Is this good?

[Nigeyy]

Oh dear, not this old `chestnut of steel vs. alu again! However, I can truthfully say I have the answer about this argument. Without a doubt, the best material to make a frame from is the material that provides adequate safety, reliability, longevity, performance, fit and comfort.

And.... err... to some people that's steel, alu, carbon fibre, etc....

Just some points of interest (I've ridden quite a few bikes):
1. I feel very comfortable in saying the harshest bike I've ever ridden was an old steel Fuji. It was nasty!
2. Smoothest bike I've ridden? Honestly, don't laugh, but a Cannondale CAAD 4. Done quite a few centuries on that with complete comfort.

Course, I don't equate steel=discomfort, alu=comfort from this experience, just that different bikes with different designs, with different components, with different riders with different riding styles for different ride types feel... well... different.

And I can't post without saying that a problem I suspect strongly with frame material evangelists has to surely be a self fulfilling prophecy? Since someone may say "*insert frame material of choice here* is the best" surely they will have a predilection to prefer that material knowing they are riding a frame made of that material? From a scientific point of view: when has someone blind tested a frame on a bike? I would love to see the results of that!

In interests of full disclosure, I should add I really don't care a primate's relative whether a bike is steel or alu, just that I like the complete bike and how it feels.

 

[User482]

Oh dear, not this old `chestnut of steel vs. alu again! However, I can truthfully say I have the answer about this argument. Without a doubt, the best material to make a frame from is the material that provides adequate safety, reliability, longevity, performance, fit and comfort.

And.... err... to some people that's steel, alu, carbon fibre, etc....

Just some points of interest (I've ridden quite a few bikes):
1. I feel very comfortable in saying the harshest bike I've ever ridden was an old steel Fuji. It was nasty!
2. Smoothest bike I've ridden? Honestly, don't laugh, but a Cannondale CAAD 4. Done quite a few centuries on that with complete comfort.

Course, I don't equate steel=discomfort, alu=comfort from this experience, just that different bikes with different designs, with different components, with different riders with different riding styles for different ride types feel... well... different.

And I can't post without saying that a problem I suspect strongly with frame material evangelists has to surely be a self fulfilling prophecy? Since someone may say "*insert frame material of choice here* is the best" surely they will have a predilection to prefer that material knowing they are riding a frame made of that material? From a scientific point of view: when has someone blind tested a frame on a bike? I would love to see the results of that!

In interests of full disclosure, I should add I really don't care a primate's relative whether a bike is steel or alu, just that I like the complete bike and how it feels.

And likewise I have done a few centuries on carbon fibre and alu frame bikes. But my view is that the advantages of steel over alu are the properties that I look for in a touring bike. For road racing or suspension mountain bikes, steel would probably not be my preference as I think that other materials are better suited to these applications.

 

[ChrisKH]

It's entirely possible Kathy has decided to top herself after reading this lot.

 

[Fab Foodie]

It's entirely possible Kathy has decided to top herself after reading this lot.

Or bought a car...

 

[Chris James]

It will always fail, given infinite time, yes. You appear to have extrapolated the notion that because of (a) only a limited amount of flexing can occur before it breaks, and ( some flexing always does occur, no matter how significant, then a frame will therefore ALWAYS break. ...... It could be that it takes thousands of years of hard riding for it to reach the point of breaking. You appear to be then using this as leverage of your argument that steel frames are therefore better.

And, furthermore, if you're such an expert on materials science, explain this to me on a physical level: how, after a year of riding, are the molecules in an aluminium frame arranged any differently to when new, in such a way that makes the frame more likely to break?

Hi Bonj, you are appear to be attributing opinions to me that I don't have! In particular I have never argued that steel frames are better. There are advantages and disadvantegs to all materials and the design and fabrication play a very important part too.

But bear in mind that this whole exchange started because you said that the mixte frame was not much use becasue it was steel. So it is you who is saying steel in unsuitable rather than me dismissing aluminium alloys!

First thing, yes aluminium will always fail - in finite, not infinite time. But how long that period is depends on how much stress the material experiences - eg is a function of the wall thickness and diameter. However, aluminium's main advantage over steel is that is has a lower density (with albeit lower strength too) and if you are required to make the frame very hefty to prevent it failing then this advantage is negated.

As I stated in my original post, you can make a frame out of anything. But some will last longer than others. Typically commercially produced aluminium frames will be slightly lighter than steel ones, but will not last as long. If you plan on changing your frame every few years this doesn't matter. However, in order to get a decent working life from an aluminium alloy frame it will always be stiffer than a similar weight steel frame so the ride will be different. This often unacceptable level of stiffness is the reason why most aluminium alloy frames are kitted with carbon fibre forks, although the short wheelbase loved by roadies also contribute to this.

There is a piece on this on Wikipedia that appears reasonable. If you look at the section entitled Design against fatigue you will see that steel frames are designed to follow method 1 (infinite life) and aluminium alloy frames method 2 (safe life design).

http://en.wikipedia.org/wiki/Fatigue_(material)

The next link covers your question about the microstructural changes experienced as a material is worked. Tony has covered this point anyway in a more general way.

http://en.wikipedia.org/wiki/Dislocation

Finally, I am not an expert on material science and haven't claimed to be one but I do have a B.Eng. (2.1 not third!) in Mechanical Engineering - funnily enough from the University of your current home town - specialising in fracture mechanics and also an M.Sc. in Corrosion Science and Engineering so have quite a bit of knowledge in this field.

 

[Nigeyy]

You pays your money, you takes your choice. For me personally (touring in western countries and not being a performance athelete!), there just aren't any overriding advantages to steel or alu with a touring bike or road bike, given the big picture of the complete bike. Too many different designs and components.

I do have a steel tourer, and a steel road bike and an alu road bike though. But that was more a function of liking the bike and costs involved than a preference for either material. It's whatever you like as a rider.

And likewise I have done a few centuries on carbon fibre and alu frame bikes. But my view is that the advantages of steel over alu are the properties that I look for in a touring bike. For road racing or suspension mountain bikes, steel would probably not be my preference as I think that other materials are better suited to these applications.

 

[Bonj Hovi]

Finally, I am not an expert on material science and haven't claimed to be one but I do have a B.Eng. (2.1 not third!) in Mechanical Engineering - funnily enough from the University of your current home town - specialising in fracture mechanics and also an M.Sc. in Corrosion Science and Engineering so have quite a bit of knowledge in this field.

Bonj is an expert at attributing false claims to a range of posters and ignoring advice from better informed folk. Don't think for one minute that your qualifications count for anything - he's dismissed other folks' qualifications and experience out of hand and ploughed a lonely furrow to demonstrate that aluminium is a material with mechanical properties that make it the material of choice for cycle frames.

He's ignored the fact that aluminium is not used as a pure metal in bike frames.
He's ignored the mechanical properties of aluminium that are modified by alloying.
He's ignored the fact that load bearing aluminium structures have a finite life.
He's ignored the fact that work hardening of aluminium alloys takes placed when flexed.
He's ignored the fact that aluminium framed bikes do flex.
He's ignored the fact that the metallurgy of steel has changed for the better since the frame faliures in the Tour de France.
He's ignored the fact that for the intended purpose the steel mixte framed bike purchased by the original poster perfectly suited suited.
He's ignored the fact that when aluminium frames fail on tour it's generally game over.

It is good of you to take the time to dismantle the falsehoods propagated by Bonj. Sadly it's unlikely to persuade Bonj that his ingnorance of the material world is in need of correction.

The gulf between the quality of your exposition vs that of Bonj's suggests that even a third is, perhaps, an optimistic claim on Bonj's part. I know that the contents of the Physics A-level has been considerably slimmed down over the years but I doubt that stress, strain, bulk modulus, and elastic limits etc has been removed. There's little in Bonj's rants to suggest that he's progressed beyond a low grade A-level pass in his claimed sphere of knowledge.

Bonj's grasp of materials science would be further improved if he also read:

• Structures: Or Why Things Don't Fall Down
• The New Science of Strong Materials: Or Why You Don't Fall Through the Floor

Both books are by Professor J.E. Gordon and have stood the test of time as informative books for undergraduate mechanical engineers, metallurgists and materials scientists.

 

[bonj2]

Hi Bonj, you are appear to be attributing opinions to me that I don't have! In particular I have never argued that steel frames are better. There are advantages and disadvantegs to all materials and the design and fabrication play a very important part too.

But bear in mind that this whole exchange started because you said that the mixte frame was not much use becasue it was steel. So it is you who is saying steel in unsuitable rather than me dismissing aluminium alloys!

No, i said it was a GWC. I dont' think i used the words 'useless' or 'unsuitable' - I just said I think there's better options.
It's heavier than the OP needs, not least because it's made out of steel, but because it's got tubes in places it shouldn't need them.

First thing, yes aluminium will always fail - in finite, not infinite time. But how long that period is depends on how much stress the material experiences - eg is a function of the wall thickness and diameter. However, aluminium's main advantage over steel is that is has a lower density (with albeit lower strength too) and if you are required to make the frame very hefty to prevent it failing then this advantage is negated.

you don't have to make it VERY hefty - just slightly heftier, but usually it's still somewhat lighter - otherwise why would they make frames out of aluminium?

As I stated in my original post, you can make a frame out of anything. But some will last longer than others. Typically commercially produced aluminium frames will be slightly lighter than steel ones, but will not last as long. If you plan on changing your frame every few years this doesn't matter. However, in order to get a decent working life from an aluminium alloy frame it will always be stiffer than a similar weight steel frame so the ride will be different. This often unacceptable level of stiffness is the reason why most aluminium alloy frames are kitted with carbon fibre forks, although the short wheelbase loved by roadies also contribute to this.

You mark yourself out as a steelophile because with every successive post, you appear to be succumbing to the addiction of needing to reinforce the notion that 'an aluminium frame will break one day', and having to give yourself the additional fix of pretending this time to fail will be 'only a few years'. You obviously own a steel bike, and are conscious of the fact an aluminium one would be lighter, so whenever you're lugging the thing around rather than consider getting an aluminium one instead, you obviously need to imagine yourself coming across me walking along carrying my broken frame, cursing its manufacturers for making it out of aluminium, while you ride off into the sunset chuckling smugly on your invincible steel one.
You just don't see, hear of, or see the results of, enough incidents involving breakages of aluminium frames for this to ring even remotely true I'm afraid Chris - unless, like I say - a 'few' years is a few hundred or thousands.
e.g. cassettes wear out - the chain gradually grinds the metal of the teeth away - you always get posts on here about that. There's other common wear and tear things that crop up time and time again. But I can't remember when the last time I saw a post about someone's aluminium frame breaking was.

 

[rich p]

I just pop in here every now and again to make sure the hasn't ended. You lot will pop out from the undergrowth in 20 years time and find that they've discovered a new bike frame material that surpasseth all others!

 

[Abitrary]

Planet X are now doing cheap titanium frames

 

[vernon]

Planet X are now doing cheap titanium frames

And Spa cycles will fit you out with a complete steel frame touring bike, luggage and lighting for less than the price of the 'cheap' titanium frame. You mihgt even get a tent thrown in too!

 

[Abitrary]

And Spa cycles will fit you out with a complete steel frame touring bike, luggage and lighting for less than the price of the 'cheap' titanium frame. You mihgt even get a tent thrown in too!

They're not cheap ones... they're made by the original litespeed people.

I was actually thinking about a steel audax frame type thing, but now that the mail order companies are doing it, I might just bypass steel and move straight up to titanium.

 

[Chris James]

No, i said it was a GWC. I dont' think i used the words 'useless' or 'unsuitable'

I assumed that 'genuine work of crapola' meant that you dind't think it was well suited.

You mark yourself out as a steelophile because with every successive post, you appear to be succumbing to the addiction of needing to reinforce the notion that 'an aluminium frame will break one day', and having to give yourself the additional fix of pretending this time to fail will be 'only a few years'. You obviously own a steel bike, and are conscious of the fact an aluminium one would be lighter, so whenever you're lugging the thing around rather than consider getting an aluminium one instead, you obviously need to imagine yourself coming across me walking along carrying my broken frame, cursing its manufacturers for making it out of aluminium, while you ride off into the sunset chuckling smugly on your invincible steel one.
You just don't see, hear of, or see the results of, enough incidents involving breakages of aluminium frames for this to ring even remotely true I'm afraid Chris

Again you are attributing views to me that I don't have! As it happens I have two steel bikes, one of which is more than twenty years old. But that is more to do with the type of riding I do. If I wanted to race then I wouldn't buy steel - probably CF or, if on a budget, aluminium alloy.

Fatigue life relates to stress cycles rather than time. So the life of a frame will depend on how much use its given. Yours will probably last aeons as, in previous posts, the furthest you have ever ridden is 40 miles. I have a friend who has broken two aluminium alloy MTB frames and bought an top quality frame to replace them (which is still goign). Having said that, he has just bought another downhill bike and I think that has a aluminium frame.

As I have repeatedly said, lots of materials are suitable for bike frames and it is just a case of recognising their strengths and weaknesses and making an informed decision.

 

[bonj2]

I assumed that 'genuine work of crapola' meant that you dind't think it was well suited.



Again you are attributing views to me that I don't have! As it happens I have two steel bikes, one of which is more than twenty years old. But that is more to do with the type of riding I do. If I wanted to race then I wouldn't buy steel - probably CF or, if on a budget, aluminium alloy.

Fatigue life relates to stress cycles rather than time. So the life of a frame will depend on how much use its given. Yours will probably last aeons as, in previous posts, the furthest you have ever ridden is 40 miles. I have a friend who has broken two aluminium alloy MTB frames and bought an top quality frame to replace them (which is still goign). Having said that, he has just bought another downhill bike and I think that has a aluminium frame.

As I have repeatedly said, lots of materials are suitable for bike frames and it is just a case of recognising their strengths and weaknesses and making an informed decision.

whatever. i still dispute that they break within only a few years just due to stress of riding. Your friend must have crashed badly or something, or just had frames made of a crap alloy or with shoddy welding or something.

 

[Abitrary]

With the advent of carbon nanotube technology, we will soon have frames that are 1 micron thick, and weight 1 gram. The carbon nanotubes will also be programmable to imitate the properties of any current frame metal simply by sending an electrical current through them.

Not a moment too soon if you ask me...