78 Special Wheels

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Just want to throw this out there.
Does anyone know why Yamaha insisted on using tubes in the first year 1978 Specials with alunimum wheels?
The next year, the 1979 Specials came equipped with tubeless tires.
My 1978 Special has had tubeless Spitfire II tires on it for at least the nine year I have owned it with no leaks or balance issues.
Are the wheels any different from 78 to 79 on?
 
Hey RG thanks for chiming in,I hoped you would!
I just ran out to the garage and checked mine and my wheels have no mention of being suitable for tubeless tires.
I know the Clymer and the Yamaha both state the 78SE with alunimum wheels must have tubes.
I wonder if they changed thier tune mid production in 78 and found the wheels were OK using no tubes?
I have never had a tire go down or had any balance issues,but this was a topic I was always curious about.
My bikes vin# is 447304683.
Production date 6/78.
 
The Special mags come in tubeless, (states on the mag), and rims that are for tubes. I have heard of people using tubeless tires on non-tubless rims without any problems but i would not do that myself for my own piece of mind
 
There's no difference, really. Tubeless tires were a rare (new) thing then. I have both here, and you can't tell the difference. Really. :) You will need to drill the valve stem hole a little larger.

John
 
There's no difference, really. Tubeless tires were a rare (new) thing then. I have both here, and you can't tell the difference. Really. :) You will need to drill the valve stem hole a little larger.

John


My father bought a set of Lester mags for his '76 R90 so he could run tubeless tires, it was really a new thing back then. Some people considered it risky to run without a tube.
 
Skip, made "for" the USA not made "in" the USA.
I think in the first year or two they had porosity issues. I don't have a not suitable wheel to look at. And I didn't think to check when I changed tires on the 81. I read somewhere that tubless tire wheels have a lip on the bead seat area. This lip is on the inner edge of the bead seat. It was there to help keep the tire on if the pressure got low.
Oops. I just realized I do have a not for tubless tire wheel. It's the disc brake wheel on the 75.
I quess I could break the tire down and look at the disc brake wheel and break down the 81 wheel and look. LOL, like thats gonna happen. I don't mind changing tires when they need it but I ain't gonna do it just to look at the bead seats.
If i think to i'll check and take pics on the wheels as I change tires.
 
It seems that there is confusion with the tube and tubeless rims on the specials. The rims are the same casting, regardless of year, but the later models, 80 on, had " for tubeless tires" stamped on them. So what is the difference? The later wheels had the valve flange machined flat, to compensate for round wheel, that is all. No other changes or modifications, no safety lip on the bead, and the porosity thing, who knows. Many people have run the tubeless tires, with no ill effect, me included. Just use a new style valve stem, and check your tire pressure before a ride, but you do that anyway, right. I hope this helps with any confusion. John.
 

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It seems that there is confusion with the tube and tubeless rims on the specials. The rims are the same casting, regardless of year, but the later models, 80 on, had " for tubeless tires" stamped on them. So what is the difference? The later wheels had the valve flange machined flat, to compensate for round wheel, that is all. No other changes or modifications, no safety lip on the bead, and the porosity thing, who knows. Many people have run the tubeless tires, with no ill effect, me included. Just use a new style valve stem, and check your tire pressure before a ride, but you do that anyway, right. I hope this helps with any confusion. John.

Thank you, that's what I've been saying. I think the porosity thing was just a wild guess, when the real reason was there weren't any tubeless tires yet. The first tubeless bike tires came about in 1978 in Europe, can't find the first in US, but it would be similar. Why write on wheels about tires that didn't exist when they were cast? :)

John
 
Thank you Johns,
I think we can put this this thread to rest. You guys nailed it.
The picture show the factory modification to the wheel to accept a tubeless valve stem assembly.Great picture! Thank you.
 
It seems that there is confusion with the tube and tubeless rims on the specials. The rims are the same casting, regardless of year, but the later models, 80 on, had " for tubeless tires" stamped on them. So what is the difference? The later wheels had the valve flange machined flat, to compensate for round wheel, that is all. No other changes or modifications, no safety lip on the bead, and the porosity thing, who knows. Many people have run the tubeless tires, with no ill effect, me included. Just use a new style valve stem, and check your tire pressure before a ride, but you do that anyway, right. I hope this helps with any confusion. John.
When you say new style valve stem is that the same thing as the only valve stem I see available or is the a different valve stem for each of the mags pictured ?
 
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