When I bought my fastback in 87, it came with all 5 oem us royal tires-spare never down.
Here's what one looks like in great condition for its age.
If the tube had been natural rubber, you would have cause to be jubilant over it. However, tubes have been made of a butyl elastomer since during WW II, and that''s what you have there.
The butyl compound came out around the middle of the war, as a substitute for the tubes that we had used. Previously, natural rubber had been used in all tubes, and they would lose pressure such that you needed to check your tires every two weeks or so. With new butyl tubes in their tires, owners found that they didn't need to check air pressure at all for months. Following the war, the industry never did go back to natural rubber inner tubes. Tubes in use today are the same as the replacement tubes that an outfit named Polson made during the war.
My father was in the tire business, and he sold possibly thousands of Polson tubes. They were truly a Godsend.
I have a '69 Harley that I haven't ridden for 30+ years. One tire is original with a new tube last driven, and the other tire is a replacement, matching the originals. The bike has been parked in my garage all this time, and when it was moved and run for the first time in around 5 years, the tires needed very little air.
NOW, one other little sideline. Natural rubber tubes are still used in airplane, earth mover, and drag racing tires. reason for that is that butyl tubes can' stand up to the heat generated in those tires, but natural rubber can. They still need pressure checks frequently.
Sorry to have rained on your parade, Jeff!
Doug. Your post confuses me in that I'm saying, there oem 49 tubes regardless of what compound there made from not knowing myself, seeing how 8.20.15 tires were first introduced in 48, but a great story from you as usual=Thanks.
I figured few in the club have ever seen one, so I posted it for the archives :<)
What I as saying was that the material in inner tubes that was used as a wartime substitute became the standard used forever more. The car owner like yourself, nor anyone else was totally aware that inner tubes were no longer like those before the war. The Butyl substitute was one of very few that ended up as in improvement.
I sort of think that there were some natural rubber tubes to be had after the war, for passenger car use. Goodyear had a dual-chamber safety inner tube (Goodyear Lifesaver?) in the early fifties, but It was a short-lived product. I also seem to recall Firestone having some kind of a dual-chamber tube that never went very far. But, they both could have been Butyl....I dunno.
never lasted very long. I seem to remember that Firestone had some kind of dual chamber tube as well, but memory is foggy on it.
There were individuals who were adamant about wanting prewar style tubes in their tires, but they were somehow persuaded to accept current technology.
Well, what I want to know is why the tube says both 7.50 x 15 and 8.20 x 15? Seems to me that nearly 3/4 of an inch is pretty significant?
Maybe it's minimum to maximum inflation? It'll work in any tire from 7.5 to 8.20?
I've had motorcycle tire tubes that for example say 3.25-3.50 etc.
Have any pictures of your 69 HD Doug ? I started riding bikes in 1970 on a HD 250 Sprint made in Italy...my first and last HD :<)
There's a decent pix somewhere here, but I'll need to look for it. Just now, it's in the garage, but decent pictures are never good in garages.