armstrong bike project

[SkipdiverJohn]

I have a mid/ late fifties frameset that may be made of A & P Kromo: the painted frame is 1875g/ 4.13 pounds, painted fork is 695g/ 1.53 pounds. That's for dimensions of a 22 inch top tube (centre to centre) and 22inch seat tube (centre to top).

It's lighter than my early 80s 531 frameset. Some have said Kromo frames are consistently lighter than other steels of the time.

Kromo may well be the underlying recipe that resulted in Reynolds 501, which can be a very decent tubeset. As regards unit weight steel is steel. No matter how low or high grade it is it's weight is virtually identical as around 97-98% is iron anyway and the only variation is due to slight differences in the atomic weight of the alloying elements deployed. A Kromo frame will only weigh less than an equivalent Reynolds frame if the tubes were drawn to a thinner gauge. The chemistry differences between mang-moly and cro-moly alloys are too small for this to have any meaningful effect on the unit weight of the steel.

 

[avecReynolds531]

Kromo may well be the underlying recipe that resulted in Reynolds 501, which can be a very decent tubeset. As regards unit weight steel is steel. No matter how low or high grade it is it's weight is virtually identical as around 97-98% is iron anyway and the only variation is due to slight differences in the atomic weight of the alloying elements deployed. A Kromo frame will only weigh less than an equivalent Reynolds frame if the tubes were drawn to a thinner gauge. The chemistry differences between mang-moly and cro-moly alloys are too small for this to have any meaningful effect on the unit weight of the steel.

Yes, agreed that it's the gauges that will make the differences in frame weight: apologies, should've made that clear in the last post.

I haven't yet been able to find out what A & P Kromo (and SAQ) was drawn to, or could be drawn to - it's interesting that some Kromo owners are recording lower weights than equivalent steel frames of the time.

Here's an Accles & Pollock advert from 1931:

The OP's Armstrong could be an A & P frame - maybe there are stamps on the frame or fork?

Whatever, it's fascinating history of the heritage of Britain's engineering brilliance.

 

[Eric Olthwaite]

Back in the days when people thought 5 gear ratios is all anybody really needed. Lunatics.

 

[Dust]

Looks like a good project

 

[supersixone]

new project 1950s armstrong possible consort model
It's got the gran sport rear mech orginal crank Williams pedals poss handlebars
Mocked it up to see how it looks
Paint work is scractched but the blue paint is still bright going to clean and wax frame
And use as many parts as I can
The frame is solid and no dents