Handlebar Clamp Bolts

robmanic1

'morning all
I want to replace the rusty bolts on my road bikehandlebar clamp, the stem is a Giant own brand type. Are the bolt sizes universal on these things? Anyone know where I can order some? (Looked on chainreaction but not sure what I need)

Cheers

robmanic1

Wiggle do them in the following sizes:
M4x10
M5x12
M6x16

Anyone know which size I need??

gkerr4

it's unlikely to be the M6 - most probably the M4

what size of allen key fits them? - if it is the 4mm allen key then you need the M4 and if it is the 5mm then the M5

robmanic1

Dunno G, bike at home, I'm at work, should'v checked before I came out. Anyone got an OCR2 out there who could check for me? I'd be most grateful

gkerr4

i would be 90% certain they are a 4mm

usually the stem bolts are 4mm and the top-bolt for preload is a 5mm

it would be unusual for a 5mm stem bolt.

(still not sure on the length though...)

mavigogun

gkerr4 wrote:

it's unlikely to be the M6 - most probably the M4

what size of allen key fits them? - if it is the 4mm allen key then you need the M4 and if it is the 5mm then the M5

A quick visit to McMaster-Carr demonstrates the Allen key socket size does not reflect the threaded shaft diameter of the bolt. Take a look:

https://www.mcmaster.com/#91292a137/=18sl6ag

cougie

I'd take them into your LBS and see what they have.

Matthewfalle

I'd go the local motor factor and take one in and pay 4p each for stainless.