Broken Stem??

markpotts147

I bought a new stem from Chain Reaction (very good service by the way). Was fitting it this morning and over tightened one of the screws. As a result SNAP! Half the screw is in the bin and half is stuck in the stem. Is this still safe to use or should I put my old one back on and pay £55 for another


IMG00273-20110326-1146 by mp147, on Flickr

5pudgun

Can you not remove the broken bolt and replace it. There are tools available to do this

pingpong

Why would you need to buy another stem? Just take the snapped screw out and replace......Torque Wrench comes to mind, oh I would not go out on the bike with only 3 screws holding the handle bars in place, I would not feel comfortable about it, but then that's just me

andyrr

Don't use the stem in it's current state - I realised I'd ridden for a short time with 3 out of 4 bolts in place (don't know where the 4th one went) and the face plate fractured. Was a Deda Newton. Too much stress will be placed on the remaining bolts and the fact that the stem/bar interface is not as designed with nice equal forces all across it.

Stewie Griffin

It's because you put the front bit on upside-down.

sungod

i've done the same - at which point i realised my torque wrench had gone gaga, luckily in warranty

to remove the piece of bolt, take off the faceplate

if there's enough sticking out, slot it with a hacksaw and use a screwdriver, or maybe use pliers to turn it

otherwise, drill a hole in the centre of the bolt, then either use a screw extractor to remove it, or put a small bolt into the hole and use that to drive the bolt out through the other side of the stem

c0ugars

You dont need to buy a new stem, just remove half the screw, i would do this by drilling it out.

rake

torque wrenches are made for people like you (no maintenance skills). i dredd to think how tight it was to snap the bolt.

Monty Dog

Trying to drill out the screw might be tricky unless you have access to a pillar drill. It is not under tension and you may be able to unscrew it using a scribe or fine-pointed tool to try and turn it. You don't need a full-blow torque wrench, just a Ritchey Torqkey for £12 which is preset to the right torque for bars and stems.

ajb72

rake wrote:

torque wrenches are made for people like you (no maintenance skills). i dredd to think how tight it was to snap the bolt.

Crikey, that's a but harsh isn't it?! I've been building and maintaining bikes for 10 years and I use a torque wrench. Some of these tightening recommendations are pretty low, I defy you to tell the difference between 5, 6 and 8 nm of torque with an allen key and your bare hands only.

That aside, it must indeed have been severely over tightened.

brin

Stewie Griffin wrote:

It's because you put the front bit on upside-down.

rake

ajb72 wrote:

rake wrote:

torque wrenches are made for people like you (no maintenance skills). i dredd to think how tight it was to snap the bolt.

Crikey, that's a but harsh isn't it?! I've been building and maintaining bikes for 10 years and I use a torque wrench. Some of these tightening recommendations are pretty low, I defy you to tell the difference between 5, 6 and 8 nm of torque with an allen key and your bare hands only.

That aside, it must indeed have been severely over tightened.

ok, i retract. carry on breaking bolts

stevec205gti

Another thing you can try if it's recessed in the hole is a smaller flat ended piece of metal/plastic and some glue - don't use too much as you don't want it to spread and run into the thread. I'd view drilling it out as a last resort

sungod

if you can't get it out with persuasion, use the screw extractor

they only cost 2-3 quid, and once you've got one sod's law should help protect you from breaking any more bolts :-)

i've done it on a stem bolt with a handheld powerdrill

you need a 2mm drill bit, followed by a no. 1 screw extractor, it's a 5 minute job

just make sure you get the drill bit centered and start slowly and along the axis of the bolt, you need to get the hole about 7-8mm deep

then just put the extractor in and turn anticlockwise, it'll bite into the bolt and unscrew it