Steel or Titanium Disc Brake Caliper Fixing Bolts?

Discuss light weight issues concerning mountain bikes & parts.

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skinnie
Posts: 39
Joined: Tue Feb 18, 2014 10:52 pm

by skinnie

Is aluminium ok?
I've found this ones: http://www.prototype.pt/product/disc-bolt
9,6 gr (12 pcs) 25,01eur
It's from a Portuguese company, but I think very similar to Token ones.
Carrera Scatto/Ultegra R8000 11s/Campangolo Shamal Mille

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

No, the continuous off centre loading/twisting when you brake will fatigue an aluminium bolt in no time.

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jimborello
Posts: 283
Joined: Sun May 31, 2009 5:07 am

by jimborello

I also use ti bolts on my mtb bikes with no problems.

Jmdesignz2
Posts: 272
Joined: Tue Jan 13, 2015 2:27 am

by Jmdesignz2

Ti bolts are fine

some use 3 ti and 3 ALU

I use teflon plumbers tape for just about any threaded application - serves both purposes, anti sieze and thread locker. Does not attract dirt like grease. Does not displace.

SebK
Posts: 114
Joined: Thu Sep 24, 2015 3:35 pm

by SebK

Nothing wrong with using threadlock with titanium .

Anyway I have ti bolts on all my bikes . I have the Extralite ones and some Schmolke carbon bolts for good measure .

joec
Posts: 100
Joined: Wed Mar 05, 2014 9:20 pm

by joec

Stainless is not a good option for loaded applications like this either, not good from a fatigue point of view, and also tends to gall, niot as bad as ti for galling though.

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Jmdesignz2 wrote:Ti bolts are fine

some use 3 ti and 3 ALU
I only use two bolts to hold my calipers on.

ooo
Posts: 1590
Joined: Sat May 21, 2016 12:59 pm

by ooo

titanium specific threadlocker:

LOCTITE 2432 is a blue, liquid, 1-part, medium viscosity, thixotropic dimethacrylate ester acrylic threadlocker with medium strength. It is designed for the locking and sealing of threaded fasteners which require normal disassembly with standard hand tools. It was especially developed for use on sensitive metals, like titanium, used in the nuclear industry.

LOCTITE 5772 is a medium strength, methacrylate-based thread sealant well suited to the locking and sealing of metal threaded pipes and fittings up to 3" in diameter. With PMUC approval, the product has low halogen and sulphur content and is designed for use in the nuclear industry on sensitive metals such as titanium.

LOCTITE 6482 is a green, low-viscosity, urethane methacrylate, acrylic, retaining compound which has a low halogen and sulphur content and was especially developed for use in the nuclear industry. The product is for bonding cylindrical fitting parts, particularly where strength at elevated temperatures is required. Applications include holding gears and sprockets on to gearbox shafts, and rotors on electric motor shafts. Suits sensitive metals such as titanium.
'

02GF74
Posts: 724
Joined: Thu Jan 13, 2011 4:04 pm
Location: Sunny UK

by 02GF74

I use M6 bolts for callipers and M5 for the disc rotor with blue loctite.

No problems with undoing, corroding or breaking.

... And these are the cheap Ti from far East on ebay.

ooo
Posts: 1590
Joined: Sat May 21, 2016 12:59 pm

by ooo

Some amazon comments suggest this for Loctitte 243/242 (regular blue threadlocker):

If you use this on aluminum, stainless steel, magnesium, titanium or some other inactive metal, you should also use primer ("Klean 'n Prime").

LOCTITE Klean 'N Prime Anaerobic Activator
Permatex Surface Prep Activator for Anaerobics

What you think about smaller bottle cage bolts? Titanium + low strength (purple) threadlocker ? Alloy + low strength (purple) threadlocker ?
'

youngs_modulus
Posts: 668
Joined: Wed Sep 20, 2006 1:03 am
Location: Portland, OR USA

by youngs_modulus

joec wrote:
Sun Sep 27, 2015 12:34 pm
Stainless is not a good option for loaded applications like this either, not good from a fatigue point of view, and also tends to gall, niot as bad as ti for galling though.
Nitpick: galling is only a problem when threading stainless fasteners into stainless threads or Ti fasteners into Ti threads. Most caliper mount threads are either aluminum or brass, so both stainless and Ti (grade 5, AKA 6/4) are fine for caliper bolts.

Non-nitpick: it's absolutely false that "stainless is not a good option for loaded applications" or that stainless is "not good in fatigue." JoeC, I have no idea why you're claiming otherwise. Can you cite a source?

Many stainless alloys' fatigue properties are as good or better than those of carbon steel. Fatigue is a major design consideration for spokes, and spokes are overwhelmingly stainless. And nearly all OEM caliper bolts are stainless steel.

UpFromOne
Posts: 1181
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

ti with a small dab of anti-seize.

don't bother with aluminum, one day you'll manage to strip the head, and have to get out the drill.
don't ask me how i know.

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