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titanium bolts for stem use?

norbar

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
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4130biker said:
Simply a point that things breaking in that area can be bad and I don't see any reason to take risks in that area. Things don't have to be a tank to be reliable- see Thomson. I think everyone's assumption here is that ti bolts aren't as strong a similiar steel bolt. Are we wrong about that?



.
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Yes breaking in that area can be bad but it's the same argument people have with carbon bars and a zillion other parts "that can break" and bite your head off. The problem with your opinion is that while you don't advocate heavy stuff in areas where you tried lighter products you do in places where you have no experiance. Look at this topic. The only people who oppose the ti bolts HAVE NEVER TRIED THEM and the only case of failure shown is JD who did a stupid thing and run hollow ti bolts.
So is your theoretical assumption more important than real life testing?

Not to mention that many pros use ti bolts that are not hollow and live. Even some dirt jumpers.
 
4130biker

4130biker

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norbar said:
Yes breaking in that area can be bad but it's the same argument people have with carbon bars and a zillion other parts "that can break" and bite your head off. The problem with your opinion is that while you don't advocate heavy stuff in areas where you tried lighter products you do in places where you have no experiance. Look at this topic. The only people who oppose the ti bolts HAVE NEVER TRIED THEM and the only case of failure shown is JD who did a stupid thing and run hollow ti bolts.
So is your theoretical assumption more important than real life testing?

Not to mention that many pros use ti bolts that are not hollow and live. Even some dirt jumpers.
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I see your point and respect your opinion- I took the jump into cf cranks this year (something I never thought would happen) and they've been rad. I think it's just an individual comfort thing to some extent.
I think the way to do it would be to do research and find out if it's truly safe to do, as mentioned by a few others. If the stem is designed for it, I'm sure it's been tested and you're taking a risk on the research that a company did (which most are comfortable with).
I suppose if you do research and spend money, that your scenario could be safe, it's just not worth the work/or penalty for not doing the research TO ME for such a small reward.
 
Brian HCM#1

Brian HCM#1

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Sep 7, 2001
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norbar said:
But what it has to do with Ti bolts? Maybe to prevent death we should start using 1kg stems? Because that's what you are saying - let's use the heaviest option possible because Ti bolts are bad. Have you tried it? How many people do you know that use ti bolts in their stem have had any problems with them. I mean non hollow ti bolts. Same goes for other nay sayers in this topic. Because I only see wild speculation.
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It's easier to shear to shear the heads off Ti bolts. Always has been and always will.
 
Dogboy

Dogboy

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Apr 12, 2004
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tacubaya said:
Titanium Ti-6Al-4V Yield Strength: 800 MPa
7075 T6 Aluminum Yield Strength: 450 Mpa
Carbon Steel 1018 Yield Strength: 380 Mpa

Ti is badass. Hollow ti = retarded.

/thread.
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I'm no engineer, but shouldn't we be talking about Shear Strength? For direct mount stems (bolts into the crown) and disc adapters, shouldn't that be more applicable?
 
V

vikingboy

Monkey
Dec 15, 2009
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bizutch said:
The answer lies at Thomson. They will not use Ti bolts in their stems or seatposts.

That's really all anyone needs to know.
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Plenty of other companies do though, what's your point? Thomson make nice stems but hardly the reference are they? Did I miss the announcement!?
 
Sandwich

Sandwich

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vikingboy said:
Plenty of other companies do though, what's your point? Thomson make nice stems but hardly the reference are they? Did I miss the announcement!?
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um, yeah thomson kind of is the reference for components. They don't make ****. They make great, reliable stuff. It may not be the lightest or the cheapest, but it's pretty much the reference to compare all other companies by... The one part of your bike you'll never think about is your seatpost, if it's a thomson.


except for their direct mount stem and website....
 
S

StabprimoMonkee

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Aug 4, 2008
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@norbar: on account of carbon bars, they might be better nowadays. But 5 years ago I knew 6 riders who rode monkeylites, 4 had catastrophic failures, some of them twice. I'd use carbon handlebars immediately for their superb ride quality, but won't since defects in carbon manufacturing can be impossible to spot and failures tend to be unpredictable.

Disclaimer I did ride a carbon DH frame for 2 seasons and I liked it very much. Id also ride a carbon V10 any day.

For me Ti bolts for stem and brakes are in the same category as carbon bars. And I might even ride carbon bars when I am convinced that quality control on those things is up to task, but Ti bolts on stem? *shudder*
 
Udi

Udi

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vikingboy said:
Plenty of other companies do though, what's your point? Thomson make nice stems but hardly the reference are they? Did I miss the announcement!?
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Sandwich said:
um, yeah thomson kind of is the reference for components. They don't make ****.
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I agree with vikingboy, Thomson is a bit like CK, americans love them both but neither are anything spectacular, especially these days.

Thomson stems are rubbish, they might be well machined and finished, but have design flaws. I dealt with an elite and elite X4 twisting away on my steerer tubes at the slightest dingle for a long time before switching to an easton that clamped twice as hard, costed a lot less, and weighed the same amount.

I'm sure the seatposts are lovely, but again, probably better stuff out there for less money (I-Beam is light, cheap and effective).

CK is another big dollar US brand that relies on production quality and wank to compensate for sh!tty designs. Headsets without split rings? Not exactly a reference for anything. :)
 
Ian Collins

Ian Collins

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Oct 4, 2001
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Sandwich said:
The one part of your bike you'll never think about is your seatpost, if it's a thomson.
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while i love thomson seatposts and that's what i run, the one part of a bike that i never think about regardless of what i'm running is a seatpost, period....

thomson, sdg, race face, ****ty oe spec...whatever it is, i usually pay no mind because lets face it, compared to some other parts on a bike these days it can't be too hard to engineer a seatpost that works
 
R

roel_koel

Monkey
Mar 26, 2003
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Thomson stems are rubbish, they might be well machined and finished, but have design flaws. I dealt with an elite and elite X4 twisting away on my steerer tubes at the slightest dingle for a long time before switching to an easton that clamped twice as hard, costed a lot less, and weighed the same amount.

I would not say rubbish...but perhaps a little "outdated" especially now riders are running 750-800mm bars

I switched some weeks back from my trusty Thomson X4 to an Easton Haven and have found the Easton is noticeably stiffer when yanking hard on my Renthal 750mm bars, than the Thomson

I also got to try out the Renthal Duo which like the Easton was lighter and stiffer than the Thomson X4 - the Renthal looks absolutely stunning too :)

the Easton Haven is lighter (136gm for 55mm, compared to 178gm for X4 50mm and 146gm for Renthal Duo stem) and knowing Easton's track record I have no doubts about its strength

to get the Thomson X4 down into those weights you have to use Ti bolts which as I explained in a previous post led to horrible creaking and flexure whilst dirt jumping - no thanks!

both the Easton and Renthal are noticeably wider in the body and stem clamp area than the X4 which may partly explain the increased stiffness with wider bars

with the Easton stem actually looking like a wider, more high-tech / modernised version of the classic Thomson X4 design - the Easton "Top Lock" bar clamp method is just like Renthals and makes alot of sense in terms of clamping pressure on the bar

perhaps Thomson are due for a stem re-design / update?
 
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norbar

norbar

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Brian HCM#1 said:
It's easier to shear to shear the heads off Ti bolts. Always has been and always will.
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I'm not arguing that. What I'm arguing is if they are easy enough to worry about it? Real life evidence shows - not really.


StabprimoMonkee said:
@norbar: on account of carbon bars, they might be better nowadays. But 5 years ago I knew 6 riders who rode monkeylites, 4 had catastrophic failures, some of them twice. I'd use carbon handlebars immediately for their superb ride quality, but won't since defects in carbon manufacturing can be impossible to spot and failures tend to be unpredictable.

Disclaimer I did ride a carbon DH frame for 2 seasons and I liked it very much. Id also ride a carbon V10 any day.

For me Ti bolts for stem and brakes are in the same category as carbon bars. And I might even ride carbon bars when I am convinced that quality control on those things is up to task, but Ti bolts on stem? *shudder*
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I rode a 07 monkey lite DH (not the xc one) and it took a crazy amount of beating. Insta stops on trees and direct rock hits. I know it's good to be conservative but when you have multiple opinions it's a bit funny when the archairs engineers claim you should be dead 10 times because of the parts you're using. ;)





As for ti bolts - don't know about them for non direct mount stems but I run ti bolts in 3 different direct mount stem protos this year. None of which was designed for ti bolts. One of them would be around 100g with ti bolts, maybe less and I didn't notice any flex. Though the ~100g was only used for 3 days because the reasonable proto didn't arrive in time.
 
Ian Collins

Ian Collins

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Oct 4, 2001
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norbar said:
I'm not arguing that. What I'm arguing is if they are easy enough to worry about it? Real life evidence shows - not really.





I rode a 07 monkey lite DH (not the xc one) and it took a crazy amount of beating. Insta stops on trees and direct rock hits. I know it's good to be conservative but when you have multiple opinions it's a bit funny when the archairs engineers claim you should be dead 10 times because of the parts you're using. ;)





As for ti bolts - don't know about them for non direct mount stems but I run ti bolts in 3 different direct mount stem protos this year. None of which was designed for ti bolts. One of them would be around 100g with ti bolts, maybe less and I didn't notice any flex. Though the ~100g was only used for 3 days because the reasonable proto didn't arrive in time.
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i think the way i'd sum this up is that there are applications where ti bolts make sense(albeit wasteful) -- fork crowns, lever clamp bolts, derailleur pinch bolts, seatpost clamp bolt, rotor bolts etc....

....and there are applications where it's just not worth the risk(stem, and calipers)....common sense will tell you where the risk:benefit ratio isn't optimal, and DARWIN will take care of those who are too stupid and ignorant to understand that....
 
Sandwich

Sandwich

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Udi said:
I agree with vikingboy, Thomson is a bit like CK, americans love them both but neither are anything spectacular, especially these days.
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just like the brits and any single thing that comes out of the UK...nuke proof, Orange, etc....ZOMG it's the dogs bollocks!!!!!
 
norbar

norbar

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Ian Collins said:
i think the way i'd sum this up is that there are applications where ti bolts make sense(albeit wasteful) -- fork crowns, lever clamp bolts, derailleur pinch bolts, seatpost clamp bolt, rotor bolts etc....

....and there are applications where it's just not worth the risk(stem, and calipers)....common sense will tell you where the risk:benefit ratio isn't optimal, and DARWIN will take care of those who are too stupid and ignorant to understand that....
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Naah, I'm not a pussy. Darwin won't gonna beat me ;)
 
tacubaya

tacubaya

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Dogboy said:
I'm no engineer, but shouldn't we be talking about Shear Strength? For direct mount stems (bolts into the crown) and disc adapters, shouldn't that be more applicable?
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Same shiat man. Shear stress is just the average of the principal stresses (Sigma 1 and 2). Mohr circle relates the shear and normal stresses, so you can use yield strength as well. Many authors (including Gere) make tensile to shear conversions casually (for example AL USS is around 0.7 UTS)

Not all bolts fail on shear. Many materials such as steel tend to fail in tension rather than shear (being brittle).
 
tacubaya

tacubaya

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toodles said:
Whoa - absolute rubbish. Compare apples to apples mate. Carbon 1018 is complete rubbish - nobody would use mild steel as a bolt on anything but a toy store bike.
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HAB said:
Yeah, but who the fvck uses 1018 steel for stem bolts? IE e.13 used 12.8 grade bolts which IIRC have a yield strength north of 1 GPa. As in more than 6-4 Ti.
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I never said anyone used 1018 for bolts. Just a comparison on how a very commercial titanium is stronger than a known and fairly commercially available steels.

And btw, e.13 claimed to use "12.8 grade Dacromet" bolts, NEVER heard or read any data sheets about that. AFAIK 12.8 grade is not a valid bolt grade designation according to my knowledge of SAE and ASTM standards.

Jeez guys relax.
 
W

Wobbler

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Jan 22, 2006
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tacubaya said:
I never said anyone used 1018 for bolts. Just a comparison on how a very commercial titanium is stronger than a known and fairly commercially available steels.

And btw, e.13 claimed to use "12.8 grade Dacromet" bolts, NEVER heard or read any data sheets about that. AFAIK 12.8 grade is not a valid bolt grade designation according to my knowledge of SAE and ASTM standards.

Jeez guys relax.
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http://www.dacromet.com/

dacromet is the coating

hth
 
tacubaya

tacubaya

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yah, I know its a coating, but never heard of 12.8 grade designation... afaik dacromet bolts have the A490 ASTM designation (structural bolts)
 
S

Steve M

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Shear and tensile strengths don't tell the full story either, titanium is highly notch sensitive for starters - ie that huge helical notch that lets your Ti bolts rotate their way into your stem is weakening each bolt significantly compared to the stainless/hi-ten equivalents. http://cat.inist.fr/?aModele=afficheN&cpsidt=1116290

Seriously using Ti bolts in any structural application isn't a great idea. Of course not ALL of them will fail, but the potential for failure is far higher than it is with proper high tensile steel bolts. I can't think of anywhere I'd LESS like to snap on my bike than the bars/stem/headtube either. If you want to take the risk, go for it, but educate yourself on what can actually happen first.
 
Wa-Aw

Wa-Aw

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Jul 30, 2010
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Man up and use carbon fibre bolts with bamboo threads and a hollow ceramic core.


Stem bolts; SERIOUS BIZNESS.

This is what downhill racing is about people.
 
Udi

Udi

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Sandwich said:
just like the brits and any single thing that comes out of the UK...nuke proof, Orange, etc....ZOMG it's the dogs bollocks!!!!!
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Haha true. It's funny you can't rag on Australia because I don't think our country even makes any bike components worth talking about!
 
Sandwich

Sandwich

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Udi said:
Haha true. It's funny you can't rag on Australia because I don't think our country even makes any bike components worth talking about!
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how is that even possible? you guys have some of the very best racers, and the best minds in the biz, but you let NZ have all the fun???


back on topic, you really just have to ask yourself if 120g total is worth checking your bike every run or having that little voice in the back of your head...I guess I'm just beginning to accept that i'm different than a lot of posters, and resilience and reliability are far more important to me than a 38lb (vs. 40) on the tubes...
 
xy9ine

xy9ine

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^you'd love this - i had 40 ti bolts on my tmx (every bolt + ti profile bb spindle), which netted me what was probably the lightest tmx ever to have lived. what was the result of this exercise in futility (starting w/ a 20lb frame)? a svelte 47lbs. awesome. despite the arguable performance benefits, there's something strangely satisfying about replacing leaden & ugly old steel bolts w/ sweet sweet ti... its not rational, no.
 
Sandwich

Sandwich

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I'll give you that the 300 suspension bolts on the TMX may have been worthwhile, but if a shock bolt breaks, the circumstance is less likely to be fatal or paralizing...plus you're a pretty light dude, IIRC...?

I'll give you that replacing bolts can be mucho satisfying...when I do it on my Sunday, however, I'm going with grade 8 minimum, unless I can find 10 or 12. Rust be damned, I don't want those to strip out again. I figure I'll take a juicy dump before the next race, and the 12 grams I gain will be evened out.
 
tacubaya

tacubaya

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Socket said:
Shear and tensile strengths don't tell the full story either, titanium is highly notch sensitive for starters - ie that huge helical notch that lets your Ti bolts rotate their way into your stem is weakening each bolt significantly compared to the stainless/hi-ten equivalents. http://cat.inist.fr/?aModele=afficheN&cpsidt=1116290

Seriously using Ti bolts in any structural application isn't a great idea. Of course not ALL of them will fail, but the potential for failure is far higher than it is with proper high tensile steel bolts. I can't think of anywhere I'd LESS like to snap on my bike than the bars/stem/headtube either. If you want to take the risk, go for it, but educate yourself on what can actually happen first.
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Yeah, that is why the rear end of the Bugatti Veyron is held together by just 14 Ti bolts trolololol

Inb4 the sh1tstorm :D:D
 
Zoso

Zoso

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Jan 31, 2003
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I've seen E13 and Canfield(early version) DM stems break with steel bolts. I think the real issue in the stem discussion is 3 or 4-piece design versus 2-piece. If there are 3 or 4 individual parts (2 bar clamps, 2 crown mounts ala E13) then the bolts are taking a hell of a lot more force. I've got a racer on a Straitline 2-piece stem and we're running ti bolts throughout - mount and clamp bolts. I use anti-seize so the bolts can turn with no added friction to upset the torque wrench, and I use a click type torque wrench to set it to Straitline's spec. You'd be blown away how many bikes come through my shop with inconsistent/incorrect gaps between stem and face plate. People really don't pay attention to this very critical part of the bike. I see it as more of an install issue than the bolts themselves. JD's bolts were DRILLED ti, if you drill steel bolts you'll likely get the same problem.

The approach to what you do results in what you get.
 
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