Frame materials

The best aluminum frames have fat, thin-wall tubes and don't deflect much side to side when you sprint. The best steel frames have smaller-diameter, thin-wall tubes, and flex noticeably in a sprint. Titanium and carbon frames fall in between.

Experienced cyclists often divide into camps, with steel riders carping about the excess stiffness of aluminum and aluminum zealots decrying the spongy feel of light steel frames. He we explain the advantages and disadvantages of the most common frame materials and compare in a graph how stiff they are when compared to steel.

How Stiff is your bike?
A comparison of stiffness (relative to steel) for various frame materials

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steel steel steel steel steel

aint good enough in the context of this discussion

ok - among fine-tour-de-france-steel-frame afficionados ... well .... these guys know from the get-go that they're talking about heat treated boutique alloy steels. Blah blah blah.

Then there is the bike on the street, made from a cheaper high carbon steel - that's 96% iron and 4% carbon.


But the guy asking the question here needs to know that there is a great deal of difference between ordinary cheap 4% carbon 'high tensile' carbon steel and the steel that he is contemplating.....

......which is MILD STEEL .... ie 100% pure iron straight from the blast furnace....

Pure mild steel is not heat-treatable; another name for it is 'soft iron' ... do not confuse this with carbon steel per street frames or alloy steels per racing frames...


4% carbon ... only.... but add 4% carbon to pure iron 'mild steel' and it becomes like a different metal altogether..... with massively changed properties and very much greater tensile strength


(i've tried to write this per the pure facts & eliminating 'opinion' ... now I've run out of steam perhaps someone else can help promote a better understanding of steel....? I feel so inadequate to the task...)

steel steel steel steel steel steel steel steel steel steel steel steel

LOL some of us get out of hand

Ya, trash it and the rest of this topic!

Come on lets beat it to death some more!

I would just use PVC! Its good enough for lawn furniture!

motorhedfred said:

One last thing. With all the concerns expressed about mild steel being softer and easier to bend and therefore unsuitable for frame construction.....where does aluminum (like my Point Beach cruiser) fit into all this ? I'm thinking the hardest aluminum is softer than mild steel. Maybe I'd better not ride it anymore.

Just a thought.

MHF

Click to expand...

it's tensile strength is less but more material is used. chromoly's tensile strength is more, therefore less material is needed.

Strength vs weight vs workability .... alloy steels, aluminium alloys (yeah we spell and say aluminium where I come from)

it's a big big subject, but even a little knowledge of this stuff can surely enhance the fun of messing round the back shed with bikes and engines

I'm rolling round laughing at your reply there, motorhedfred, ha, sorry but it suited my rhetoric to ignore your nomenclature ..... yeah, I know, you got there already.....

I built a hang glider out of PVC and also one out of bamboo, clear plastic sheeting, and fiberglass tape.

The one made of bamboo (It was actually weaker sugar cane) was stiffer and stronger than the PVC prototype. Lighter too.

Experiment, and know that's what you are doing and be careful.