New tubulars for old disk wheels (short valve)?
08-11-23, 03:05 AM
#1
Junior Member
Thread Starter
New tubulars for old disk wheels (short valve)?
Hello,
I have an Ambrosio disk wheel that has a small opening for pumping the tire. I searched for new tubulars, but all of them have about 40 mm valve. It is too long, "pipe" adapter won't fit.
Luckily I had a NOS tubular with short valve, rubber still looks soft, so I am ok for now.
But what when I need a new tubular? Are there any modern tubulars with 25-30 mm valve? The wheel is not the one where the opening could be easily cut bigger.
I have an Ambrosio disk wheel that has a small opening for pumping the tire. I searched for new tubulars, but all of them have about 40 mm valve. It is too long, "pipe" adapter won't fit.
Luckily I had a NOS tubular with short valve, rubber still looks soft, so I am ok for now.
But what when I need a new tubular? Are there any modern tubulars with 25-30 mm valve? The wheel is not the one where the opening could be easily cut bigger.
08-11-23, 05:35 AM
#2
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Wow! This could prove to be a real problem over the long run. All the new tires I've bought recently had long stems.
Possibly one solution would be to shorten the stem on the newer tubulars. You would need to find the correct tap for extending the threads for the valve-core. I'd try by removing the core on an old tire or even an inner tube that you don't want any longer.
With correct tap, extend the threads towards the tube. I'd do this with the tap handle facing the floor in order to let gravity assist in removing the metal shavings. You wouldn't want them inside the inner tube. I'd also rig up a vacuum hose to fit snuggly over the valve stem and would frequently give it some good suction.
Once you believe you have added enough threads to the proper length, cut the top of the stem to the required length. Again, I'd do this with the stem facing the floor and I'd use the vacuum frequently. Re-tap to chase the threads where the cut was made.
Reinstall the valve-core and inflate to see how it holds air.
Hope this helps and makes sense.
Possibly one solution would be to shorten the stem on the newer tubulars. You would need to find the correct tap for extending the threads for the valve-core. I'd try by removing the core on an old tire or even an inner tube that you don't want any longer.
With correct tap, extend the threads towards the tube. I'd do this with the tap handle facing the floor in order to let gravity assist in removing the metal shavings. You wouldn't want them inside the inner tube. I'd also rig up a vacuum hose to fit snuggly over the valve stem and would frequently give it some good suction.
Once you believe you have added enough threads to the proper length, cut the top of the stem to the required length. Again, I'd do this with the stem facing the floor and I'd use the vacuum frequently. Re-tap to chase the threads where the cut was made.
Reinstall the valve-core and inflate to see how it holds air.
Hope this helps and makes sense.
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Bob
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08-11-23, 07:44 AM
#3
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08-11-23, 10:27 AM
#4
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I knew this idea was not original to me, but for the life of me I could not remember where I had seen the valve stem shorting accomplished.
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Enjoying the GA coast all year long!
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Enjoying the GA coast all year long!
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08-11-23, 04:29 PM
#5
Junior Member
Thread Starter
Ok, great suggestion, thanks! This looks doable and looks like the thing to do when I need a replacement tubular.
I also thought about installing a sligtly bent valve extension so it would be protruding outside the wheel, but probably needs to be installed before gluing the tubular as there is too little space for srewing the bended extension. Could also cause noise from the wind
And not so pretty.
I also thought about installing a sligtly bent valve extension so it would be protruding outside the wheel, but probably needs to be installed before gluing the tubular as there is too little space for srewing the bended extension. Could also cause noise from the wind
And not so pretty.
