adjusted the angle of my handlebar and heard a 'snap'??

[hero of valour]

i adjusted the angle of my handlebars by loosening the 4 screws which tighten and hold the handle bars in place and as I was tightening one of the screws i heard a 'snap' which was a similar sound to when i snapped by seat collar the other day (yes, tightening it too much again). there's no sign of anything being damaged apart from the fact the said screw just turns now and cant get any grip to tighten....anyone know what ov'e done? the other 3 screws are holding it firmly in place but i need to sort it!...thanks in advance

 

[Broadside]

You have stripped the thread off the bolt or the stem. Find out which it is and get it replaced.

If you are mechanically minded (no offence but I don't think you are) then you could re-tap the stem, but at £20 for a replacement stem it is not really worth the hassle unless you already have the right equipment to do it.

 

[fossyant]

New stem time probably. Oops.

 

[RWright]

If you get anything made out of carbon let your LBS put it on for you.

 

[hero of valour]

ah thanks...i think ive stripped the screw....i can see some loose thread around it.....i'll roll into my speci shop tomorrow for a replacement

 

[hero of valour]

oh yeah and in addition to this will i be okay cycling tomorrow? its a 6 mile cycle into work until i can fix in my lunch?

 

[Pumpkin the robot]

You could have it helicoiled which may be a cheaper solution than buying a new stem? Any engineering firm should be able to do it for less than a tenner.

 

[sidevalve]

Unless you are very lucky it will be the stem not the screw that is stripped. Screws are usually steel stems are alloy [or poss something else even more delicate]. You could get it helicoiled but then you'd have to find someone to do it, get it to them, wait however long etc etc. Easier in the long run to just bite the bullet and buy another stem. If you shop around you can often find a replacement quite cheaply.

 

[Pumpkin the robot]

The joys of being able to fix things like this yourself If you are anywhere near Manchester I will fix it for you.

 

[mrandmrspoves]

Easy to do....which is why it is well worth buying a micro torque wrench. Light alloy parts such as stem clamps normally only need tightening to 4-6 nm maximum......but who knows what that feels like? Also when tightening any part like the handlebar clamp, work sequentially gradually tightening one bolt, then the bolt opposite, and so on (same as you should for car wheels).
Don't be tempted to bodge the stem and keep riding it......not worth the risk of the handlebars coming loose while your riding for a part that can probably be replaced for £15. (But if you know anyone with a tap & Die set they can re - tap it to take a larger bolt)

 

[HovR]

oh yeah and in addition to this will i be okay cycling tomorrow? its a 6 mile cycle into work until i can fix in my lunch?

I wouldn't... Handle bars coming off can be nasty.

Sounds like you over-tightened it or tightened the bolts unevenly. When tightening the bars on to a stem make sure you do each bolt up gradually and evenly.

 

[Pumpkin the robot]

If you take it to a larger size you would also have to drill the clearance hole on the clamp to a larger sizeand counter bore it as well, which is why I suggested the helicoil route, it enables you to use the same size bolt.
A torque wrench sounds like a great idea if the OP is stripping threads in everything! Every shed/garage shoukd have one.

 

[wisdom]

Good answers and advice by all.
One question.Whats the best size and make of torque wrench that will be suitable for bikes helt together with Allen screws

 

[HovR]

One question.Whats the best size and make of torque wrench that will be suitable for bikes helt together with Allen screws

Park Tool make good tools, so I imagine their torque wrench should be of a good quality (although expensive, it should last for life).

Torque wrenches normally come in two main sizes, a large and small. The large size will cover torques from around 20 to 60NM, depending on the model - Used for things such as tightening up wheel nuts, crank bolts (on square taper BB) etc. Generally the things which need this much torque are high strength bolts that you will struggle to strip, so you might as well just heave as hard as you can with a regular socket set.

The most useful size is the smaller size, generally covering torque values from around 2 to 15Nm, which are much more useful on a bike.

Most torque wrenches will come with a generic 1/4, 3/8ths, 1/2 inch drive etc, so you can get allen key, socket set and other attachments for them easily.

Take a look here for a list of bicycle torque values.

 

[wisdom]

Thanks fo the advice.
Will have a look at the park tools smaller one.Nice link for the torque values
Thanks again