Now I think people should buy whatever bike they want, or whatever gets you out riding. One point I will agree with is that carbon, titanium, and steel bikes can all be aesthetically lovely in ways that alu bikes are usually not.
this is the key point. The cycling industry is a fashion industry. If it wasn't stuff wouldn't be sold in different colours each year People will generally make aesthetic choices first then cherrypick factoids from the marketing bumpf to make those choices seem somehow engineering or performance based, but they'll do that after they've made their choice based on looks. You'll see more commentary on this forum about how any bike / frame / component looks than anything else
A lot of the resistance to change in the ever evolving 'standards' grumbles I think is rooted in worry that a new diameter or a new set of angles is going to make your current bike look unfashionable.
i have a ti mtb that is very harsh and stiff.
itsmuch more about the design than the materialsÂ
What happened to the OP? He wanted to discuss this then buggers off after the original post and one comment.
What happened to the OP? He wanted to discuss this then buggers off after the original post and one comment.
By "bugger off" you mean not replying for one day while replies are still rolling in and I'm having a busy Sunday? Not sure what your problem is.
Apologies OP but it is just unusual to start a fairly detailed discussion post and then not communicate thereafter.
From the handful of users I know you've drawn in people from bike manufacturers, frame designers, framebuilders, engineers and physicists. But I'm still not sure if you've got more than opinion and anecdote.
Apologies OP but it is just unusual to start a fairly detailed discussion post and then not communicate thereafter.
Which might be fair to say if I hadn't replied for a week. This is a forum not a live chat.
From the handful of users I know you've drawn in people from bike manufacturers, frame designers, framebuilders, engineers and physicists. But I'm still not sure if you've got more than opinion and anecdote.
Yes and I like the range of perspectives from people with far more experience than me. You seem to assume that I made up my mind after reading that cyclingabout article. Many commentors have brought up flaws or other points that article and my first post has overlooked. Which I have enjoyed reading, what I don't enjoy is meta commentary that brings no substance to the discussion.
I think one reason steel frames can feel comfier than aluminium frames, even when built to have similar stiffness, is that the denser material lowers the resonant frequencies and takes those vibrations into a range that are generally less unpleasant for humans.
This and the sound fit with my experience. Steel and Al hardtails on rough ground may be objectively the same stiffness; however, the Al is noisy while the steel is silent. Perhaps the bigger internal volume of the Al, or the different density. Either way, I perceive the steel as being different, and, as mentioned, in some of the articles linked above, we humans are not great at correctly identifying what the actual difference is. Also, I like steel frames.😀
The main theme I'm seeing from the responses is that it's not about the frame material, it's how its used. Interesting to hear many reports of bikes whose ride quality does not match the stereotype, like uncomfortable steel bikes.
That suggests for the next bike I should look for a specific frame which everyone loves the ride quality of, and is remarkable in its design/QA/aesthetics, rather than caring about the material.
I also learned:
- Comfort is about torsional compliance not just horizontal compliance
- The Pantani record does not tell us much since he was riding a very unique alu frame
- A Silca bike tester confirms that the placebo effect is huge for frames
- A downside of aluminium is that frames have a finite lifespan and failure can be sudden
The main theme I'm seeing from the responses is that it's not about the frame material, it's how its used.
Absolutely. But how the material can/might/should/could/will be used depends on its characteristics.
"Steel and Al hardtails on rough ground may be objectively the same stiffness; however, the Al is noisy while the steel is silent. Perhaps the bigger internal volume of the Al, or the different density."
Aha, I think you've hit upon something there!
The steel tubes are denser and slimmer - this lowers their resonant frequencies according. The air chambers within the steel frame are smaller which raises their resonant frequencies (they'll exhibit these as a mix of half and quarter wave resonators and helmholtz resonators). If you think of the internal volume compared to an acoustic guitar body it's a small volume. I suspect that with a steel frame the resonant frequencies in the metal are a long way from the resonant frequencies in the internal air, whilst in an aluminium frame the resonances are closer so they're more easily excited. And that's that annoying buzz.
Also the bigger and less dense aluminium tubes will emit more sound due to the greater radiating area and the reduced acoustic impedance mismatch vs steel. A quieter bike simply feels better downhill, you hear more of what your tyres are telling you about the ground.
Apologies OP but it is just unusual to start a fairly detailed discussion post and then not communicate thereafter.
Better than the alternative;
Ask a "question"
Belligerently argue with absolutely every answer because what you really wanted was validation of your starting premise, not alternative viewpoints.
The steel tubes are denser and slimmer - this lowers their resonant frequencies according.
Surely this comes back to what Cy said about the Rocket, on a bike your design is already size constrained, your seat-tube and stays are always near enough the same sizes regardless of material because that's what fits. Â
Comparisons to sound waves isn't valid I don't think. My SS'ed (alu) HT has a chain tensioner on the BB which makes a noise (I'm guessing a resonant frequency of the downtube must be close to the chain passing over it) yet it's actually possibly the most comfortable HT I've had.
Secondly, and related, tubes aren't absorbing these impacts/vibrations in compression, they are WAY too stiff for that. They do it by deflecting, so anything that bends them or makes them thinner in the direction you want to deflect them helps. Traditionally that would mean hourglass or wishbone stays, now it's more likley a flat top tube.
The Pantani record does not tell us much since he was riding a very unique alu frame doped up to the eyeballs?
FTFY ;o)
I'd say steel over Alu every time, if only on silence/longevity/reparability grounds. The weight isn't really important unless you need to save the grams for racing.Â
I wouldn't choose to have an alloy or steel frame at all and I've had quite a few of both. The only really well riding (handling/comfort) steel frame I've had was an Independent Fabrication and the only alloy one (that again had both handling and comfort) was a Klein. I've had steel and alloy bikes (Santa Cruz, Salsa, Orange, Genesis, etc) that all handled well, but weren't stand out for "feel".  The Klein and the IF both had that unique combination of material and tube shape/size, possibly suggesting that design which incorporates the junctions, tube cross sections and material performance in the centre and the joints is the key. Â
Like, just flattening and ovalising a tube changes its stiffness in different directions
You confirmed my point. That all things being equal (i.e., geometry), stiffness can be changed by tube cross section. My Enigma has an ovalised oversize down tube, for example. But i don't have a round version Echo to compare. I'd summarise Ti by: If you like how steel handles, you'll really like Ti. If you don't (more flexible frame), you'll prefer alloy and carbon. The oversize carbon really stiffens up a frame and delivers low weight without trying.
But weight balance is geometry, as is fork rake and trail, wheelbase, BB drop, all solved problems and largely not deviating much from 73 degrees parallel on the road (a few tweaks of half a degree on seat and head tube and sometimes longer seatstays). As I said, I have a bargain basement alloy, and a pro-level carbon Defy SL.They really do ride the same (same contact points and stem, same geometry, 10x different price point). I am under no illusions that my Charge Freezer Ti would handle the same as the steel version, and that my Brompton T-Line handles the same as an P-line.
There are many choices in frame design, but I think my simple reduction holds. Go and ride a Vitus 979 (*swoon*) or an original Carbon Giant Cadex 980. Nobody was claiming stiffness for Aluminium or Carbon, it was all about frame weight for first interations of new fangled materials.
