Specialized Allen Bolt Sizes

[beatlejuice]

I am replacing the bolts on my Sirrus. The diameter of the water bottle holder, panner mounts etc bolts is 5mm? Please correct me if I am wrong. Thanks

 

[musa]

I would of assumed they come as standard across all

Ie universal

 

[mcshroom]

I'd expect so. All modern bikes I've used have M5 bolts (5mm) for bottle cages, mudguard mounts etc.

If you are looking at replacing all the bolts then look for socket cap stainless M5 bolts from Ebay. Far cheaper than buying 'cycle specific' ones and the come in a variety of lengths. (The socket cap is because they are harder to round off than the button/dome capped alternatives)

 

[Kins]

I'd expect so. All modern bikes I've used have M5 bolts (5mm) for bottle cages, mudguard mounts etc.

If you are looking at replacing all the bolts then look for socket cap stainless M5 bolts from Ebay. Far cheaper than buying 'cycle specific' ones and the come in a variety of lengths. (The socket cap is because they are harder to round off than the button/dome capped alternatives)

erm my bottle cages are 10mm length, I presume the thread pitch will be the same as well when buying non cycling ones?

 

[mcshroom]

erm my bottle cages are 10mm length, I presume the thread pitch will be the same as well when buying non cycling ones?

They should all be the same pitch. 24tpi IIRC

 

[Profpointy]

They should all be the same pitch. 24tpi IIRC

Now now, don't be mean....the guy's asked a sensible question, so if you're going to be a smart arse and mix units at least give the right answer.

M5 (ie 5mm diameter) screws are 0.8 mm pitch. (if they are indeed M5 - which they almost certainly are)

An older bike could well have an old imperial or cycle specific thread - in which case you'll have to measure it.

 

[Kins]

Cheers chap.

I presume they go up in quality the higher the A number like A2, A4 etc or is that wrong way round?

 

[Profpointy]

Cheers chap.

I presume they go up in quality the higher the A number like A2, A4 etc or is that wrong way round?

Yes and no. For stainless fasteners, the A number is basically how stainless it is. A4 is "very" stainless, whilst A2 is "ordinary" stainless. A2 is absolutely fine (ie genuinly fine, rather than merely good enough) for bike related stuff. If you're building apparatus for a chemical plant you might want to go for A4.

On another note, neither is entirely ideal for high stress use, in which case you want 10-8 or (better) 12-9 (neither being stainless) but basically there's virtually nothing that high stress on a bike bolt-wise.

 

[Supersuperleeds]

Mine take a 4mm allen key, I have an Allez

 

[Andy_R]

As a rule of thumb with allen bolts, M4 uses a 3 mm allen key, M5 uses a 4mm key and M6 uses a 5mm key. The definite way to measure the size of the bolt is to measure across the treads with a set of callipers though.

 

[02GF74]

^^^^ as he said re: stainless and streed components - not that it applies to bottle case; I have used aluminium alloy bolts to hold a cage + water bottle without any problems.