[Closed] Steel Vs Aluminium, can you tell the difference?

It really depends on the individual frame. I have ridden some aluminium bikes that are just as comfortable as steel, some steel bikes so harsh (Ragley/On One) that you could never ride more than an hour or so on.
The best steel bike I have ever ridden has been a Kinesis Decade Virsa. It definitely took some "buzz" out of the trail.
The best aluminium was a Pace RC 325.5.
I guess the most important factor is tyres/tyre pressure.

yes, no, maybe, it depends

Pick your answer to suit your view. Material is but one aspect in the makeup of the bike as a whole, but one aspect can either fade into the whole or end up defining it.

I can to look at them, i can tell the difference between my cotic and my old on one (both steel), but i think do a degree a skilled frame builder can tune in features with either material. I dont think most people could tell the material in a blind test, which would clearly be very dangerous. One of the mags did a charge ti vs steel test a few years ago, with the ti painted to look the same, same parts etc. The conclusion was i think most of the time most people coudldnt tell, but if you want to get something bling and you can afford it why the hell not. We can kid ourselves a lot when we are spending lots of money on bike bling, but its ultimately about what you want and you can afford. They're all pretty good these days, but some dont suit our self-image, wallet or plain dont fit.

yes, no, maybe, it depends

This.

But while there are comfy alu frames out there, the old cliches still apply when you aggregate things, IMO.

I'm not saying that this is the case with bike frame material but there are times where people want to know the ins and outs of something so much that they blind themselves to the reality of the situation.

I was rebuilding my VW Corrado and wanted to change the rear axle bushes. Virtually all the enthusiasts I asked were adamant that standard ones were the ones to get as some genius at VW designed them to make the back end steer to help you through corners. They said that they could feel it happening and wasn't it amazing..

This sounded like bollocks to me and, looking at the bushes in person, I couldn't see how it would be the case. It turns out that actually the opposite is true. VW engineers worked very hard to eliminate rear-steer and these bushes were made the way they were to stop it. However, marketing got a sniff of this rear steering and turned it around because they though it would sell (Honda Prelude 4WS had just come out).

Even 20 years later everyone was so convinced by the idea that they put aside objective reason and actually [i]felt[/i] dynamic nuances that weren't really there.

My old Kinesis racelight (aluminium) was quick but so, so harsh. Bought a 631 frame (Hewitt Chiltern audax) & transferred all the parts lock, stock. So only changes are material of frame (kept the Kinesis fork) & very minor differences in geometry. Difference is night and day, so much less buzz coming from the road and bumps gently - rather than crashing harshly - through potholes and the like.

It would be entirely possible for someone with some engineering testing knowledge and equipment to build a rig that would enable actual measurements of frame deflection under load, transmission of vibration etc. that could put all this myth and magic to bed. If there was real meaningful 'suspension' built into a rigid frame then you could compress it with your bodyweight and see the frame flex - but can you?

If, for example, a journalistic enterprise was interested in doing this it would make for some great reading. What do you say Singletrack?

Cognitive bias innit. See the wacky world of the audiophile for fine examples on this.

I can't tell at all. Added carbon bars and post and couldn't tell between that or my Alu ones either.

There's a whole lot of cushion of air absorbing bumps and flex etc.

If there was real meaningful 'suspension' built into a rigid frame then you could compress it with your bodyweight and see the frame flex - but can you?

I'd expect it's more about the transmission (or not) of vibrations, which you did allude to in the first part of your post.

Cognitive bias innit. See the wacky world of the audiophile for fine examples on this.

Seems a bit contrarian to deny the existence of widely observed ride qualities for steel vs alu vs carbon.

Personally I was happy to go over to an alu HT, but grudgingly had to admit that steel was more comfy.

Easiest thing woudl be to get two frames similar or identical, but with different materials. Get a rider, blindfold him, put one of those old school rain capes on him, then get him on a bike and remove the blindfolds. The cape will prevent him seeing which bike is which. Then ride along a series of test tracks at different speeds, see if he can tell.

Or use an accelerometer on a normal bike ride. I wonder if a phone app could do it?

I'd expect it's more about the transmission (or not) of vibrations, which you did allude to in the first part of your post.

yup, that ought to be pretty easy to measure - sensors on the contact points, apply vibration / forces to the axles & measure the outcome. There must be someone engineering-y on this forum who could figure this out...

yup, that ought to be pretty easy to measure - sensors on the contact points, apply vibration / forces to the axles & measure the outcome.

It's a great idea, although I'm sure people would find fault with the test if they didn't like the result.

yes, no, maybe, it depends

I've ridden Alu that is pretty comfy and compliant, but also ridden steel that is stiff as hell, and vice versa.

It would be entirely possible for someone with some engineering testing knowledge and equipment to build a rig that would enable actual measurements of frame deflection under load, transmission of vibration etc. that could put all this myth and magic to bed.

They did that a while ago for cranks in one of the mags (not the vibration thing, just deflection) - if I remember correctly the renowned noodly feeling cranks deflected a tiny amount more than the mega stiff ones, it was so minor difference (0.4mm seems to ring a bell) that you'd never tell the difference in real life. Despite people saying it was like night and day.

I suspect it'd be the same for frames. I'm a luddite and couldn't tell the difference between titanium and alloy but they were so many other factors like grips, tyres etc. I'm not sure you could do it without making up identical bikes anyway. You must be talking a tiny amount of movement and as pointed out a gas pipe steel frame could be worse than a top notch alloy one.

https://www.materialsciencescorp.com/products

we used to do some work with this firm quietsteel what a buzzword eh?

It would be entirely possible for someone with some engineering testing knowledge and equipment to build a rig that would enable actual measurements of frame deflection under load,

This isn't that what test houses would be doing as a matter of course to demonstrate compliance with EN ISO 4210, (or previously EN 14766)?

The real question is what would the average consumer (and cycling press) make of measured deflection figures for a given bike frame? Would it mean anything to most people?

I can certainly tell the difference, along with different wheels (XC>Enduro) and fork stantion size (32>35mm). I can't tell the difference between cranks or stem/bars size though (i.e.- 31.8>35mm).

The old steel ones were more forgiving than alu.

[quote=joemmo ]It would be entirely possible for someone with some engineering testing knowledge and equipment to build a rig that would enable actual measurements of frame deflection under load, transmission of vibration etc. that could put all this myth and magic to bed.

It's been done. It hasn't changed the opinions of anybody who can "feel" the difference. Regarding transmission and damping of vibration, metal frames don't provide any significant damping (not compared to the other things attached to them like tyres and humans) and it doesn't vary much between different metals, transmission of vibration is closely related to stiffness.

[quote=chakaping ]

Cognitive bias innit. See the wacky world of the audiophile for fine examples on this.

In the same way differences in audio equipment (which can't be detected by instruments) have been widely observed? Lots of people experiencing the same cognitive bias doesn't mean it's not cognitive bias.

[quote=molgrips ]Easiest thing woudl be to get two frames similar or identical, but with different materials. Get a rider, blindfold him, put one of those old school rain capes on him, then get him on a bike and remove the blindfolds. The cape will prevent him seeing which bike is which. Then ride along a series of test tracks at different speeds, see if he can tell.

The trouble is that still wouldn't provide a true blind test - at least not of the "ride quality" which is what people seem interested in. Because it is possible for the average human to tell the difference between different frames (and different materials) from the amount of lateral flex. Which unlike vertical flex there is a significant amount of and significant variation in - it's just that whilst it doesn't contribute to comfort, riders brains tend to interpret more flex as more comfort.

Nothing to do with cognitive bias, everything to do with tube diameter.

Modern light steels are stiff, but come in larger diameter tubes.

I've said it many times:
Handling = geometry
Stiffness = tube diameter
Weight = material

You only have to stand up on a thin tubed steel bike and look at the bottom bracket move. Compare this deflection with an alloy or carbon bike, or even a 953 steel bike.

In the same way differences in audio equipment (which can't be detected by instruments) have been widely observed? Lots of people experiencing the same cognitive bias doesn't mean it's not cognitive bias.

But people saying they can hear the difference with a £500 audio cable are in a minority, whereas there is a general consensus on the prevailing ride qualities of steel vs alu.

[quote=TiRed ]You only have to stand up on a thin tubed steel bike and look at the bottom bracket move. Compare this deflection with an alloy or carbon bike, or even a 953 steel bike.

Nice demonstration of lateral stiffness, which varies between bikes. Have you got a method of showing the difference in vertical stiffness?

[quote=chakaping ]But people saying they can hear the difference with a £500 audio cable are in a minority

Only because a minority of people own £500 audio cables - I bet the majority of people who own them can hear the difference.

whereas there is a general consensus on the prevailing ride qualities of steel vs alu.

That's because it's common perceived wisdom, which is often (not always) complete rubbish. People read something in a magazine 20 years ago and that becomes immutable fact.

Carbon snaps, aluminium is stiff etc etc.

Only because a minority of people own £500 audio cables - I bet the majority of people who own them can hear the difference.

And I bet most of their friends nod politely, but then twirl their finger around next to their ear when they're not looking.

Yes - Steel is heavy and dull whilst aluminium is light and lively.

That's because it's common perceived wisdom, which is often (not always) complete rubbish.

You mean received wisdom. And there's an element of that.

But there are also many of us who ride a lot of different bikes and are capable of gathering our own empirical evidence.

Just as there are others willing to argue black is white on the internet because they have a weird contrary streak to their personality.

But there are also many of us who ride a lot of different bikes and are capable of gathering our own empirical evidence.

Rather difficult to tell the difference though isn't it? 🙂

If the OP is buying a bike then ride it and see what you like. If he's just posting a discussion, then this is part of it 🙂

Nice demonstration of lateral stiffness, which varies between bikes. Have you got a method of showing the difference in vertical stiffness?

There really isn't any 😉 Tyres have a much bigger effect.

A blinded test is very hard to conduct, closest thing is steel and titanium with the same geometry and tube diameters - I think that's been done and showed no effect. Carbon and alloy is also possible, but I can't really sense any difference between my £150 Alloy and £2150 Carbon SL Defy frames (other than weight, obviously).

Riding my 2Souls QuarterHorse on a bumpy trail ,I became aware of just how smooth it was over rough ground.Then the penny dropped,my Bikeyoke Revive had got a bit of air in it.Giving me about 10 mm of suspension .Fixed it there & then & the ride was back to normal.So I think the components & pressures we use do such a good job of masking what is going on with the frame,it is almost impossible to tell.The good news is that with the wheel & tire sizes available today,we can choose any frame material & make it behave how we want it to.Just need to find out how to get the air back in my dropper post!

empirical evidence.

TBH I've not seen much "empirical evidence" to support either viewpoint, but we're talking about a qualitative thing, the perception of a bikes ride; one person's [i]"Compliant"[/i] is another person's [i]"Noodley"[/i] one person's [i]"Harsh"[/i] is another's [i]"Responsive"[/i] and so on...
I'll accept that differences in ride between bikes can be felt, but I'm sure they're often wrongly attributed solely to the frame material when it's only part of the equation.

The frame is a single component, upon which a number of others are mounted, and while the load path between the rider and the tyre's contact path always involves the frame, there will be at least three other major components involved, each of which will make their own contribution to the bikes overall [i]"ride quality"[/i]...

joemmo - Member
It would be entirely possible for someone with some engineering testing knowledge and equipment to build a rig that would enable actual measurements of frame deflection under load, transmission of vibration etc. that could put all this myth and magic to bed. If there was real meaningful 'suspension' built into a rigid frame then you could compress it with your bodyweight and see the frame flex - but can you?

If, for example, a journalistic enterprise was interested in doing this it would make for some great reading. What do you say Singletrack?

Mick Burrow's book on bike design includes some testing he did to determine the flex on a set of forks. The answer was SFA compared to how much the tyre deformed - even on a flat surface (over small bumps the tyre will deform even more)

But don't let the facts distract you from your princess and the pea fantasies. You can tell the difference from about 1kg extra weight and some "zing" (lateral/torsional flex). The lateral flex might help comfort in some ways I suppose, but adding a pivot or two with a spring and damper would help more.

It would be entirely possible for someone with some engineering testing knowledge and equipment to build a rig that would enable actual measurements of frame deflection under load, transmission of vibration etc. that could put all this myth and magic to bed. If there was real meaningful 'suspension' built into a rigid frame then you could compress it with your bodyweight and see the frame flex - but can you?

If, for example, a journalistic enterprise was interested in doing this it would make for some great reading. What do you say Singletrack?

You've obviously never picked up a copy of "Das Mountainbike" of some other generic German bike mag. Most of their bike testing seems to take place within the confines of a laboratory where frames are weighed and twisted.

Steifigkeit gewinnt immer.... The stiffer the better it would seem.

My Sanderson Breath replaced my crash damaged Scott Scale. The difference was night and day. The Sanderson seemed to absorb much more of the "chatter" when descending,was much comfier on longer sit down rides.

Then changed to a DB Alpine. That felt dead for most of the time until you really ragged the #*\k out of it.

Friend had a 456 and that made me think that the Alpine was more compliant/alive/insert cliché here/livelier.
He now has a Stanton which reminds me more of my Alpine.

Another friend has a Liteville 101 which feels harsh. However, it weighs naff all....!

I use a magnet.