Stainless or titanium?

[Boxered]

my front caliper bolts are looking very shabby, so I want to replace them. Am I correct in thinking that titanium bolts are much stronger than stainless a70/80 grade? or does the snake oil philosophy apply here?
Also, as my calipers are BMW badged brembos, I think the size is m8 32mm, should I use 35mm or would it be better to use 30mm length?

any help much appreciated.

Steve

[madman]

Titanium can be stronger or weaker than SS, depends on the grade. I have loads of titanium bolts on my bike, but there are Tornado aircraft bolts, and so are top quality. You ask about strength, does that mean you have broken some? If not why do you want them stronger? Titanium of the correct grade are much lighter for the same strength as SS.

[throttlemeister]

my front caliper bolts are looking very shabby, so I want to replace them. Am I correct in thinking that titanium bolts are much stronger than stainless a70/80 grade? or does the snake oil philosophy apply here?
Also, as my calipers are BMW badged brembos, I think the size is m8 32mm, should I use 35mm or would it be better to use 30mm length?

any help much appreciated.

Steve

The standard, nicely colored replacement Titanium bolts you can buy at motorcycle shops are not suitable for brakecalipers. They should only be used at non-critical and no stress applications.

[iandunn1100ss]

I use ti bolts from pro bolt in all my bikes calipers and disc bolts and have never had an issue with them and the finsh is lovely ,but using ti is not cheap.

[throttlemeister]

Just because you haven't had an issue, does not mean they are suitable. Unless the manufacturer specifically specifies the bolts are (suitable) for things like brake calipers, rotors or whatever, these bolts should not be used for these applications.

[winger]

I'd go stainless,and thats from someone who has an S with barely a non Ti bolt on it,includeing filler plugs and rear wheel bolts,if you've already done the carbon fibre body panels dymags etc,then it's the next step,but otherwise i'd go stainless every time and save the money.

[Boxered]

Titanium can be stronger or weaker than SS, depends on the grade. I have loads of titanium bolts on my bike, but there are Tornado aircraft bolts, and so are top quality. You ask about strength, does that mean you have broken some? If not why do you want them stronger? Titanium of the correct grade are much lighter for the same strength as SS.

The reason I ask is that I'm aware that strictly speaking, ss bolts are not as strong as the ht steel originals, so, if Ti are any stronger, then I'd go for those on safety grounds.
this is the company I was thinking of using
http://www.bsr-aerotek.com/store/index. ... th=271_368
they claim to use aircraft grade, I'm not interested in coloured bolts, just the nearest shiny direct replacement that I can get.
Can anyone can point me to a better supplier? I know Ti is not cheap, but 4 bolts aint gonna break even my meagre bank

thanks Guys

Steve

[iandunn1100ss]

I think if you buy bolts marked as disc bolts then there may be a small chance that they are up to the job.

[madman]

Looked at the website and the only thing that would worry me is the fact that they are quoted as a titanium alloy and are shiny. The aircraft titanium ones that I have on my bike are a dull blue gray. They also quote that they are rolled threads, I did not think that any supplier offered bolts with cut threads these days!
I do know that if I put both a titanium bolt and a steel bolt on an anvil, heat them with a blowtorch and hit them with a lump hammer, the steel one will squash but the titanium one will still screw in without distortion. I wonder if the bolts supplied by the web site will do that.
I believe that the Tornado bolts which I have all over my bike are very expensive, some costing more than £50 each, and that is a bulk price.
Perhaps you should find a mate in the RAF who works on fast jets, they throw many away.

[Boxered]

Thanks Madman, I guess stainless is the way to go then.

Cheers
Steve

[iandunn1100ss]

I have had ago at trying to kill a ti bolt and stainless and the stainless broke with some force but the ti was massively strong. but i am no expert and this was just a crude test for peace of mind as i did not want any problems at any track day braking down from 140+.

[Boxadog 2000]

Rolled threads are not cut they are er rolled ie made by deformation of the parent material which increases strength, you can easily tell a thread that has been rolled the thread is of a larger diameter than the shank or plain section of the bolt.

Titanium is an alloy ! most commercially used is 6AL4V Ie 6 parts aluminium 4 parts vanadium.

PRO BOLT advertise bolts specifically for brake calipers and stress areas.

Bob

[oyster]

Somewhere, a while ago, I posted the weight saving of ti over standard when I got some buckshee rear disc bolts. It amounted to about the same as a cheap ball point pen. I have replaced most accessible bolts with stainless. Unless you are a plane mechanic with access to free ti, it's certainly cheaper by 75%.

[Boxered]

Rolled threads are not cut they are er rolled ie made by deformation of the parent material which increases strength, you can easily tell a thread that has been rolled the thread is of a larger diameter than the shank or plain section of the bolt.

Titanium is an alloy ! most commercially used is 6AL4V Ie 6 parts aluminium 4 parts vanadium.

PRO BOLT advertise bolts specifically for brake calipers and stress areas.

Bob

Cheers Bob, time to call pro bolt then.

thanks to all for your replies.

Steve

[madman]

A rolled thread can also be the same diameter as the plain shank part of the bolt and does not need to be proud. The reason for rolling rather than cutting a thread is that it preserves the grain of the metal (yes metal does have grain) instead of cutting it, which would decrease the shear strength of the thread itself.