I have a Condor lugged men's 10sp frame from 1976 which is marked "cambio tubing" & "Hand Crafted". I've Googled myself silly trying to find out what kind of tubing cambio is, with no luck. There are no other markings, such as 531 or Columbus.

Do any of you good folks have any ideas?
Thanks

Hello. Same issue. A Condor, made in Mexico based on the frame decal. Suntour groupset, about 1970's, lugged steel frame ect..googled everything. No idea.

Did you get any further searching. I am taking this bike to the l'eroica in Tuscony next week..be useful to have some background info

Knowing the era and post diameter, one can get a good idea of the alloy and whether it is plain gauge or butted tubeset.

T-Mar, not necessarily the alloy but the wall thickness of the seat tube which can be a good start for guesstimating...

The following figures are for 1 1/8" OD seat tubes in brands that were commonly available in the mid 70's:

A seat tube with a 0.6mm wall thickness at the top will take a 27.2mm seatpost;

0.7mm = 27.0mm, 0.8mm = 26.8mm and so on.

Columbus SL and Super Vitus 971, 980, & 983 seat tubes were 0.6mm thick. Columbus SP was 0.7mm.

Butted Reynolds 531 seat tubes were commonly available in 0.5mm, 0.6mm, 0.7mm thicknesses. Straight gage Reynolds 531 had 0.7mm, 0.8mm and 0.9mm wall thicknesses. Ishiwata and Tange produced similar wall thickness tubes.

So, a bike with a 27.2mm seatpost is "probably" made of better quality tubing throughout with light gage butted 3 main tubes...

A 27.0mm seat post could indicate either a frame made of slightly heavier high quality tubing or a bike with butted 3 main tubes.

If the seatpost is under 26.6mm then the tubing is probably lower quality: under 26.0mm it's gas pipe!

If the bike was built in Mexico, there's no telling what kind of tubing they used unless there were an identifiable brand sticker. Not saying there is anything wrong with Mexican made bikes, Benotto and Windsor made good bikes, just that they may have used less expensive tubing, especially in the 1970's. (import tariffs, shipping costs and so on for better quality tubing)

Beyond this info, it's just WAG - wild a** guessing!

verktyg

Chas.

Tubing wall thickness is directly related to the strength of the steel which is a property of the alloy. Provided the frame was not built for a specialized function, one can deduce the alloy based on the state of the art metallurgy for the industry and era. Of course, there will be some overlapping "gray" areas, where there is more than one possibility, but it's far from WAG.

there was something about this "Cambio" tubing on the CR list a couple years ago, but since the switch over to Google Groups I have not been able to search their archives...but I bet somebody there might remember better than I can, if you post a question. IIRC it was a lower-grade tubing but that's about all I recall.