In need of some education on Ti tubing

[Clancy]

I am hoping to get a custom Ti frame made and in the search for that perfect ( for me ) frame, I have some questions on Ti tubing and shapes.

First, double butted tubing. How much weight difference is there? I understand when used, it's usually used for the major tubes, seat tube, top tube, down tube. True? Any advantage besides weight and is there a big weight difference?

Next, how is the ride of the bike "tuned"? By this I mean I have read where some companies state they tune the ride of the frame to the rider such as stiff vs flexible. I imagine this is done by different diameter tubing?

How do curved seat stays and chain stays affect the ride?

And what about different grades of Ti? From what I've read, US manufactured Ti is far superior to other countries but I understand there are different grades of Titanium?

Curious, what would a typical tube set cost to build a frame.

What else do I need to know? I've goggled but have only turned up very broad information, very little specific. Is there a web site that is a good resource?

Thanks!

[tv_vt]

I have come across some good info while searching online for stuff about Kent Eriksen frames. Any interview of his has some good info. Remember seeing one about butting of ti tubes and the reason why so few builders do it (he uses only straight gage). I've had ti frames from Dean, Merckx/Litespeed, and Hampsten, with the custom Hampsten being by far the best.

I think they do tune frames by tube diameter, and also by the choice of headtube you make - either an oversize 44cm that allows for a tapered steerer tube fork, or a slightly smaller one for a straight 1.125" fork.

Chainstays on ti frames have gotten larger over the years and make a frame a lot more responsive. They're either 7/8" or even 1" and most have some curve to them. There's a big difference in how my Merckx ti rides compared to the Hampsten, and I attribute some of that difference to the 7/8" chainstays on the Hampsten. Don't think a straight seatstay vs curved makes much difference. I have mixed feelings about the 'breezer' dropouts on the Hampsten, but I think they do help with ride quality and provide a solid welding surface for the stays. Some skewers don't work too well with them, though.

Everything these days is 3/2 ti, from what I have seen.

[benb]

I think these are all questions to ask a particular build/company you are interested in rather than asking here...

The cost of the tubeset is not real important for you unless you are building the frame yourself.

I'm shopping at the moment and I've been told you're talking maybe 1/2lb difference in the frame weight between butted and double butted and not much difference in ride quality assuming they select different tube thicknesses for the bike that is not butted within certain ranges.

Most bike are the 3AL/2.5V Ti alloy (~3% Aluminum/~2.5% Vanadium), Lynskey & Lightspeed have been the big names that have worked with the 6AL/4V variant. I think lots of others would say no advantage and possibly disadvantages to the 6/4 stuff. (Harder to work with, little benefit, destroys tools even faster, more likely to have a defect since harder to work with, etc..)

Having owned one Ti bike before and most likely buying another one I think the important thing is just who fits you to the bike & designs it more than anything else, no different than any other type of bike. My previous bike was double-butted and it rode great but didn't fit great. (It was a Serotta) It had curved chainstays & straight seatstays.

Another thing is dropouts, lots of manufacturers have different styles of dropouts.. my preference is for beefier ones that are not artistic. And I don't know who offers it today but Serotta had Ti dropouts on the F3 fork which meant you essentially never had to worry about damaging the fork dropouts.

[bikingshearer]

Most of these are questions best answered by your custom builder, especially the ones about "tuning" the bike to best suit your riding wishes. I suspect that"tuning" the ride of a Ti frame is done in much the same it is done for a steel frame - a combination of choice of tubes and geometry. But I'm not a builder, and I did not stay at a Holiday Inn Express last night, so I think you should seek out and communicate with several known builders of Ti goodies.

As for some of the more general questions, my Ti knowledge is not very extensive and probably at least somewhat out of date, but here goes as a starting point. Others will correct or add on as appropriate.

It used to be, and may still be, that there were two basic types of titanium used, 3/2.5 and 6/4. Titanium frames are actually made from an alloy that is mostly titanium but also has bits of other stuff too, just as different steels for different purposes have varying amounts of different other stuff in them; the numbers are percentages of two other elements in the mix, and I don't recall what they are. [Edit: benb answered this while I was still typing - thanks, benb.]

If I recall correctly, 3/2.5 can be extruded into seamless tubes. 6/4 cannot be extruded - it starts as sheets and has to be rolled or folded into shape and the seam welded. If a Ti frame has round tubes, odds are it is 3/2.5 alloy; if its tubes are teardrop or aero or otherwise not round, odds are it is 6/4. My memory banks also seem to recall that 6/4 frames are, on the whole, stiffer than more or less equivalent 3/2.5 frames, but (1) I could be very wrong about that and (2) tubing thicknesses and shapes and diameters, along with frame geometry likely have a big influence on this.

My understanding is that 6/4 is stronger and can be made into thinner-walled frames, and thus can be lighter than a 3/2.5 frame, but it is harder to work with. 3/2.5 makes for slightly thicker walls and thus slightly heavier frames, but is easier to work with. I have no clue about the effects of this on the ride of the final product: as to which makes more sense for you, that is a question for the builder.

I hope this helps you get started on what could be a very cool bike.

[berserk87]

My road rig is a Lynskey Helix. I like it for the most part. I get some lateral deflection in the bottom bracket area when I am cranking really hard, which leads to some occasional front derailleur rub in larger gears.

The selling point of the squared, helical tubing was that it added some rigidity, somewhere. I can't say I can tell a bit of difference versus any other Ti bike, but I have not ridden dozens of others for comparison, either.

The bottom line is that I dig the frame, but I can't tell if the odd tubing shapes are a real thing or just hype. I didn't impact my decision to buy the frame, really. I got a great deal on it and I wanted a Ti frame made in the US. This fit the bill as it was available and was within my budget.

[Mikej]

You ask the guy building your frame.

[velotel]

Call Kent and ask him; he's super easy to talk to and no problem giving you his thoughts on the subject. Phone number at kenteriksen.com (http://kenteriksen.com)

[soulspinner]

call kent and ask him; he's super easy to talk to and no problem giving you his thoughts on the subject. Phone number at kenteriksen.com (http://kenteriksen.com)

+1

[palincss]

It used to be, and may still be, that there were two basic types of titanium used, 3/2.5 and 6/4. Titanium frames are actually made from an alloy that is mostly titanium but also has bits of other stuff too, just as different steels for different purposes have varying amounts of different other stuff in them; the numbers are percentages of two other elements in the mix, and I don't recall what they are. [Edit: benb answered this while I was still typing - thanks, benb.]


Bicycles have also been made of unalloyed CP Titanium. Seven has a lot of excellent information about Titanium tubing on its web site here: http://www.sevencycles.com/buildingbike/techsupplement/ti.php

[eddief]

disassembled Russian submarines. My builder took those same tubes and built me the best bike I have ever owned. I hear those tubes are now becoming much harder to find, so try to find a builder with access to a good supply. When all else fails, you can't go wrong with a Firefly. All kidding aside, my bike has a butted down tube. Carver said I might save 4 oz or 112 grams by butting top and seat tubes too.

[jr59]

well I had Tom Kellogg make me 2 bikes that were very similar
. One had butted tubing and one str gauged. The double butted was lighter by about 1 lb. in a 62cm frame. The ride, I could not tell the difference. One had a steel fork and one had a C/F. I switched around forks and wheels back to back and really could not tell the difference, besides the fork. Both rode very close to the same.

Both had/have the curved rear stays, I was told that was just personal and wouldn't effect the ride one way or another. I believe Tom so that was that.

As far as stiffness goes, I'm pretty sure that is done with the oversizing of the tubes.

I love my spectrum, but I find/found myself riding steel bikes a LOT more, so I sold one of the Ti bikes. Kirk 007 seems to like it, as he should. It is a wonderful bike.

hope that helps

[Clancy]

You ask the guy building your frame.

What I'm planning on doing. But as with everything else, the better informed I am before I ask questions, the better I'll understand the answers and know what I want from the builder. Every builder has his preferences and biases.

[Louis]

Next, how is the ride of the bike "tuned"? By this I mean I have read where some companies state they tune the ride of the frame to the rider such as stiff vs flexible. I imagine this is done by different diameter tubing?

Assuming we're talking about a given material, which determines E (Young's modulus) and circular tubes, which defines how that material is shaped, then you're left with tube diameter and wall thickness. (Ignoring stuff like compact geometry vs horizontal top tube and other tricks like that.)

[avalonracing]

I've had ti road bikes from Seven, Litespeed and a late model Merlin CR designed by Tom Kellogg. They all had a VERY different feel ride to them despite similar geometry. If I were you I would contact Tom. He could custom design a Spectrum for you and have it built by Seven.

[marciero]

disassembled Russian submarines. My builder took those same tubes and built me the best bike I have ever owned. I hear those tubes are now becoming much harder to find, so try to find a builder with access to a good supply.

Nice play on the banter around guitar amplifier vacuum tubes, intentional or not.

[J. Anquetil]

For practical purposes, there are too many variables in using titanium tubes for a frame to get a simple, straight answer. There are at least ten different titanium alloy tubes for industrial use. For bicycles, the most popular by far is the 3/2.5 variation. 6/4 has more aluminum, is a bit lighter and stiffer than 3/2.5.

Then there is gauge and diameter, and then design. Butting a tube which is not even 1/4" thick will have an effect in the way the tube flexes and so forth but hardly any difference in weight. How much material can you shave off...? Moreover, you may use a tube of larger diameter yet thinner and save in weight and gain in stiffness.

Design: How you mix and match all eight tubes provides you with infinite possible results. So... I believe that you must start by knowing what you want and need. Then chose a builder and pray you get lucky. In the best of cases... you need to be lucky. And then there is the fork...

[RFC]

To your assertion that American fabricated Ti is vastly better, I have to take issue.

Russia has the world's largest titanium reserve and has made good use of it, including Ti MIGs and submarines.

One of the owners of Vassago is a neighbor of mine. Because of Russia's experience with Ti, he orders all of his Ti tubing from Russian sources to be cut and welded here.

I have a "few" Ti bikes. One of them is a mid 90's Titanium Red MTB, manufactured in the post Cold War MIG plants. It's beautifully done, nice welds and highly polished, with all sorts of little extras.

American Ti is just as good. That's one of the reasons I've always liked Lynskey era Litespeed. The Lynskey family already had decades of experience fabricating specialty Ti materials before they got into the bike business.

[oldpotatoe]

To your assertion that American fabricated Ti is vastly better, I have to take issue.

Russia has the world's largest titanium reserve and has made good use of it, including Ti MIGs and submarines.

One of the owners of Vassago is a neighbor of mine. Because of Russia's experience with Ti, he orders all of his Ti tubing from Russian sources to be cut and welded here.

I have a "few" Ti bikes. One of them is a mid 90's Titanium Red MTB, manufactured in the post Cold War MIG plants. It's beautifully done, nice welds and highly polished, with all sorts of little extras.

American Ti is just as good. That's one of the reasons I've always liked Lynskey era Litespeed. The Lynskey family already had decades of experience fabricating specialty Ti materials before they got into the bike business.

Know a guy who dealt with Russian and Chinese ti all the time. Sent some of each to a frame maker, which they analyzed. The 'off shore' tubes were indeed good, perfectly useable as a bike frame BUT were kinda 'dirty', as in some impurities that had an effect on welding. Plus, they spec-edthe tubes in terms of ID/OD, and they weren't particularly accurate. The $ wasn't so good that they decided to use it.

Yes, nobody else has made a double hulled sub out of titanium. Russia did, liquid lead cooled reactor..VERY fast, VERY noisy. The Alpha.