Why 'STEEL IS REAL' - the science bit!

[mikee]

i'm not an artist but........

 

[FluffyChicken]

shaun, just so you know.
Prestige also made (may still do) 6/3/6 tubing* for top and down, while not of course tagged with the MTB naming
You might like to see KOna Steel info
http://www.retrobike.co.uk/gallery2/v/M ... 8.pdf.html



Interesting to note the '97 Hot 853 was specced thinner and they use thicker for the 'mass' production Explosif in later years
'99 Tech info (Kona)
http://www.retrobike.co.uk/gallery2/v/M ... s.pdf.html


and if you want to get lost in some detail try here
http://equusbicycle.com/bike/tange/tang ... index.html
and look at some other things at that site.


*that is still thicker than a beer/cola can

 

[shaun]

i'm not an artist but........

- DEFINITION OF ARTIST: a person engaged in one or more of any of a broad spectrum of activities related to creativity.

...dunno 'mikee', after having spent a while drooling over your stunning collection of 25 stylish beautiful retro classics that you have personally created, you seem to fall into the definition of an 'artist' and not know it.

 

[shaun]

Thanks 'FluffyChicken' for that contribution that I read with great interest. Always nice to actually learn something new, even at my age!

 

[Rich Aitch]

I think you can overestimate the toughness of some materials but people tend to underestimate just how tough steel is- or how light it can be. I never realised until I started reading "The Most Dangerous Enemy" but the Hurricane fighter plane was made from hi-tensile steel tubes rather than an aluminium tubed space frame like I thought.
It's flexibility is also impressive, I can remember one Retrobike ride where a heavier rider [Who shall remain nameless] showed how much springiness there was in his Orange Clockwork frame by leaning it away from him and pressing most of his weight through the bb shell, it must have deflected more than half an inch.

 

[velomaniac]

showed how much springiness there was in his Orange Clockwork frame by leaning it away from him and pressing most of his weight through the bb shell, it must have deflected more than half an inch.

This is not always a good thing. I had a early Dawes Galaxy tourer that did the above. When heavily loaded and descending steep hills a tank slapper effect could occur where by the entire frame flexed laterally and messed up the handling to worrying degrees. Later 80's Galaxies cured this by greater diameter tubing in the top and down tubes but of course this added weight. Although Aluminium cant be repaired by a backwoods welder I can see why several tourer makers opt for aluminium frames such as Cannondale and Koga Myata.

 

[apache]

Slightly off topic, but how about a stainless steel aeroplane? Bristol 188. Stainless for its heat resistant properties at high speeds.

They've go a real one at Cosford. Well worth a look. (for this, the Lightning prototypes, the TSR2, the Vulcan etc - and its free!)

 

[VTFoco2001]

Steel is strong, but its specific strength is less than either aluminium or titanium. The reason you can build a steel mtb frame with thinner walls than either aluminium or titanium is simply that its density is greater.

The tube you quoted, 31.8 x 9-6-9, would be a reasonably substantial top tube, but you won't often see a standard 4130 top tube of less than 28.6 x 9-6-9. Heat treating makes the material stronger, so an mtb can be made with heat-treated steel with much thinner tubes. The Columbus Cyber top tube on my Kilauea is a 28.6 x 7-4-7, which is about as thin as it gets for mtb.

Aluminium tubes aren't all that much thicker. Easton Ultralite has a 0.8mm top tube, and Easton 7000 Scandium went down to 0.65. In titanium, you tend to see 0.9mm plain gauge as the thinnest. It has the opposite limiting factor to aluminium - it could go to similar thicknesses without breaking, but butted titanium isn't often used for mtb because it would be too flexy. The limiting factor for aluminium is breakage - it is still quite stiff at 0.8mm.

I don't think there's any justification for thinking in terms of 'scary light'. Frame builders operate within the terms of the warranty given by the tube manufacturer. The manufacturer will specify the thinnest selection of tubes that are suitable for mtb and no frame builder will go below that for a production frame.

Aside from the warranty costs, there's nothing to stop a builder using road tubes for an mtb frame, but the only case that I've heard of was mid 90s Ritchey team frames, some of which are lighter than an mtb tubeset. Even there though, Tom Ritchey knows a lot about tubes and would have taken into account (a) that Tange were quite conservative with their specification (8-5-8 being their lightest for mtb) and (b) that a brazed join weakens the tube less than a TIG weld does. He used to say those frames were built to last no more than one racing season, and some of them didn't even make it that far. Whether they were actually faster than a slightly heavier but stiffer frame is another issue. Only for a very light rider I would guess.

My MTB frame (Van Tuyl) is handbuilt using Columbus Foco tubing. Foco tubing used commonly in hand built road race frames. I ride it now for 11 years and the frame is still going strong. No noticeable increase in flex due to ageing. If it fails (let's hope not...) I want exactly the same frame material and geometry back.

 

[shaun]

My MTB frame (Van Tuyl) is handbuilt using Columbus Foco tubing. Foco tubing used commonly in hand built road race frames. I ride it now for 11 years and the frame is still going strong. No noticeable increase in flex due to ageing. If it fails (let's hope not...) I want exactly the same frame material and geometry back.

I know exactly what you mean. I have owned and ridden all frame materials in my time, but I am now 'addicted' to the feel of my latest retro Reynolds 853 tubed frame and, like yourself, I would simply have to replace it if anything bad ever happened to it, even if it meant having one custom built.

 

[rudymexico]

Why the big manufacturers are not producing any high end steel frames?

I am a believer, steel is real