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natprice

I have a Gitane Professional Tour de France which my mother purchased in the mid 1970's. The bike is very light and it was the top of the line at the time and supposedly has an aluminum frame. The paint is all original and it still has the original decals. After almost 35 years though the bike's frame now appears to be rusting. The bike has been stored inside but it was in an oceanfront house in Florida. Everything rusts in Florida, just usually not aluminum.....Were these bikes also available in steel frames? Has anybody had similar problems? I wish I had a magnet handy so I could find out if the frame is in fact steel but the rust seems to almost conclusively imply that it is...

sandranian · Site Admin

It is a steel frame, made of Reynolds 531 tubing. Aluminum frames were not introduced to the mass market until the 1980s.

It is light because the tubing material was made that way: It was "butted", meaning it was thicker at the ends where it was joined together (at the "lugs"), and thinner in the middle, where it didn't need to be so strong. The tubing was more expensive to manufacture than "straight guage" tubing, and much more than rolled "seamed" tubing, found on very cheap bikes. This is why collectors and bicycle enthusiasts look at the use of Reynolds tubing as an indication of a quality frame. Most builders wouldn't spend so much on the tubing if they weren't going to build a higher-end frame, which the Tour de France certainly was. You should clean and polish the frame to preserve it. I would suggest asking your local bike shop how to prevent rust on a steel frame....

natprice

Thanks for your quick reply. It seems unlikely that the frame would still even be in one piece if it is solid steel and from what I have read the paint job on these bikes wouldn't exactly offer much protection. Were no Tour de France bikes made with aluminum frames before the 1980's?

lofter

no, vitus startede to produce aluminum bonded frames in the 80s. gitane did come out with a vitus (gitane badged)frame in 87. then came onboard the the aluminum craze later.

natprice

I agree the frame must be "steel". From what I have read online it is actually a steel alloy made with manganese and molybdenum. This would explain why the frame hasn't completely rusted away and would also help contribute to strength and lightness.

sandranian · Site Admin

While the paint jobs on Gitane aren't as pretty as the stuff available on some Italian bikes, they are certainly good enough to prevent the bikes from rusting away! The materials that make up the 531 alloy make up less than 2% of the total material, hardly enough to prevent it from rusting away. There are thousands of steel bikes from the 1970's and before which are in fine riding condition, many of which survived in the East and Southeast. As long as they are kept inside, they are usually fine. Even a bicycle stored outside in Arizona will rust after 30+ years....

natprice

you are correct. for those interested the most detailed chemical composition specification i could find for Reynolds 531 is:
Carbon: .23-0.29%
Sulfur: 0.045% max
Silicon: 0.15-0.35%
Phosphorous: 0.045% max
Manganese: 1.25-1.45%
Molybdenum: 0.15-0.25%
the manganese and molybdenum were most likely added to increase strength and machinability leading to the thinner walls and lighter frame.
"Even a bicycle stored outside in Arizona will rust after 30+ years" .....so one would expect a bike stored oceanfront in florida (granted not outside) for 30+ years to be severely rusted....??

sandranian · Site Admin

....not if it was stored indoors. It would be fine. But yes, I would expect that if it was outside for 30 years in Florida, it wouldn't be in the best of shape!

natprice

you would be surprised....salt literally collects on our windows, even our refrigerator rusts and that is in the air conditioned part of the house. i am just amazed at how well the steel frame has lasted, it just seems inexplicable to me. i remember my brand new bike starting to rust in about a year...