My old friend Bruce just wrote to me about his two ( 2 ) 1970's Raleigh Grand Prix bicycles . I believe that both are what Raleigh called 25 1/2 inch frames ( center to top ) . One is entirely original , from 1974 . The other is perhaps a 1971 , and was sent to him as a bare frame-set , which he built up from whatever component parts were handy , and seemed to work well .
Hey, I am very curious about your theory on this very unscientific observation.
That early 70's Grand Prix frame that you sent to me (by the way, I love the way it rides!) - The frame is the tiniest bit too big, which means maybe it is the right size. I have it equipped (constructured?) with some good Nippon 700c wheels, Sugino Maxi crank, center pull brakes (one Weinmann and one Universal) with some nice gum-hooded Weinmann levers, Sun Tour der., TTT stem, no name bars and it rides fantastic, I mean better than it should!
Anyway, the question: When I ping the top tube with my thumb (like shooting a marble) there is steel rinnggg. When I do the same on my later Grand Prix, there is a very flat, almost no response sound.
Just an oddity or different tubing?
Bruce Cumberland [ to comply with C. R. List rules , I'll add that he lives in Indiana U.S.A. :^) ]
Raoul replies :
Hey Bruce ,
What a mongrel ! What fun ! What a cool bicycle !
About the ringing of the top tubes , there are several factors .
Those Raleigh frames could have been made with distinctly different tubing . But I doubt it . I'd guess ( a strong guess ) that whatever "20-30 High Carbon Steel Tubing" ( "mild steel tubing" ) they might have been using , the different batches were probably all very similar .
( Were both of your Raleigh Grand Prix bicycles made in England ? Or was one made in England by Raleigh , and the other made in Holland by Gazelle ? )
And , even if there were some batches of distinctly different tubing , with meaningful differences , could you actually hear the difference ? There has been debate , for years and years , about "pinging" the three main tubes , to learn something about the tubing . If someone COULD actually hear something useful from doing that , I've always thought pinging a bare frame would tell you more than a built-up bicycle . Some folks think they can hear the difference between plain-straight-gauge tubing , and double-butted tubing . Some folks think the idea is silly .
HOWEVER! You are obviously hearing a BIG difference between your two frames ! So , what's my guess ? Well , we both love neat old Raleigh bicycles . But we both know what the quality control was like , for Raleigh during the 1970's . . . Some of those bicycles were much-Much-MUCH better than others !!!!!!
My guess is that there are "voids" ( gaps , bubbles ) in the brazing around the lug at one end , or both ends , of the top tube , on the bicycle that sounds flat - with almost no response ( a "dead" sound ) . Some of the brazing on those Raleighs was ( is ) just so VERY much better than other brazing !
Remember that damaged 1973 Raleigh Super Course ? It was sent to me recently with NO packing . It simply had both wheels removed , and then was tossed in a box . Then it was shipped to the wrong address in the wrong state . Then finally it was shipped to me . Remember ? During shipping , along with the rear stays being badly bent , the seat-lug took a real pounding . When I tried to fit the steel seat-post back in , it was impossible . So , I very slowly , very gently , very carefully , bent the seat-lug , back to its correct shape .
That old seat-lug had a visible gap , all the way around the top . I mean I could see where the original paint had gone down between the top of the lug , and the top of the seat-tube ! There was a tiny air space , all the way around ! And the "ears" of the seat-lug , where the binder-bolt slips in , where not too pretty either ! But , my point is this - as I was very gently bending the seat-lug open once again , I heard two very clear "pops" , as some more of the brazing let go .
That frame will almost certainly never be ridden again . And if the joint between the seat-lug and the seat-tube ever did separate , it would be a fairly "fail-soft" kind of failure . But what I'm saying is , that particular joint looked really ugly . It looked really weak . And , apparently it not only looked weak , it was weak enough to make scary noises just from being returned to original shape and size .
Do you think I need to go "ping" all of my old bicycle frames now ? How long do you think it might take to tear ALL of the bicycles down to just bare frames ?? Should I use only a genuine VAR brass hammer ???? What do I do if I find some frames with tubes that go "thunk" ??????
Raoul Delmare
Marysville Kansas U.S.A.
where sometimes things
go "thunk" in the night