AM Classics with Ti bolts

[milky4130]

Does anyone know why AM CLASSICS do not recommend using Titanium bolts for the rotors with their hubs? Thanks

[milky4130]

Where is JB when you need him?

[Cruz Addict]

Guessing here but thinking because they are weaker than the alternatives or they are stronger than and cause additional stress on the hub, on an AM wheel running 203mm rotors being used properly I assume the forces would cause huge stress on the bolts, pushing them to the limits of their capacity and possible break. Broken bolts mean possible injury means possible law suite?

As I say I don't know but that's a complete guess.

[kosmonooit]

I am sure it won't be because Ti bolts are weaker .... they make jet engine turbine blades out of that stuff.

[milky4130]

I'll be using 160mm's but that has nothing to do with it as AM wouldn't have an idea what rotors I would've used at the time of publishing their leaflet/installation manual.

[ALLMTB]

Perhaps something to do with the corrosion between alu and ti...?

[milky4130]

"Using a rotor that is not reinforced and/or titanium bolts highly increases your chance for brake failure, don not use these products with AM CLASSIC disc hubs" from the installation page.

[Azonic]

Buy a pack of 6 and just use a Ti bolt every 2nd one. So 3 Ti, 3 steel per wheel. Just to be sure.

 

That being said, for a long time I only used 3 bolts per rotor, never had a problem, and that was on AM Classic hubs as well.

[milky4130]

Buy a pack of 6 and just use a Ti bolt every 2nd one. So 3 Ti, 3 steel per wheel. Just to be sure.

 

That being said, for a long time I only used 3 bolts per rotor, never had a problem, and that was on AM Classic hubs as well.

Shucks you taking the WW to a whole new level. I doubt I'll risk 3 bolts per rotor. I have the pack of 12 Ti bolts alteady, bought it some time ago, now just not sure should I or shouldn't I.

[Azonic]

Shucks you taking the WW to a whole new level. I doubt I'll risk 3 bolts per rotor. I have the pack of 12 Ti bolts alteady, bought it some time ago, now just not sure should I or shouldn't I.

 

Geoff Kabush uses 3 bolts per rotor. If it lasts for him I'm sure I'll be fine. But ja, I would go criss/cross 1 ti, 1 steel, 1 ti, 1 steel. Three of each per rotor.

[javadude]

As mentioned, there are issues with galvanic corrosion using Ti bolts on aluminium.

[Steven Knoetze (sk27)]

As mentioned, there are issues with galvanic corrosion using Ti bolts on aluminium.

 

Jip, once they go in, they may not come back out.

Stick with the stainless bolts

[Bat-ass]

Geoff Kabush uses 3 bolts per rotor. If it lasts for him I'm sure I'll be fine. But ja, I would go criss/cross 1 ti, 1 steel, 1 ti, 1 steel. Three of each per rotor.

 

Geoff Kabush has sponsored medical insurance! And him having a catastrophic crash will get 15 000 000 you tube and TV hits.... Good for sponsor coverage!!? Personally, i think running 3 bolts per rotor is grounds for a Darwin award.

 

AM hubs come with a red reinforcing ring for use with unsuported rotors ie. rotors with no meat on the rotor between the bolts (formula rotors). This is because the hub also lacks meat around the rotor bolt mounts. There is nothing wrong with the AM hubs if you follow the instruction advice.

 

I cant remember, but i think it also warns against the use of Ti bolts.

Edited August 16, 2013 by Bat-ass

[kosmonooit]

As mentioned, there are issues with galvanic corrosion using Ti bolts on aluminium.

 

That makes sense, Bit of googling throws up some more info.

 

Assembly guide: Titanium frames & parts

 

"With titanium it's really important to use plenty of anti-seize compound wherever and everywhere Ti comes into contact with any other metal, including more Ti. This is to prevent gauling, which is an electro-chemical reaction that effectively welds Ti & other metals together resulting in totally seized parts that cannot be separated without causing serious damage.

 

There are a number of good anti-seize compounds on the market and the most common of these are copper based. These work but tend to leave copper coloured residues in all gaps and boundary surfaces that can be really hard to remove."

 

 

In boating this is also an issue and you get some specific compounds:

 

Tef-Gel

 

"The function of Tef-Gel in eliminating dissimilar metal corrosion is the elimination of electrolytes from entering the interface of the metallic surfaces. Tef-Gel paste contains 40% PTFE powder and 0% volatile solvents, no silicones or petroleum solvents to evaporate, which would leave voids for electrolytes to be drawn into creating a galvanic cell. When both surfaces are coated and mated with Tef-Gel there are no voids for electrolytes (saltwater) to be drawn in by capillary action over extended periods of time."

 

I've used some specific Ti Assembly compound (as instructed) obviously to prevent that, "Ti Prep" that I got from Toronto Cycles where I order my Ti bolts from

 

Its a Finish Line product - haven't seen it here anywhere.

[Johan Bornman]

I don't think the issue is corrosion. Ti is successfully used as bolts in many other bicycle parts without any issues at all.

 

I think it has to do with Ti's weak shear strength, compared to steel. Disc bolts are constantly subjected to shear forces and Titanium (depending on the specific alloy) has a shear modulus of 41400 MPa whereas steel is 793000 Mpa. Steel is thus twenty times stronger.

[Johan Bornman]

Geoff Kabush uses 3 bolts per rotor. If it lasts for him I'm sure I'll be fine. But ja, I would go criss/cross 1 ti, 1 steel, 1 ti, 1 steel. Three of each per rotor.

Why make life so complicated?

 

This Kalabash oke is really stupid.

Edited August 16, 2013 by Johan Bornman