I have an older Schwinn touring frame that I like the ride and responsiveness of very much. It has Columbus Tenax tubing. I would like to buy or have built a titanium frame that feels the same but would have capability for wider tires and disc brakes.
How should I approach this? What would happen if the basic dimensions were recreated? How would titanium tube size be determined?
I realize that one answer is let the framebuilder decide but I would like to know more about the process ahead of time.
Thank you

There are two characteristics of the tubing that determine the stiffness/flexibility of a tube: wall thickness and diameter. Since the Young's modulus (measure of stiffness) is different for steels and titanium, typically the wall thickness of a titanium tube is greater than for a steel tube of the same diameter to achieve the same degree of 'stiffness'. This isn't as bad as it sounds, because the density of titanium is roughly half that of steel, so even with the thicker walled tubing the titanium tube will usually be lighter.

The best approach is to explain to the framebuilder what characteristics you're looking for in the frame and then leave it to him/her to decide what tubes to use and what geometry would be most effective in achieving the desired ride taking into account your size, weight, power output, and type of riding you do.

Just MHO.

Remember that a frame is not in isolation when riding the bike. So handling and flexing are also dealing with wheels and tires (and the other parts but the wheels/tires are the biggies). So when moving to new wheels and larger tires even the same frame will feel different when actually riding the complete bike. Andy.

The thing I found, over time, that I didn't like, was the feel of larger tubes in a frame. To be more specific, over sized steel tubing isn't really too bad. It isn't that much larger. However, some of the aluminum & CF bikes took/take it even further. The frames almost feel "in the way". Even the oversized steel frames I have feel a lot different. You may or may not like. Just worth noting.
The other point I would make is that it's tough to replicate the feel of another material. Having owned many different types of frames. They were all distinct, in feel. You can certainly go after a certain aspect, or characteristic. But often that will sacrifice elsewhere. I had a Merckx AXM, for example. I swore they built those frames to replicate the feel & response of a steel frame. Yet, in order to do that, it had a bulky, bulldogish feel to it. Materials just have inherent qualities to them.

I am going to reply and or edit my own post. I saw a lugged stainless steel bike on the Long Distance forum that seems like it would answer many concerns I have ----not having to deal with paint but getting modern spacing and a better choice of dropouts being two. Are the flex/stiffness/springiness of SS the same as that of carbon steel? Would it be easier to duplicate a frames characteristics in the same class of material?

I haven't read that thread, why not compare all three?
I'm intrigued

https://www.bikeforums.net/long-dista...-builders.html

DK; I highly agree with the responses the others who have already posted. IMHO, best of that advice is to get together with a quality builder and discuss what you are wanting in terms of the frame's characteristics. I am adding that much of how the final bike feels / rides / handles can be adjusted by choices of wheels lacing, tires, saddle, bars, your weight / riding style / strength, etc. I'll also add that I have had / come across a number of Ti-based bikes, but in the end I never felt that I wanted to keep any of them so I moved them on. YMMV, but that old Schwinn tourer may be the bike you really actually want to ride, perhaps with a tune-up and some freshening of the consumables. If you stay with it and add one of those full size posters of a shiny Ti racer to your wall...could be best of both worlds

Hope that helps
/K

Feel is pretty elusive, most attempts to duplicate it but just do whatever to make it that much better are doomed. You may get lucky, and you should be able to find a newer build that you will love, but duplicating feel is pretty tough.

If you want to be happy with a certain bike build, the recipe is as follows. Come up with some passionate characteristic that is easy to deliver, and that unless the bike is a complete dog, you will work your hardest to accept it. So let's say you never had a lugged bike with custom paint, and for years you have hungered after one. So you get some superlugged and painted bike, presumably well made anyway. Assume there is something about it that you don't find perfect, such that if it was a surly you would trade it off in within the next year or two. But in this case, it is the fulfilment of a dream, you would have to admit you had the wrong dream, and it is built by a legendary builder, what do you really know anyway? So you learn to love it.

Now if you ask for a bike that is very much like some obscure standard, then it isn't, game over. You have to leave enough room in your specs for self-deception.

If you are wanting a Ti bike with disc brakes, have a look at Volagi. I got the steel one - Ti is not in my budget - but they are very nice to ride.
https://www.volagi.com/purchase-a-viaje-ti/