Bolt size question.

[SouthCoastRetro]

Chaps, I'm after some advice if you could please, my bike came with a couple of exposed holes which im assuming are rack mounts (though im not sure why?), anyway I'd like to plug the holes (they are threaded) with a nice couple of anodised bolts but I'm unsure of size. I'm estimating M6 as the holes don't look huge and the M5 I have already are too small but not by much. Am I right in saying M6 in your opinion?

I apologise in advance if anyone feels this is a stupid question. Just wanting to make sure.

 

[hamster]

That's odd, usually rack mounts are M5. A few specialist tourers use M6 for the bottom bolt that takes the load weight on the dropout.

If you use Ano bolts then be sure to smear them with copperslip before fitting or they are likely to seize into the frame.

 

[SouthCoastRetro]

Re:

Thanks for the copper slip tip, I'll bear it in mind. The bikes a brand new Cube 29er which made me think of M6. There aren't any bottom mounts for a rack which I thought odd given the holes at the top of the seatstays? Thanks for the tip though.

 

[02gf74]

cube are german so will be metric.

my money is on m5 but without seeing the bolt and bike is just speculation.

what do you mean by m5 being too smal? are they dropping in without touching the sides of the hole or are a bit loose and wobbly as you screw them in? the latter situation is quite common, and the bolts will tighten once the head bottoms out.