[xpe]

> Use larger diameter tubular components - Strength goes up as the cube of the diameter so unless there are geometric constraints, use larger diameter tubes with thinner walls to get a lighter structure with increased strength and stiffness.

This trend has continued -- it is very noticeable in road and mountain bikes.

But this trades off against impact resistance, aerodynamics, and the can-it-fit-between-your-legs-metric.

[donavanm]

If youre thinking modern carbon frames most of that is actually driven by design for manufacturability, not strength/weight/performance optimizations per se. Off the top of my head:

Frame “tube” dimensions driven by layup mold & mandrel/bladder requirements to minimize tooling and layup time

Press fit to reduce inserts and post mold operations with a “simpler” molded interface

Flat mount brakes to simplify mold shape and support simpler insert components

UDH and direct mount again the simplicity of molded in shape, minimal inserts, reduced post mold operations.

“Modern” UDH hangers move threaded components off the frame. much simpler than the old syntace style which need both precise thread alignment and/or frame tooling operations and/or additional inserts.

You could probably throw head tubes in here too; split races to avoid reaming, molded bare pseudo-press fit “cups”, and the absolute ridiculous sizes like IS47 and larger.

Many/most of those only help manufacturing costs for major frame factories. And are middling to suck for other materials and small volumes. Ex steel flatmount and IS47 is an absolute joke.

[ginko]

My main gripe with those large diameter tube frames is that they're just ugly.

[loeg]

Taste is personal; and of course, you can still buy skinny-tube steel frame bikes, with probably more options available than at any other time in history.