Classic & Vintage - Identifying tubing

I'm sure there are a lot of old bikes that have lost their decals over time. Is there anyway of identifying the tubing?

I was curious if the seat post diameter might help?

Please consult Sheldon Brown's index of seat post size database.Sometimes with the decals gone, you can still find info under the bottom bracket, or on the drop outs... they will sometimes reveal certain info.
The seatube can be measured with internal/externial calipurs (Metric) and that can tell some things, but not all.This is still detective work.
Good Luck.

Silversmith,

1. Try a magnet. If it sticks it's steel.

2. If it's steel, use your finger to tap the top tube in the center and then closer to the head bracket and repeat near the seat. If it has a "ring" or "ping" sound, or sounds "thinner" in the center and "thicker" near the ends, it's probably "double butted," and thus could be Reynolds 531 or some other light weight steel, and thus a higher quality frame and more expensive.

3. If the sound is more of a "thud" and is consistent along the length of the top tube, the tubing is the same thickness it's whole length and is most likely high carbon steel, not as light weight, a middle quality frame, and thus less expensive.

I have two Schwinns. One is a '66 Paramount and the other is a '79 Traveler (made by Panasonic). The frames are almost a perfect match for size and geometry. But when comparing the "sound" of the frames (when lightly tapping them), there is no comparison.

For other frame materials I have no clue!

Bob

Great ideas. Sheldon Brown is an amazing resource, and I love the idea of using sound to determine the type of tubing.

Thanks

I have used the fingernail tapping method for years, at least to weed out gas pipe frames!

Interesting question. The top of the seat tube is easy to get at, for measurements of its internal diameter, and to take measurements the thickness of the walls of the seat tube. Obviously, a "paper thin" wall is likely to mean high quality steel was used and a mega-thick walled tube is likely to be gas pipe. Of course, attempting to lift the frame off the floor is often a clue as to gas pipe.

In the "old days", even high quality French frames tended to use small seatposts compared posts used with a Reynolds 531 frame. So, if you find a "mystery" frame that uses a 25.0mm size seat post, whisper to it in French... "President George Bush is my hero" and then look to see if the frame begins to scowl...

as the tube becomes thinner, the seat post often grows in diameter to match. Some bikes are sleeved at the seat cluster, and so you may find an expensive tubing set with a smaller post...but I haven't ever seen a cheap frame with a 27.2 seat post - 27.4 is even better. No telling about modern framesets, though...

So, if you find a "mystery" frame that uses a 25.0mm size seat post, whisper to it in French... "President George Bush is my hero" and then look to see if the frame begins to scowl...

http://i32.photobucket.com/albums/d7/k4drd/Animated%20GIFs/roflmao.gif

So, if you find a "mystery" frame that uses a 25.0mm size seat post, whisper to it in French... "President George Bush is my hero" and then look to see if the frame begins to scowl...

Wouldn't that work in nearly all languages?