pinholecam

I have ridden bikes built with all the materials, but even then, different bike types, geometries, design won't make it a final say in terms of one vs the other.

I feel that Ti has lost its luster and fallen behind Alu and Steel.
Alu and Steel has improved over the past 15yrs with triple butting, hydroform (for Alu), new alloys and treatments (for steel).
Their economies of scale has also not only pushed improvements but often done it at same/lower cost.
We now get the super light steel and alu bikes while Ti is largely stuck in the 6.8kg - 7.8kg mark.
Ti has largely remained 3/2.5 and 6/4 in terms of alloys for bikes and 6/4 has remained hard to work with (so most bikes are still 3/2.5).
Ti has also remained standard tubing (ie. cylindrical) and double butted save for a few custom makers who lathe down the tubing for triple butting.

That said, it does not rust, prices have come down for one and offers lighter weight for similar compliance to a standard steel bike (ie. not vs a more exotic one )
Personally, Ti is the material of choice and I can even design one to my needs and requirement for a relatively good price.

base2 

It seems good on paper.

The problem is a tube of identical dimensions frequently results in riding a spaghetti noodle.

The only way out of this is significantly larger tubes. This makes crankset/tire clearances & other conventional clearances/standards impossible with industry available conventional parts.

The oft employed "other" solution is significantly thicker (& otherwise unnecessarily heavier) tubes.

The result is not as much weight saved as otherwise could be, & difficult, expensive manufacture to do proper. All for not much tangible difference in function besides novelty. Granted, there isn't very many things more beautiful than a highly polished Ti frame...& that alone makes it worthy of owning.

Schwinnsta

If you want the same flex with Ti, the tube has to have a slightly larger diameter (thou it can be thinner). It is not a problem with clearances and standards. Aluminum has a even lower Modulus of elasticity and there seems to be no problem there. Aluminum would be the material of choice but for it not having a known fatigue limit. Because of that, manufactures have to use larger tubes than they would otherwise.

base2 

Well, I have been mistaken before.

I seem to remember a Ti mountain bike thread & chainstay/tire/crankarm clearance being an issue. The solution was some rework with thick, & tall rectangular tubes being used in that area, for a few inches of the chainstay, near the bottom bracket. The elasticity of Ti in thin gages of strength equivalent to some other materials made it such that things hit & rubbed in practice.

By extension, I can see other issues in frame design as well regarding harmonic oscillation (speed wobble,) & uninspiring cornering ability being concerns if only necessary strength to do the job were the only consideration to frame design.

Nowadays with 1.5 inch tapered headtubes, thru axles & the occassional 83mm bottom bracket, I have no doubt designs able to take advantage of Ti's unique properties may be ripe for a renaissance.

pinholecam

Certainly not the case as Ti tubing will still be thinner than the equivalent Alu tubing for the same build (and thicker than the steel one) - aiming for the same strength for the frame.
There are many examples of Ti gravel and MTB builds out there w/o any complaints of clearance issues.

One of the biggest advantages of Ti is the ability to easily find a custom builder and get what the rider is looking for.
Stiff BB area, compliant stays, short seatube to run a flexy carbon seatpost - Done!
Stiff but lighter than the equivalent steel frame - Done
Tire clearance, long wheelbase, bottle cage mounts galore? - No problem.


I designed a custom Ti all road bike to my fit, Ritchey breakaway system, 32mm tires on 700c and 38-42mm on 650b, reasonably lightweight at 7.8kg full build - all in a frame that won't rust as less worry of maintenance. Its not something thats easy to get off the shelf (except for the Ritchey Outback Carbon and steel 2020 ).

mlau

Hey Raxel,

Mind doing a write up of how you did this project?

I'd really love to try doing this, but I'm quite intimidated.
It'd be nice to have a "lifetime" brompton style folder.

-Matt

ps. As for my other "lifetime" bike, it's my xootr swift from dental school.

mlau

Sorry, I forgot about Raxel's other thread....that i bumped last night.