Alloy Bolts OK to use here ?

Discuss light weight issues concerning mountain bikes & parts.

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Ty
Posts: 139
Joined: Thu Aug 05, 2004 3:31 am

by Ty

Do you think it would be OK to change the holding bolts on these RC31 fork Brake bosse clamps from steel to Alloy bolts ?

I realize I would save very little (around 8-10 grams) for all four bolts, but I already have some spare 7075 T6 aluminium M5 bolts to hand.

These are the bolts which lock the brake arm holders on to the carbon legs of the RC31 Fork.

I ride exclusivley on the road (London) but I don't expect that makes any difference to the loads on these clamps

Cheers for any insights

Ty
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Frankie - B
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Joined: Mon Jun 02, 2003 8:17 am
Location: Drenthe, Holland

by Frankie - B

Ty, i think that if you can use Al bolts to screw your v's to the fork/frame, you can use em in your brake boss clamps.
'Tape was made to wrap your GF's gifts, NOT hold a freakin tire on.'

Ty
Posts: 139
Joined: Thu Aug 05, 2004 3:31 am

by Ty

when you screw your V's to the frame, the V's go 'over' the brake boss taking all the side forces, whilst the screws just hold it in position.

I have not explained that very well, but just look at your V's, if you take away the bolts they will stay there because they sit 'on' the bosses.

I think the forces on these may be different.

anyone?

extralite
Posts: 16
Joined: Mon Feb 16, 2004 8:31 pm
Location: Llanelli

by extralite

Pace recommends that the M5 bolts are tightened to 2.5Nm. This is the limit that aluminium bolts can be tightened to. I have used aluminium bolts on my RC31's for over a year with no trouble - I tightened them to 2.4Nm. Take care not to overtighten the bolts - aluminium bolts would be then safe to use.

Ty
Posts: 139
Joined: Thu Aug 05, 2004 3:31 am

by Ty

extralite wrote:Pace recommends that the M5 bolts are tightened to 2.5Nm. This is the limit that aluminium bolts can be tightened to. I have used aluminium bolts on my RC31's for over a year with no trouble - I tightened them to 2.4Nm. Take care not to overtighten the bolts - aluminium bolts would be then safe to use.


thanks for the reply,

this then raises another question, how do I put 2.4 Nm on to the bolts without a torque wrench ?

I have one but it starts at 19 nm ! :(

again any help mucho appreciated

Ty

extralite
Posts: 16
Joined: Mon Feb 16, 2004 8:31 pm
Location: Llanelli

by extralite

As long as you use normal length allen keys, tightening the bolts by feel should be alright. When I tightened the aluminium bolts to 2.4Nm there was a slight bend in the bolts. Just be careful not to overtighten them - you should be able to notice the bolts bending significantly if you tighten them too much.

Ty
Posts: 139
Joined: Thu Aug 05, 2004 3:31 am

by Ty

thanks for the info extralite :D

I will do just that !

Ty
Posts: 139
Joined: Thu Aug 05, 2004 3:31 am

by Ty

one last question should I grease 'em before insertion or leave 'em dry or even put a drop of locktight on ?

cheers

The man with no front brakes

extralite
Posts: 16
Joined: Mon Feb 16, 2004 8:31 pm
Location: Llanelli

by extralite

I would use grease or anti-seize on them. I used anti-seize on my aluminium bolts. That way, you can be sure that you will be able to get the bolts loose easily if you ever want to remove the brake clamps.

Ty
Posts: 139
Joined: Thu Aug 05, 2004 3:31 am

by Ty

Many thanks extralite!

here for you are 8 smilies

:D :D :D :D :D :lol: :D :)


Ty

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