Help!

[NickTB]

Took the CAADX out today for a real test of its off-road capabilities... it coped really well until we hit a farmers field and I ended up bogged down and face first in a pile,of horse shoot anyway, once back on the road I scooted through a few puddles to clean off most of the crud when I noticed a pinging sound and the chain came off. Put it back on and started off and the derailleur flew into the spokes. It’s sheared off the frame. please see pics for reference. To add insult to injury my new brakes and rotors were delivered at the same time as I finished my 3 mile trudge home...

First pic to give you an idea of the terrain we were in when it happened
Does anyone know if this repairable?

 

[rogerzilla]

You need a new hanger. They are designed to be sacrificial. You may need a rear mech but try just the hanger first.

 

[vickster]

I did similar not that long ago (not in a field but thanks to discarded wire in the road that wrapped itself around hub and spokes). I had to have a new mech and chain as it was wrecked...luckily it wasn't the hanger as it's part of the steel frame and would have been far harder to fix!!

 

[NickTB]

You need a new hanger. They are designed to be sacrificial. You may need a rear mech but try just the hanger first.

Ah cool. So the hanger just bolts through the frame? on a more positive I’m liking Muc off

 

[rogerzilla]

Have you had a look to see where it bolts on and removed any remains to check the frame is unaffected?

 

[NickTB]

Have you had a look to see where it bolts on and removed any remains to check the frame is unaffected?

Just about to do that now

 

[NickTB]

Frame is fine, although one of the bolts has sheared and now I can’t get to the head to unscrew it. Otherwise the frame looks fine

 

[rogerzilla]

https://derailleurhangerstore.co.uk/collections/cannondale-derailleur-hangers

 

[rogerzilla]

The screw shouldn't be tight now, if the head has sheared off. Can you get to either end of it with molegrips? Drilling it out is a last resort.

 

[NickTB]

The screw shouldn't be tight now, if the head has sheared off. Can you get to either end of it with molegrips? Drilling it out is a last resort.

No, the head is recessed and the sheared part is flush with the frame

 

[rogerzilla]

What material is the frame part with the screw in it? Aluminium?

 

[NickTB]

What material is the frame part with the screw in it? Aluminium?

Aluminium, yes. This is how it looks. It appears that someone Overtightened it previously

 

[rogerzilla]

The screw is probably steel - can you check it with a magnet? Even most stainless steels will stick to a strong magnet. Drilling it out is definitely high-risk if the screw is harder than the frame. If it is steel, heating the dropout with a heat gun or hairdryer will help loosen its grip as the frame hole will expand by more than the screw, but you still need to get hold of it somehow. I'm assuming it's M4 or something equally tiny? It may be a job for a professional.

 

[wafter]

Man, that looks nasty... the screw will be steel and note how it appears to be bent within / deformed the hole, so IMO that's going to be a swine to get out.

Usually I'd suggest drillng and a stud extractor, but given the state of the screw this is only likely to cause more damage. You could try drilling out the bulk of it then using a fine punch and pick to try and get the rest out of the frame.. or maybe drill the bent end only and attempt to take out most of it with a dremel type tool or deform the bent bit enough to allow the screw to be wound out (toward the bent end) without causing too much more damage to the frame.

Note also that given the state of the hole you may have a job getting a replacement screw to tighten sufficiently without stripping the remaining threads.

Possible I guess that it could be drilled out oversize and a thread insert used, assuming the deformation of the hole isn't outside the diameter of the hole required for the insert.

On a more positive note I love the air of hapless toil and determination in the first pic

 

[NickTB]

Man, that looks nasty... the screw will be steel and note how it appears to be bent within / deformed the hole, so IMO that's going to be a swine to get out.

Usually I'd suggest drillng and a stud extractor, but given the state of the screw this is only likely to cause more damage. You could try drilling out the bulk of it then using a fine punch and pick to try and get the rest out of the frame.. or maybe drill the bent end only and attempt to take out most of it with a dremel type tool or deform the bent bit enough to allow the screw to be wound out (toward the bent end) without causing too much more damage to the frame.

Note also that given the state of the hole you may have a job getting a replacement screw to tighten sufficiently without stripping the remaining threads.

Possible I guess that it could be drilled out oversize and a thread insert used, assuming the deformation of the hole isn't outside the diameter of the hole required for the insert.

On a more positive note I love the air of hapless toil and determination in the first pic

This gives a better idea of what I’m up against


imageupload

and yes, that pic was halfway through the field!