caused it, there was a nasty grinding noise and I came to an abrupt halt. My question is as I have had the bike for less than a year would that be fixable under warranty. I can't think I caused it as I was not going very fast so I reckon maybe defective material. Next question is it is a boardman team with SRAM. i am thinking shortening the chain enough to make a single speed to get me home tonight. Do I need a special tool for taking the links out. I am not very "mechanically" minded sorry for the dumb question..

Tempestas

Is it the rear mech that has sheared off, or the mech hanger that the mech bolts into?

if so, they are designed to break and are a soft material, so a little knock can bend them enough so in your lowest gear they hit the spokes and snap off. The good thing is it usually saves the mech and the wheel, the bad thing is if you haven't got a spare....

ride_whenever

shortening the chain wont work, you wont have enough tension. Phone the cavalry to get home tonight, drop it into a bike shop tomorrow morning.

ram038

Tempestas wrote:

Is it the rear mech that has sheared off, or the mech hanger that the mech bolts into?

if so, they are designed to break and are a soft material, so a little knock can bend them enough so in your lowest gear they hit the spokes and snap off. The good thing is it usually saves the mech and the wheel, the bad thing is if you haven't got a spare....

the mech hanger got badly mangled when it snapped off, I'm not sure its saveable

Tempestas

So, bent hanger and mech went into the wheel? If so it's unlikely you can claim under the warranty

But, always worth a shot, I would take back to them anyway as they will probably be the only ones to have a hanger that fits.

ram038

what do i need to get the chain off so I can wheel the damn thing home?

ram038

The chain is a Shimano CN-5600, do I need a special tool to remove that.

Heckler1974

You'll need a chain breaker which is a thingy bob that pushes the pin out where the chain links breaking the chain.

http://www.chainreactioncycles.com/Models.aspx?ModelID=1625 kind of a thing.

Heckler1974

Oddly, the two bikes I've seen this on (one a road bike the other a mountain bike) were both from Halfords.

ram038

thanks for your help on this. I shall pickup a chaintool on the way home. where do you get the piece that attaches the mech to the hanger. If i order a new mech would that part come with it or do I buy that separately?

MrChuck

ram038 wrote:

thanks for your help on this. I shall pickup a chaintool on the way home. where do you get the piece that attaches the mech to the hanger. If i order a new mech would that part come with it or do I buy that separately?

The hanger is the bit that attaches to the frame, and then the mech attaches to that. If you get a new mech it won't come with a hanger- you'll need the right hanger to fit your frame.

ram038

MrChuck wrote:

ram038 wrote:

thanks for your help on this. I shall pickup a chaintool on the way home. where do you get the piece that attaches the mech to the hanger. If i order a new mech would that part come with it or do I buy that separately?

The hanger is the bit that attaches to the frame, and then the mech attaches to that. If you get a new mech it won't come with a hanger- you'll need the right hanger to fit your frame.

Another dumb question but how do you know what hanger fits your dropouts? I don't see any markings on it to identify it with. I have been on the boardman website but its not mentioned on there.

Heckler1974

ram038 wrote:

Another dumb question but how do you know what hanger fits your dropouts? I don't see any markings on it to identify it with. I have been on the boardman website but its not mentioned on there.

Tough question, best bet is to take the mech hanger into the bike shop and compare the ones they have in stock. They tend to be manufacturer specific but they can also be specific to a number of manufacturers. I have an old Carrera Banshee Mountain Bike that had a busted hanger and that it turned out was identical to a Kona MTB hanger (I believe that at the time Carreras and Konas were assembled/manufactured in the same Far East factory).

Not sure if Halfords will carry something like rear mech hangers but they may be able to order one in, but persoanlly I'd go into a local bike shop instead.

term1te

Quite a few years back I needed a new hanger, so went into my local Halfords (Maidenhead, now closed) and asked is they sold them. The guy went downstairs to see if they had any, he found one in the workshop which happend to be the right size/shape. As it had just been laying in a pile down there and wasn't a stocked item he let me have it for free. Which was nice.

Wappygixer

Mech hangers are designed to snap so as to save the frame.
I doubt it will be a warranty item as it would have happened earlier if it was a set up issue.
Most likely cause is it was bent caused by the bike falling over or you not shifting correctly under load which can put huge pressure on a drive chain.

Monty Dog

Defo no warranty claim, one of those classic "just riding along" incidents - most of the time this is due to crash damage, incorrect set-up / poor maintenance or road debris jamming the transmission