Stem bolts : What size?

[RSV_Ecosse]

What size stainless allen headed bolts are usually used as the 4 fitted to road bike stems?. I want to replace mine as they are looking a bit dull and worse for wear but I have no idea what size they are?. Had a dig around online and some say they will likely be M5x16 but I have also read of a few other sizes that are possibles?. I once knew a guy who could simply look at any screw, bolt whatever and tell you exactly what size it was but unless a component has the size marked on it, I'm hopeless at that!!.

Or is there a way to measure the things and tell?. Cheers.

 

[Rob3rt]

They are M5x20 (with a 4mm hex head) on this fuji stem ive got lying on my desk.

To measure take one out and hold against a ruler, or if you are fancy (like me - jokes) then use a set of digital (or manual) calipers or micrometer to tell measure.

 

[RSV_Ecosse]

Ta.

Is it ok to just use anodised alloy bolts in the stem or should they really be stronger, like titanium for example?.

 

[Rob3rt]

I have no idea if Im honest, I used the bolts that came with the stem when I changed the stem over from the Fuji one to a better one.

If in doubt go with the stronger option, dont want something to sheer when you got your weight on it and go faceplanting.

 

[e-rider]

DON'T use alloy bolts - no no no! Not strong enough for stems. All stems come with either stainless steel or titanium bolts (or for example, zinc plated steel on cheapo crap stems).

 

[RSV_Ecosse]

Cool, I'll grab a set of Ti ones online somewhere.

Cheers for the info folks.

 

[redddraggon]

DON'T use alloy bolts

Huh, steel and the titanium used for bolts are alloy