Seminar: Titanium (a question)...

[catulle]

Would someone please enlighten my obnubilated mind in regards to the qualities of the different types of Titanium tubing used for building bicycle frames? I see that there are 2.5 Ti tubes and 6.0 and so on; what's the difference, please? Why? Thank you so much.

[Jason E]

3Al/2.5V frames are built from 3Al/2.5V titanium alloy, or titanium alloyed with 3% Aluminum and 2.5% Vanadium. This is a great material to build a frame from. It has an incredible strength to weight ratio and is still resilient enough to withstand alot of flex without permanent damage. This is what almost all of the highest quality titanium bike frames are made from.

6Al/4V alloy is 6% aluminum and 4% Vanadium. The problem is that the weld reduces the strength and resilience of the tube. In addition, 6/4 can only take about half the elongation that 3/2.5 can before it's permanently damaged. This makes a bike that's at best just a little stronger, but maybe less able to absorb punishment, also more expensive.

The Vanadium and Aluminum add to the strength. I believe that although Ti without the Al/Va has more elongation, the addition of the Al/Va doubles the strength.

(I am also sure someone can correct me.)

[Fat Robert]

one costs a lot

one costs more than a lot

a good builder can make a good bike out of either

[catulle]

3Al/2.5V frames are built from 3Al/2.5V titanium alloy, or titanium alloyed with 3% Aluminum and 2.5% Vanadium. This is a great material to build a frame from. It has an incredible strength to weight ratio and is still resilient enough to withstand alot of flex without permanent damage. This is what almost all of the highest quality titanium bike frames are made from.

6Al/4V alloy is 6% aluminum and 4% Vanadium. The problem is that the weld reduces the strength and resilience of the tube. In addition, 6/4 can only take about half the elongation that 3/2.5 can before it's permanently damaged. This makes a bike that's at best just a little stronger, but maybe less able to absorb punishment, also more expensive.

The Vanadium and Aluminum add to the strength. I believe that although Ti without the Al/Va has more elongation, the addition of the Al/Va doubles the strength.

(I am also sure someone can correct me.)

This adds to my knowledge a good 100%. Thank you. How about weight? Which would be heavier? Is the difference significant? Thank you.

[Grant McLean]

This adds to my knowledge a good 100%. Thank you. How about weight? Which would be heavier? Is the difference significant? Thank you.

All titanium weighs the same.

All steel weighs the same.

All aluminum weighs the same.

Two frames (made from the same material) the lighter frame is made with less
material than the heavier one. Uber-strong materials can have enough strength
to make up for the use of thinner tubes. This has a better strength
to weight ratio. The 6/4 ti is stronger than the 3/2 even though the
materials weigh the same, the theory is that you could build a lighter frame
from the stronger alloy. The trick is that "strength" is only 1 property.
It's a balance to create the ideal properties in a tubeset.

Also, there are limits to the least amount of material you can use.
Thinner tubes are less stiff, thinner tubes are more fragile (think bear can)

Different alloys of the same base material have the same stiffness too.
So larger diameter thinner tubes is the way to create a lighter, stiffer frame,
but there are limits.

g

[cpg]

All titanium weighs the same.

All steel weighs the same.

All aluminum weighs the same.

Two frames (made from the same material) the lighter frame is made with less
material than the heavier one. Uber-strong materials can have enough strength
to make up for the use of thinner tubes. This has a better strength
to weight ratio. The 6/4 ti is stronger than the 3/2 even though the
materials weigh the same, the theory is that you could build a lighter frame
from the stronger alloy. The trick is that "strengh" is only 1 property.
It's a balance to create the idea properties in a tubeset.

Also, there are limits to the least amount of material you can use.
Thinner tubes are less stiff, thinner tubes are more fragile (think bear can)

Different alloys of the same base material have the same stiffness too.
So larger diameter thinner tubes is the way to create a lighter, stiffer frame,
but there are limits.

g


Yes, but what one makes me go faster? Come on man, give us the silver bullet. :)

Curt

[Grant McLean]

Yes, but what one makes me go faster? Come on man, give us the silver bullet. :)

Curt

I find I don't ride too good after too many silver bullets... :)

g

[Tracer]

I find I don't ride too good after too many silver bullets... :)

g

Good taste in bikes, bad taste in :beer:

Chris

[catulle]

All titanium weighs the same.
All steel weighs the same.
All aluminum weighs the same.
Also, there are limits to the least amount of material you can use.
Thinner tubes are less stiff, thinner tubes are more fragile (think bear can)
g


Beer...? Wazzdat...? I thought that one pound of steel was heavier than one pound of aluminum. :eek: No, really, thank you. Great answer.

[Tom Kellogg]

Another poke at the hornets' nest ...

Tensile strength: 6/4- 170,000 3/2.5- 134,000
Yield strength: 6/4- 160,000 - 183,000 3/2.5- 116,000
Elongation: 6/4- 10% 3/2.5- 15%
Elas. Mod. (10^6 PSI): 6/4- 16.5 3/2.5- 15
Shear Mod (10^6 PSI): 6/4- 6.38 3/2.5- 6.5
(Ti-3/2.5 - CWSR, Ti-6/4 - CW)

Ok, I'll try to keep it brief. A few points:
6/4's higher tensile strength (~21%) is irrelevant since Ti frame tubes simply don't break in tension. So forget tensile strength.

Yield strength- this can be a pretty big deal since ultra thin tubes need higher yield strength to keep from either "beer canning" or being dented in a crash (or by running into a garage door frame.) In the real world, cold worked 6/4 tubes are pretty close to impossible to buckle while 3/2.5 tubes are only super tough compared to ANY other material.

Elongation, the amount of stretch a material will allow before failure. Again, pretty much irrelevant in the case of Titanium.

Elasticity Modulus, or bending stiffness; 6/4 is about 15% stiffer than 3/2.5 in bending, all other things being equal. Rarely are ANY of the variables equal though. Since only a few frame tubes are actually stressed in bending, 6/4, while very cool, does not add a lot of value.

Shear Modulus, or torsional stiffness; 3/2.5 is at best about 2% stiffer than 6/4 in torsion. In the real world, bubkis, nada, zilch, zip ...

So, where are we? If you had one frame of each with the same diameters and gauges, I very much doubt that ANYONE could feel any difference. Yes, the 6/4 frame would be considerably tougher in a "get off," but the 3/2.5 would be so tough anyway, that it is pretty much silly to talk much about it.

6/4, as a frame material, does give a designer more latitude if they are trying to make hyper light bikes because of that very high yield number. Larger diameter / thinner wall tubes can be very reliable when made out of 6/4. BUT, boy does the stuff cost a bunch to get in the sizes and wall thickness that make it all worth it. The production 6/4 tubing out there really does not take advantage of what can be achieved, and therefore does not offer enough advantage over your typical 3/2.5 tubing.

When it comes to dropouts, it is a different story. 6/4 strip is relatively inexpensive, and with its super high yield strength, it makes a bomb proof dropout. Kind of useful for those who insist on shifting into their spokes or picking up big sticks in their chains. As it turns out, 6/4 welding wire is the ticket too. It welds easier than most other alloys.

So warm up the spit balls and have at it...

[catulle]

Now I'm way above and beyond where I was. Thanks. Just asking, does it make any sense to build a lugged Ti frame...?

[Tom Kellogg]

Nah. Cecil Beringer built two many years ago and put the two older Stetina brothers on them for a while. A big problem back then was that everything was CP titanium. He was actually able to solder them up, but there were of course corrosion issues with the silver solder. Since properly welded titanium is not appreciably weakened, soldering doesn't help it like it helps some steels. Enough. The weekend calls.

[Dekonick]

Where else could one get answers from top builders like TK, DK, Zank, Serotta, RS, etc...?

I love this forum!

[djg]

So ... it seem to me that the most helpful answer comes from the door where the master ti designer/builder is standing, although I guess that fat robert is right too.

Catulle, I'd say that, this is another case where, if you're happy with the design and build, and the bike fits, you'll be happy with a bike made out of either material and that, barring tragedy, either should last for ages. I'd pick the source and the paint, and not sweat the alloying elements all that much.

FWIW, my 6/4 (main triangle, the rest is cf) Colnago is, after five years, free from any dents or dings or scratches in the metal pipes (and only minor paint wear). I think it's a great bike, but I wouldn't hesitate an instant over a Serotta or Specturm on account of an alloy preference--I believe that either TK or Serotta would build me a great bike if ... well, if I sent them a check.

[swoop]

So ... it seem to me that the most helpful answer comes from the door where the master ti designer/builder is standing, although I guess that fat robert is right too.

Catulle, I'd say that, this is another case where, if you're happy with the design and build, and the bike fits, you'll be happy with a bike made out of either material and that, barring tragedy, either should last for ages. I'd pick the source and the paint, and not sweat the alloying elements all that much.

FWIW, my 6/4 (main triangle, the rest is cf) Colnago is, after five years, free from any dents or dings or scratches in the metal pipes (and only minor paint wear). I think it's a great bike, but I wouldn't hesitate an instant over a Serotta or Specturm on account of an alloy preference--I believe that either TK or Serotta would build me a great bike if ... well, if I sent them a check.


i go a different direction. herein lies the exact reason i'd go with tk. he isn't a fit system or a new dude that does fits. he's a guy that can pick every tube and every angle and each choice has merit because he's lived it. it's the name on the frame and how many degrees of separation there aren't between you and him that make for a special experience in this age where mastery is a dying art and branding is the norm. if john franklin left eye moots were the dude doing the fitting i'd kick you in his direction too... if he raced... or even still rode hard.

quick, name 5 young framebuilders (i can only come up with a couple). where are all the young dudes?
:banana:

[Archibald]

i go a different direction. herein lies the exact reason i'd go with tk. he isn't a fit system or a new dude that does fits. he's a guy that can pick every tube and every angle and each choice has merit because he's lived it. it's the name on the frame and how many degrees of separation there aren't between you and him that make for a special experience in this age where mastery is a dying art and branding is the norm. if john franklin left eye moots were the dude doing the fitting i'd kick you in his direction too... if he raced... or even still rode hard.

quick, name 5 young framebuilders (i can only come up with a couple). where are all the young dudes?
:banana:What's your definition of young? Under 30? 30-ish?
Sacha White
Alexi Dold
Jason Grove
Curtis Inglis - Curtis is probably over 30 but he dresses young!
Maurico Rebolledo
Joseph Ahearne
Jay & Jeremy Sycip
Tony Pereira
Greg Townsend
Erik Noren
Jon Kendizera
Conor Buescher

That's just off the top of my head and I've forgotten more than I remembered. There are tons of young guys out there learning & mastering the craft. In 20 years you'll be saying some of their names like you do Ben Serotta, Richard Sachs, Peter Weigle, Bill Holland, Kent Eriksen and other greats in the industry today. Just look at the splash Sacha has made already!

:beer:

[swoop]

What's your definition of young? Under 30? 30-ish?
Sacha White
Alexi Dold
Jason Grove
Curtis Inglis - Curtis is probably over 30 but he dresses young!
Maurico Rebolledo
Joseph Ahearne
Jay & Jeremy Sycip
Tony Pereira
Greg Townsend
Erik Noren
Jon Kendizera
Conor Buescher

That's just off the top of my head and I've forgotten more than I remembered. There are tons of young guys out there learning & mastering the craft. In 20 years you'll be saying some of their names like you do Ben Serotta, Richard Sachs, Peter Weigle, Bill Holland, Kent Eriksen and other greats in the industry today. Just look at the splash Sacha has made already!

:beer:
well done. beer on me!
add aram at predator (he's 19)

[AgilisMerlin]

i go a different direction. herein lies the exact reason i'd go with tk. he isn't a fit system or a new dude that does fits. he's a guy that can pick every tube and every angle and each choice has merit because he's lived it. it's the name on the frame and how many degrees of separation there aren't between you and him that make for a special experience in this age where mastery is a dying art and branding is the norm. if john franklin left eye moots were the dude doing the fitting i'd kick you in his direction too... if he raced... or even still rode hard.

quick, name 5 young framebuilders (i can only come up with a couple). where are all the young dudes?
:banana:

http://static.flickr.com/37/175134980_f0bf5e958e.jpg?v=0

i don't know about 5 builders, but i do here this guy has 5 hearts in Texas. His chest jumps all over the place............... :p


Who woulda thunK ?

http://www.moyercycles.com/


AmerliN

[soulspinner]

See also Steve Potts...

[djg]

i go a different direction. herein lies the exact reason i'd go with tk. he isn't a fit system or a new dude that does fits. he's a guy that can pick every tube and every angle and each choice has merit because he's lived it. it's the name on the frame and how many degrees of separation there aren't between you and him that make for a special experience in this age where mastery is a dying art and branding is the norm. if john franklin left eye moots were the dude doing the fitting i'd kick you in his direction too... if he raced... or even still rode hard.

:banana:

Nothing wrong with that. But to get back to the tubing question: It seems to me that TK provided useful, distinct bits of information in response to Catulle's question. Beyond that, I stick with my story: if TK is the builder Catulle wants, he should talk to TK about a particular frame (for a particular rider, for intended purposes) and not stress too much (or at all) about the fact that somebody else might use pipes of a different alloy. I'd say the same thing if Catulle wanted to go to the larger operation of, say, Serotta for a legend (recognizing fully that it might not be the gestalt package somebody else is looking for and that, one might well think that the fit system really is the system as applied--that it depends on the particular person(s) using the tools).