Rotor bolts won't tighten?

[ishaw]

Just built a bike for my son, used some spare wheels I had (mavic crosstrail). On fitting rotors to the rear, 2 of the 6 bolts wimt tighten fully, they spin when they should stop/be tight. Bolts are new and thread locked, hubs dont show any signs of a crack around the bolt holes, though by design the holes aren't fully enclosed (weight saving I assume).

Is there anything I can do.other than apply more threadlock and hope? I dont want them to fail in use.

Mavic are trying to be helpful but have advised to retap. Not sure this will help though. They dont have spares for the wheel, so I'm hoping a solution can be found that doesn't require a new set of wheels.

Any ideas/solutions that have worked for anyone with a similar issue?

 

[mk one]

Hi, if the bolt is spinning and not tightening then the threads are shot. Threadlock needs threads, if there arent any then it will still spin.

You could fill the hole with liquid metal or similar and screw new threads, or Helicoil if you dont want to retap/

Mark

 

[mdvineng]

Check the bolts, some of the bolts out there are poor quality and actually undersized

 

[ishaw]

Check the bolts, some of the bolts out there are poor quality and actually undersized

I was thinking about trying other, longer bolts to see if there was a difference. Thanks.

 

[ishaw]

.....or Helicoil if you dont want to retap/

Mark

That might work, though doesn't that also need threads? Never done this before, what would I need kit wise to do this?

 

[mdvineng]

Check the bolts, some of the bolts out there are poor quality and actually undersized

I was thinking about trying other, longer bolts to see if there was a difference. Thanks.

I was more refering to the diameter, I have measured some M6 bolts at 5.4mm dia!!!

 

[mk one]

Doesnt the bolt spin both ways?

Been thinking and i doubt the threads in the hub are stripped, more likely the bolt.

Mark

 

[mattr]

Check the bolts, some of the bolts out there are poor quality and actually undersized

I was thinking about trying other, longer bolts to see if there was a difference. Thanks.

Sometimes find that the standard bolts don't go all the way through, so once a hamfisted first owner has stripped the threads, you might find a couple of turns of good thread at the other end.
If the face on the back if the lug is flat and perpendicular to the bolt axis, you might be able to nut them.
Helicoil would be the "proper" way to do it. Just need a drill bit, tap and a couple of inserts.

Unless the bolts are undersized!

 

[mattr]

Doesnt the bolt spin both ways?

Been thinking and i doubt the threads in the hub are stripped, more likely the bolt.

Mark

Steel bolt, aluminium hub?
All things being equal, it'll be the hub that's gone.

 

[mk one]

Steel bolt, aluminium hub?
All things being equal, it'll be the hub that's gone.

yeah, i was thinking the bolts were alu for some reason, sure ive stripped rotor bolts before though :?