MMACH 5

Is there a chart out there that represents a general comparison between frame materials?

Primarily, I want to know about weight when it gets into the different alloys. I know that CF is lighter than aluminum which is lighter than steel, etc.

But what about manganese alloy versus Chrome-Moly versus Carbolite? Is one of these lighter than the rest?

MichaelW

Apart from being a bit of troll subject, material comparisons are pretty meaningless.
For a given volume, Ti is approx 1/3 the weight AND 1/3 the strength of equivelent grade steel*. Al is 1/2 weight and 1/2 the strength of steel. That is why Al frames do not weight half as much as steel frames; You need more material to achieve the requitred strength and only save a very small amount of weight. Even then, a cheap Al frame is heavier than an expensive, handbuilt steel frame.
* Many comparisons between materials use the lowest grade of steel as the a comparison against expensive Ti, not the highest grade of heat-treated steel.

seely

As the above poster said, more or less, much more of the weight factor of a bicycle depends on the manipulation of the tubing, skill of the builder, etc. There are sub 3lbs steel road frames out there, and there are 5lbs aluminum road frames out there. Talking the raw weight of a given material seems somewhat pointless I'm afraid. CF isn't actually any lighter than aluminum in most bicycle applications. Look at the weight of a good aluminum seatpost vs. a carbon seatpost. The aluminum is usually lighter. Look at the weight of a carbon Cannondale Synapse vs. a aluminum Synapse with the same components--virtually no weight difference. Cannondale Six13 vs. a R5000--no weight difference. The same is true of other manufacturer's lines as well. When it comes down to it, carbon is usually added for comfort and not necessarily weight savings.

MMACH 5

How can I attain my goal of being a total weight weanie if there's no real weight savings by dropping the steel frame?

Nessism

The basic rule of thumb is that materials in the same metal family all have the same stiffness (modulus of elasticity); regardless of the alloy type of steel/aluminum, they all have the same metal stiffness (assuming the cross section area is the same).

Another rule of thumb (with in the scope of the bicycle arena anyway) is that materials in the same family have the same density (weight/unit area).

Compared to steel, aluminum is 1/3 as strong/stiff/dense.

Compared to steel, Ti is 1/2 as stiff/dense and roughly the same strength as medium grade steel.

Carbon can not be compared because the fabric lay-out determines the characteristics.

For some good info read the following link.

https://www2.sjsu.edu/orgs/asmtms/artcle/articl.htm

MichaelW

Weight weanies worry over grammes. The weight saving from using Al in an ultralight frame compared to a steel ultralight frame are real but not as much as you would guess from their relative densities.
I plead guilty to having an Al bolt on my bike but it is to secure a lamp and in mitigation, I was given the bolt by a friend.

Retro Grouch 

So how much money do you have?

RockyMtnMerlin

Thanks for the link. I certainly learned some things I didn't know. And I like the botom line. Any material used in a poor disign will not work well!

grolby

When you get right down to it, good engineering will allow any bicycle frame to transcend its material properites. Steel can be light, titanium can be stiff, aluminum can give a nice ride. Engineering is far more critical to the weight, ride and handling of a bicycle than its material properties. I happen to like steel bicycles, but I will be the first to admit that it's an irrational, more emotional than intellectual belief in its superior qualities and general indestructibility. I believe it, but believing it means coming to terms with the fact that it's not true .

CdCf

Couldn't agree more!

HillRider

You have it backwards and still not correct. Al is about 1/3 the weight and 1/3 the stiffness (not strength) of steel. Ti is about half the weight and 1/2 the stiffness of steel. Ti alloys can be as strong or stronger than common Cr-Mo steel alloys.

For future reference, the densities of these metals are approximately:

Al = 2.7 gms/cc
Ti = 4.5 gms/cc
Steel = 7.9 gms/cc

MMACH 5

Likely one of the most informative pieces I've run across. Thanks for posting it and thanks to everyone for responding.

I think this nicely sums up my lesson for the day:
Thanks again.

DannoXYZ 

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Properties of most materials used in the bike-industry can be researched here: MatWeb - material property data. However, comparing simple materials properties is only relevant if you're comparing two bikes of exactly the same dimensions and design. Good engineering would design to take advantage of the unique properties of each material. You can get good frames made from steel, aluminium, titanium, carbon, magnesium in the 2.0-2.25 lb range. If you pee and take a big dump before a ride, you can lose -5 lbs...