Cube thread size for mudguard fittings help.

[Cuberider]

Trying to fit SKS mudguard set to my Cube nuroad but no bolts or screws from the mudguard set fit the thread on the bridge or forks or even to attach to the axle bit. . Anyone got any idea what size I need please? Wiggle suggest I go to b and q !! The Nuroad pro comes complete with guards so they must for somehow !! Any help gratefully received.

[Brucey]

you should be able to get this information from Cube?

FWIW the most common thread size to fit mudguards to the frame is M5x0.8mm. Where there is a clear-drilled hole (for a nut and bolt) it is more likely to be a 6mm hole. The bolts for these fittings vary from bike to bike and are not supplied with mudguard sets. You can buy them (and washers, nylock nuts etc) in stainless steel from screwfix, toolstation, etc. BTW M5x0.8 capheads are useful anyway because they fit bottle bosses.

cheers

[alexnharvey]

Following on from what Brucey writes, you can of course use a bottle cage bolt to check the thread size of your mudguard fittings

[Cuberider]

Thanks for the advice chaps, I'll get on with it.

[Cuberider]

Turns out on my Cube they are M4 and not M5 , great advice to check bottle cage bolts as they do fit

[Gattonero]

One word of advice: this new fashion of road bikes with MTB tyres and fitting for mudguards (hold on, weren't they already called "audax bikes" ??) got some so-called bike designers to fit M4 rivnuts, obviously not knowing that its not a good idea.
I've seen bikes with the rivnuts coming off by either overtighten bolts or fatigue. An M4 thread is easy to cross-thread, and cannot be tightened more than a certain amount (I'd say, 4nm at most on a carbon frame) so the use of a low strength threadlock if mandatory.
And yet, the cross section of an M4 rivnut is too small to provide long term durability on materials like carbon fiber or aluminium, so is very important the other fixing points make for a very stable assembly.

[Brucey]

the other thing that you see quire often is M5 nutserts fitted with aluminium screws (and no grease...) from the factory. After one British winter they are often in for good. And they can still be pulled out of the frame too. Only yesterday I nearly ran over something small lying in the road, went back and picked it up; it was an M5 nutsert complete with aluminium bolt and part of something still fitted; presumably having been wrenched free from a frameset.

cheers

[Gattonero]

the other thing that you see quire often is M5 nutserts fitted with aluminium screws (and no grease...) from the factory. After one British winter they are often in for good. And they can still be pulled out of the frame too. Only yesterday I nearly ran over something small lying in the road, went back and picked it up; it was an M5 nutsert complete with aluminium bolt and part of something still fitted; presumably having been wrenched free from a frameset.

cheers

Ought to be another winning one, from those people that would design a bicycle to look good on the monitor: "and here is a 1/2" round section seatstay end..." "put the rivnut there, he'd be ok..."