Steel frames - Whats all the fuss about??

MacAndCheese

Hi all,
Seen a lot riders on here wanting/owning steel frames. Just want to know why??
I have nothing against the frames I just want to know your reasons because at the moment it seems a bit odd for following reasons:

1. Like for like they tend to be heavier than the equivalent alu frame.
2. A material that rusts doesn't sound like the best Idea for something that's used outside in Britain.

Is it just that they're fashionable at the moment? or is it because they have a certain ride? (i've read about a certain steel ?twang?)

Convert me.

bungalistic

Steel frames do have a certain 'fashion' status attached to them and that does seem to be down to the feel of a steel frame. Depending on how the frame is made steel frames are usually a little bit flexier than an alu frame, which is a bit more forgiving in the back end, the slight flex absorbs some of the trail buzz so you don't get rattled around as much.

No idea how true that is as I've never rode a alu hardtail frame all that much. I bought my current steel frame as it is cheaper (£180) than the equivalent alu frame (£350+)

MacAndCheese

I thought cost might be an issue for some, which is fair enough. But what about those of you out there with P7s etc?

NatoED

of course alu has a much much much shorter fatigue life (your alu frame will have a 1 year warranty) where as steel will have a life time warranty . steal used in bike frames are mostly chromolium (which means it has chrome in it) and therefore less likely to "rust" .

Alu also rusts just it oxidises as a white powder and this happens in the hidden part of the frame (welds ect) where you really don't want it to be.

there is no real weight difference between steel and Alu . Steel uses less material to make a strong frame where as you need approximately 1.3 X more Alu to make it as strong . Alu is also weakened by welding (hence the need to heat treat Alu frames) where as steel is made stronger by welding . On that note steel is also easier to repair if it does snap.

As a side note my 25 year old peugeot road bikes weighs less than a friends look Alu bike ??
I ride an Alu frame but I'd love to get a nice steel hard tail again .

MacAndCheese

Thanks Nato Ed, good points well made. Only one thing, I thought when alu oxidises the first very thin layer of oxidation acts like a paint and prevents further oxidation deeper into the metal? Unlike rust on steel that will continue to penetrate.

bomberesque

NatoED I have no idea what you are talking about

the fatigue life arguement is bollocks, sorry. I've been riding a cannondale for 20 years and it's not cracked yet. It has a lifetime guarantee on it aswell (although I accept that cannondale have squeezed that over the years) It is however true that if you plastically deform aluminium (bend it beyond its elastic limit) it will work harden almost immediately and crack, which steel will not (at least not as quickly) this is why alu frames started the trend to have replacable deurallier hangers

Also, your figures for relative weight and strength I have no idea where you get these from.

steel at 7800kg/m3 is 3X the density of Alu at 2560kg/m3 and 3X the yield strength (in rough terms) so you can have 3X the volume of material and make it the same weight. This allows the use of much larger tubes, which pushes the material away from the neutral axis, where it is much more effective at resisting bending forces (measured internally as moments about the neutral axis) this feeds back to being able to use less and thus alu frames can be made lighter.

Steel frames are also often heat treated

Steel frames are in general heavier than the equivalent aluminium one.

Right, as to the OP I would say the following reasons in no particular order

cost. Which is interesting as until people like Brant came along, steel had faded from bike manufacture and was the domain of custom frame makers charging boutique prices and 80 quid gaspipe aldi special conversions
fashion/image. Steel is real (etc). No one called a rider on a steel bike an XC racer jey-boi, at least not since the last of the ritchey races frames however many years ago
perhaps a certain nostalgia. Once all bikes were made this way
Steel is harder than Aluminium (which in turn makes aluminium easier to machine, as an aside) but is also 'ARDER if you get my drift
Most importantly, from a difference perspective; steel is more ductile and so the frames feel springier, thus talk about the "ride" of steel frames. This is a very debatable point though as, while a 20 year old alu XC race frame (like my cannondale) is stiff as all hell in every direction (making ride comfort a problem) newer frames are made much more intelligently and many of them ride every bit as comfortably as steel

/edit; as for rusting. you're right about aluminium, it self seals when it oxidises. Anodising is actually a controlled version of this process. I've never seen a quality steel bike rusted through that hadn't been abandoned somewhere for a loooong time

MacAndCheese

Thanks Bomber.

Nostalgia I definitely agree with. (the first proper mountain bike I had was a steel Kona Lava dome - loved it, but was jealous of my friends Rockhopper A1 with its oversized tubing!)

supersonic

It depends on how the frame is constructed.

I wrote a short article in WMB about steel and alu which people may find of use.

Bomberesque is correct on all points! Steel is 3x stiffer than aluminium, but 3x denser. Double a tubes diameter and you increase its stiffness by a factor of eight. This is great for aluminium with its low density - combined with thinner walls, you can get stiff frames for little weight increase. Alu frames do need to be stiffer to reduce fatigue inducing flex, and all alu frames have no flex limits ie lots if small repeated flex will still weaken it eventually. Steel does have a limit ie you can flex it infinite times below a certain amount and it will not fatigue. However I still see alu frames with 5 or more years guarantee though! And the use of caerful butting can add vibration reducing characteristics to the frame.

You can only go so low weight with steel tubing before they get too flexy, or the middle of the tubes so thin they start to buckle. Oversizing just adds too much weight generally with steel. But many like a flexy, comfy ride and this is an area where steel has advantages with its fatigue characteristics.

The lightest steel frames we see are about 4lbs. The lightest alu ones about 2.3 lbs. The latter is still a lot stiffer! The stiffest frame I ever rode was a steel raliegh max ;-)

zero303

Steel frames just look nicer...

Best looking hardtails are things like the Cotic Soul and Genesis Altitudes.

But also, I think the trend for long travel hardtails are causing a resurgence in steel for the comfort factor. If people want longer travel it's to chuck themselves down bigger things and bikes like the Orange Crush are noticeably harsher than something like a Genesis Altitude. Yet both are just as strong an capable as each other.

bomberesque

supersonic wrote:

Bomberesque is correct on all points!

I may have that made into a t-shirt

Anonymous

i bought my steel hardtail for a few reasons, mainly cause i had a load of spares lying around so wanted something to hang them off.

I went for steel as opposed to alu as i hoped would build a more comfy bike with a bit of flex.

I went for the frame i have as i didnt really like hardtils and thought id give them one last go with a really cheap one.

Turns out it was a good idea as i like my 456 so much that im cnsidering the purchase of something a bit more refined.

However, the forgiving ride could be down to the long seatpost and soft tyres.

x-isle

NatoED wrote:

there is no real weight difference between steel and Alu . Steel uses less material to make a strong frame where as you need approximately 1.3 X more Alu to make it as strong . Alu is also weakened by welding (hence the need to heat treat Alu frames) where as steel is made stronger by welding .

Hmm, so how come my Jaguar XJ's bodyshell weight is the same a BMW mini bodyshell??? Not sure I agree with you there....

NatoED wrote:

As a side note my 25 year old peugeot road bikes weighs less than a friends look Alu bike ??
I ride an Alu frame but I'd love to get a nice steel hard tail again .

Hmm again, I recently sold my 18 year old Peugeot 753 Chorus road bike. Top of the range Pug bike back in the day. 753 tubing with Compaq Chorus groupset. This, although very light, was not far off the weight of my Orange 5.....

speedsixdave

bomberesque wrote:

Most importantly, from a difference perspective; steel is more ductile and so the frames feel springier,

Not quite. Ductility is a mechanical property used to describe the extent to which materials can be deformed plastically without fracture - effectively how thin you can make the tube walls, and what shapes you can form with the metal. It has nothing to do with stiffness.

Steel is stiffer than aluminium. Stiffness is measured by the Young's Modulus - this is approximately 200GPa for steel, and 69GPa for aluminium. Steel is therefore almost three times stiffer than aluminium, as supersonic pointed out. But, as noted, it is also three times as dense so the same mass of material will be of approximately equal stiffness if all else were equal.

1970s-80s Alan and Vitus road frames had similar diameter tubes to steel frames of the day, but with thick walls. They were a bit lighter than steel, but much more flexible.

1980s Cannondales and Kleins had much thinner walls than Alans but weighed similar amounts because they used tubes with a large cross-section. This made them stiffer, because the stiffness of a tube is a function of its diameter.

Ductility is important because a ductile steel can be drawn with thinner walls, and therefore produce a lighter tube, at the cost of stiffness.

jairaj

All the above science facts are correct.

But I think that frame design has come a long way these days. Yes the general trait of Alu frames is stiff and general trait of steels is springy. But you can also make a horrendously stiff steel frame and very comfy Alu frame if you design it that way.

Also the parts you use to make the build matter a lot too; seat post, tyres, handlebars etc they all contribute to the feel of the bike. I think people are loosing sight of this and focusing too much on the material things are made from?

supersonic

Very much so - the influence of other parts adds up in the comfort stakes. And as you say, the design of the frame and how is made dictates how it eventually feels - being steel does not autmoatically mean it is 'comfortable'.

Anonymous

supersonic wrote:

Very much so - the influence of other parts adds up in the comfort stakes. And as you say, the design of the frame and how is made dictates how it eventually feels - being steel does not autmoatically mean it is 'comfortable'.

This will be the purpose of the next thread i start, 'do i like my bike cause its steel or cause my saddle is nice'.

lesz42

so want you really want is a frame made of Bamboo/carbon/steel/alloy/nanotube hybrid


how good would that be?

P-Jay

As a layman with very little engineering knowledge I'm a bit sceptical of steel frames being anything other than 'retro fashion'.

10 years ago everything was steel, then technology moved on, and during the 5 years or so I didn't have a bike it just went, goneski, bye bye. Bikes are lighter now than they were back then, at the same time there's a lot more of them. I don't have it anymore sadly, but I'm sure my old GT timber line with canti brakes, 21 gears and not much else weighed more than my Enduro with full suspension, hydro brakes etc.

I'm sure the natural flex of steel takes out some of the buzz, but flex is a two way street it must cause the rear to steer too

As for Alu failing, most of the major players offer lifetime warranties and when was the last time you heard of a frame failing unless your riding stuff it wasn't designed for?

physiosteve

my cove handjob is steel and rides superbly, Im lucky enough to have 2 more bikes which r gucci bikes if u like, and of these:
my ti bikes lighter and seams to float over small ruts at hi speed, the full sus is comfy and handles big drops etc. But ultimately my steel HT cud be the best all rounder, and handle most things with a 140mm fork on.
Its not quite as quick or agile as my ti bike, but the geometry still means she luvs twisty singletrack, can flick around tight trails ad still kills more trail buzz than an alu. She goes uphill better than my full sus and can still handle most things on the way down, certainly any of the trail centre blacks of been too lately, just cudnt nail rock gardens at speed thats all.

For the money these long forked steel hardtails like genesis, cove handjob, cotic soul, seam awesome for wot most ppl encounter 95% of the time. And they work gr8 as SS machines so potentialy ul never out grow em...!

NatoED

in my shop i've had 3 GT frames with cracks in the rear triangle . They all failed around the rear brake mounts around the tube (not near the welds) . An engendering company determined that it was snapped by the forces flexing the frame when the brakes were applied (these were 160mm mechanical and 160mm hydraulic brakes)

blister pus

P-Jay wrote:

I'm a bit sceptical of steel frames being anything other than 'retro fashion'.

Go on a long test ride with a Cotic Soul with decent kit.

P-Jay wrote:

I'm sure the natural flex of steel takes out some of the buzz, but flex is a two way street it must cause the rear to steer too

Comes down to design. Design of both modern steel and alu frames. But all things equal (decent modern design of each) there is a defining characteristic and feel to steel - and to alu. Which you prefer is the million dollar question, and you only arrive at which one you prefer by test riding as many of both as you can. You might not prefer either and click with carbon as a lot do.

CFS

I would say the steel frame thing is largely a fashion, like single speeding.

I'm not convinced by the 'feel of steel' thing.

I ride a 95 cromo steel Trek to work and a 2006 Alu Trek.

The more modern bike is much better off road, probably mostly due to the geometry.

The thinner tubes of a steel frame do look good though and I quite fancy a 456, but this based purely on looks.

blister pus

And when you go test ride a couple of decent modern steel frames, like the 456, or a Soul, you'll be in a better position to determine what's what won't you.

dave_hill

Who says a steel-framed bike needs to be heavy...LINK

NatoED

cfs yeah there is no perfect material for frames (though scandium is close) and it's all up to what you like. i ride an alu frame bike but i'd love to ride steel again it was definitely less harsh to ride hardtail .

But i kid you not with my 25 year old pug . i've just upgraded the wheels and cranks and that took off all the weight. we even weighed it up and it was only 0.1 of a lb heavier than my mates look (not sure which one it was as i'm not so into road bikes).

KonaKurt

All this talk about Aluminium frames failing leave me feeling a bit nervous.

Although I think I'm right in saying that Kona offer a lifetime warranty on ALL their frames, including Aluminium.

KK

Anonymous

KonaKurt wrote:

All this talk about Aluminium frames failing leave me feeling a bit nervous.

Although I think I'm right in saying that Kona offer a lifetime warranty on ALL their frames, including Aluminium.

KK

I don't think they do. Certainly not on all frames anwyay.

supersonic

Most failure is from bad design or welds, or using the bike outside its intended field.

Anonymous

supersonic wrote:

Most failure is from bad design or welds, or using the bike outside its intended field.

Hmm, I hardly ever ride my bike in fields. Is that likely to cause probems?

Northwind

CFS wrote:

I would say the steel frame thing is largely a fashion, like single speeding.

I think if Cotic did an aluminium Soul, I might have bought that but I wanted something that handles exactly like a Soul, and that means getting a Soul or a Soda... But, the give in the rear end is very nice indeed on a long ride, at kirroughtree it saved my, er, ass

Course, some steel frames are stiff and some aluminium frames aren't, my Scandal also had a nice bit of compliance in the rear despite being scandium. People fixate so much on stiffness, as if stiffer = better. Sometimes it is, sometimes it isn't. Some people don't like the feel of a Soul, I don't like the feel of a Chameleon, but they're both great frames.

KonaKurt

I custom built my bike from a (then) new Kona frame (Alu) and was told it had a lifetime warranty by the retailer. I may be wrong, but when I got in touch with Paligap UK, I think they confirmed that, subject to an examination to determine cause of frame failiure....?

I agree with Super, most frame failiures will be due to simple misuse beyond the intended use. All engineering has it's limitations.

KK.