Using 5 bolts on a disk rotor

[Ethandp]

Im not sure how it got to this point but my friend brought me his bike and said the back brake wasnt working at all. I quickly realised the rotor wasnt spinning with the wheel, upon closer inspection I saw that there were no bolts. I looked more and saw the 1 hole had been ripped open. I was just wondering if I get bolts and use 5 if it will work well and not cause any damage.

[betaboy]

34 minutes ago, Ethandp said:

Im not sure how it got to this point but my friend brought me his bike and said the back brake wasnt working at all. I quickly realised the rotor wasnt spinning with the wheel, upon closer inspection I saw that there were no bolts. I looked more and saw the 1 hole had been ripped open. I was just wondering if I get bolts and use 5 if it will work well and not cause any damage.

What size is the rotor? The bigger the size, will of course affect the stress levels on hub etc. Is it not possible to have the hole rethreaded at some stage?

[Ethandp]

@betaboy

It is a 160mm rotor. It is not possible to rethread the hole as the top half of metal has snapped off

[DieselnDust]

Just use 3 bolts. There has to be a symmetrical anchoring or the rotor will warp. Bear in mind the rotor will be less stiff now especially when hot so be careful  with long descents.

hopefully your friend is not more than 90kg

[LBKloppers]

Been riding with 5 bolts for ages. The direction of the force through the bolt shafts is much less than the total shearing force possible from braking. ie. other things will go wrong long before you shear five bolts.