Steel or Aluminium
ctahodgkins
Posts: 13
I'm hoping to buy a new MTB later this year and have been looking at Planet X's On One Big Dog SRAM GX or the On One Scandal SRAM GX (I was tempted by the Hello Dave but cost and weight have pushed it to the back of my mind). What are the advantages of steel over aluminium?
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There are a huge range of steels and almost equally huge range of aluminium alloys. They all have different properties and characteristics. It is important that you research which alloy you are looking for and why. They all have specific names, but let's stick to "steel" and "aluminium".
Steel is stronger than aluminium, so it can have smaller section tubes for the same strength and stiffness as aluminium. Because of that they look spindly (in my eyes). It is springier than aluminium which gives it a more lively feel when riding. Or so I'm told, it is so long since I rode a steel framed bike that I can no longer remember.
It is the ride feel of steel framed bikes that makes them popular. It is this quality that I believe makes steel framed hardtails nicer to ride than aluminium ones. But once you get suspension at both ends, how the hell can you tell? (Not a rhetorical question).
But as I said above, I can't comment on that. There are enough people that think it's worth the money to keep the steel framed bike business actually in business.
The downside is that steel rusts. Steel frames come protected in some way, of course they do! But it would remain a concern for me, having seen my own steel bike rot away when I was an early teenager. Steel is also heavier than aluminium. So for the same strength and stiffness, aluminium bikes are lighter. Aluminium does not rust, it will corrode under certain circumstances, but nothing to worry about.
Steel is easy to join, it can be welded, brazed, glued, rivetted, all manner of methods. It is very predictable and is most unlikely to crack or break. Depending upon how exotic the steel, some heat treatment before and after the weld may be necessary. Aluminium is harder to join, it needs welding with care and will probably need some heat treatment immediately afterwards and maybe before too. It is more likely to crack and then break, but this is such a small problem that it hasn't stopped all the major bike brands using aluminium. If you do get a crack or a break, welding can be done, but it tends to destroy the benefit of any post heat treatment that has been performed, ie the bike will be not as strong. New techniques that I am unaware of may have overcome this of course.
Aluminium frames are cheaper to mass produce, steel ones are cheaper to hand make. To keep the weight down, aluminium tube sections need extensive forming of a type that is difficult to do in steel. That basically puts them outside the ability of DIY frame builders, unless they are content to use standard sections.
Overall, aluminium frames are cheaper than steel. Many reasons, but principally because they are mass produced in their tens of thousands, if not in millions. There are rumours that Giant have a fully integrated frame factory in Taiwan that starts with raw materials and produces frames for not just Giant, but many different brands.
There is a good reason why most bikes today are aluminium frames. They are cheap, reliable and light. But does this make them nicer to ride? I don't know because I have never ridden a modern steel framed bike.2 -
Lets simplify.
Aluminium frames are cheap, light and harsh
Cheap steel frames are heavier and harsh.
Quality steel frames are expensive and superior.3 -
The above is a gross oversimplification. Not all Al frames are "harsh" - ask the owners of several generations of Cannondale CAAD bikes. Al tubes are bigger diameter - but thats because as a material its less stiff (has a lower Youngs Modulus by a factor of 3) than steel. So for the same siffness (resistance to bending) Al has to have larger diameter tubes. But... for use off-road, where you have large low pressure (very low these days with tubeless setups) tyres, often suspension and generally softer surfaces, I don't think it makes a jot of difference. So, go with whatever frame material your best choice bike comes with and enjoy it.3
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Many thanks. Lots to think about but that's the joy of looking at bikes 😁0
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Have you considered wood?0
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To be honest I haven't.elbowloh said:Have you considered wood?
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I once had a bike made of bamboo. It wooden go.steve_sordy said:Get your bamboo bike here!
https://www.nethambamboobikes.co.uk/
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All steels are carbon steels. That is what steel is - an alloy of iron and carbon. By controlling the amount of carbon the properties of the steel can be changed enormously, density not so much. When you start adding in other elements, steel starts to become something really quite exotic; stronger, harder, stainless, and much much more. But the density never comes anywhere even close to that of aluminium.
One of steel's great properties is its response to heat treatment. Steel can be relatively soft or incredibly hard, or incredibly tough, or anywhere in between. The same material can be both at the same time. Think of a Samurai sword that has a very hard edge (so it can be sharpened and stay sharp), but with a tough core that stops the blade from breaking. Whilst aluminium alloys can be heat treated, they cannot match what can be done with steel. Our modern world would be impossible without steel.0
