Framebuilders - Cro-Moly Steel vs. Aluminum

If you had two frames of similar size, say 60 cm, how much lighter would the aluminum frame be versus a steel frame. I am just looking for a rough estimate.

- IANAFB (i'm not a frame builder), but wouldn't this depend on the steel or AL type and tubing used?

Tubing diameter, butting, geometry, etc.... Density of alloys is pretty fixed, unless you're building in 8000 series.

OK. I didn't think it was that complicated. I'll try a different approach.

Okay, I will make it easier for you:

Two frames. Identical geometries nd tube sizes. The Al bike will be one third the weight. But it will collapse.

Usual? Two 17 inch frames in 853 and say, Easton GX2? The Gx2 will be about 1.4kg, the 853 about 2kg

OK, thanks. That is ablout what I was looking for. I was guessing that frames were heavier than that. I was thinking a steel frame could be a bigger penalty than the aluminum one would be.

My WAG (wild ass guess) is that a medium quality Al frame will weigh about 1 lbs. less than a similar quality steel frame.

Ed

Okay, I will make it easier for you:

Two frames. Identical geometries nd tube sizes. The Al bike will be one third the weight. But it will collapse.

Usual? Two 17 inch frames in 853 and say, Easton GX2? The Gx2 will be about 1.4kg, the 853 about 2kg

Falanx, I'd be suprised if a 17" high end steel frame was much more than 1.7kgs. Heck, my 62cm 'compact' road frame which is a mix of OX platinum and Foco is 1840g.

It's impossible and pointless to make any comparison, deanp, but if you assume a 250g difference you'll be ballpark for the sake of the argument.

I appreciate all of yours' input. You confirmed for me that it is much less of a difference than I thought it would be. You have given me some great food for thought.

Falanx, I'd be suprised if a 17" high end steel frame was much more than 1.7kgs. Heck, my 62cm 'compact' road frame which is a mix of OX platinum and Foco is 1840g.

It's impossible and pointless to make any comparison, deanp, but if you assume a 250g difference you'll be ballpark for the sake of the argument.

I think you would be closer to the truth if you doubled your 250g estimate.

High end 62cm compact road frame = 1840g (4.1 lbs)
58cm Cannondale CAAD7 (from weightweenies.com) = 1298g (2.9 lbs)

I love steel by the way. It's all I ride. :)

Wow, maybe Aluminium is actually lighter than I think.

Guess that shows how much I actually care. :D

Okay, lets' just say somewhere between 250 and 500g and call it even!

So lets see now.....the difference for me is somewhere between .2 and .5 of a percent in total weight, and the corresponding extra wattage it takes to drag that up a hill.

Wild guess.....400 watts big effort......divided by 100 multiplied by .2 equals .8 of a watt.

Wow.

I'm sure I waste more than that every pedal stroke with my horribly inefficient human style pedaling action and power delivery.

Wow.

That's probably the equivalent of adding bladed spokes to the front wheel or tilting my upper body an extra 2 degrees to lower my frontal area.

See, there is method to my ambivalence!

Falanx, I'd be suprised if a 17" high end steel frame was much more than 1.7kgs. Heck, my 62cm 'compact' road frame which is a mix of OX platinum and Foco is 1840g.

It's impossible and pointless to make any comparison, deanp, but if you assume a 250g difference you'll be ballpark for the sake of the argument.


What can I say, I like my steel immortal. And the best way to do that is some big-assed gussets. I took the weight, BTW from Kona's Explosif, which isn't 853, you're right, but it's pretty good as a ballpark. I was working to MTB weghts...