Fixed gear audax bike (steel or Ti)

[belgiangoth]

Having ridden my pompino for 10ish years now, and having potentially sold one of my bikes, I can just about logic an upgrade. I’m after something that will take 28mm tyres and mudguards, not bothered about racks (won’t carry anything more than can ;be stored in a saddlebag), mostly for day rides (and fair weather commuting) but should be suitable for audaxes in the years to come.
I was thinking a steel frame from a local builder, probably threaded headset and quill stem; but then got to thinking that maybe I should consider something in titanium (if it exists) as this may be my only excuse to try titanium and maybe I should consider a future focused fork (with the possibility to follow advances with disk brakes and the like).
I would welcome thoughts and advice.

[fastpedaller]

Strangely I was going to recommend a Pompino. How about a Burls, I suspect they will be able to supply whatever you need.
http://burls.co.uk/

[belgiangoth]

My pompino is a great bike, takes 35mm studs for winter riding with mudguards and all. It is a bit overbuilt for a fast ride, 28mm tyres and a total of 70kg cargo.
Interesting to see that burls reckons 300g difference between Ti and steel...

[pwa]

My pompino is a great bike, takes 35mm studs for winter riding with mudguards and all. It is a bit overbuilt for a fast ride, 28mm tyres and a total of 70kg cargo.
Interesting to see that burls reckons 300g difference between Ti and steel...

An overbuilt frame can be a stiffer frame, which might actually make it more efficient when you get out of the saddle to get up a steep hill.

[belgiangoth]

True, but an overbuilt frame will be stiffer, so rougher, over flat rough surfaces, requiring wider tyres at lower pressure with associated energy costs.

[rmurphy195]

True, but an overbuilt frame will be stiffer, so rougher, over flat rough surfaces, requiring wider tyres at lower pressure with associated energy costs.

Wider tyres and lower pressures combined with a stiffer frame don't necessarily incur the penalty that most of us think these days, depends on the tyres I guess.

[hamster]

It's note even clear that a stiffer frame is more efficient anyway!
https://janheine.wordpress.com/2011/10/ ... stiffness/

The US Army did similar research and found that all the shaking of the body wasted more energy and furthermore added fatigue from bracing activity.

[531colin]

Titanium is about a third less dense than steel, but also about a third less stiff, gram for gram. So for frames that are comparable in design philosophy and intended purpose, the overall difference between the 2 materials is liable to be slight.
The stiffness of a tube is most greatly influenced by its diameter: stiffness increases by something like the square or the cube of the diameter, so if you double the diameter of your tube, it will be not be just twice as stiff, but somewhere around four to eight times as stiff. With steel, increasing frame tube diameter is limited by reducing wall thickness....lightweight steel tubesets are very easy to dent accidentally. Less dense titanium can make bigger diameter tubes where the wall thickness is enough to be reasonably dent-resistant (typically 0.9mm in plain-gauge tubing). The other "advantage" of titanium is that few designs increase the diameter of the chain- and seat-stays to account for the stiffness differences.....you can easily get a titanium frame with a stiff main triangle but compliant stays, this gives a ride which is efficient but provides some protection from road shocks.
Titanium stays are comparable in diameter with steel stays for 2 reasons......thicker stays look ugly, and there just isn't room between the chainwheel and tyre for a big tube. I would much rather make the chainstays a couple of centimetres longer and thread the un-dented tube between the chainwheel and tyre than have short chainstays where I need to flatten the tube (reducing its stiffness) in order to get clearance.

I have probably complicated the OPs day!

[belgiangoth]

Actually helpful as per usual Colin.

Current spanner in works is that Lee Cooper builds but does not design (which is a shame as I really need someone who can offer lots of advice) and it appears that my house wants to suck up all my money.