Changed tire, replaced inner tube - 300 miles later valve stem shears off

Hey guys, need some advice on what I did wrong.

After 14+ years of perfection, my 1921 9B touring finally got a flat tire. After receiving valuable advice from this forum, I removed the lock ring, replaced the inner tube and re-installed the lock ring.

Yes, the lock ring installation was as bad as everyone warned. And cursing did help.

I thought everything was great until after about 300 miles of use. My tire went flat again. After removing the lock ring (very easy this time) I saw that my valve stem had been completely sheared off.

What would cause this? Lack of proper tire pressure? Not lining up the inner tube properly when inflating the tire? Bad inner tube?

I'm thinking I did not properly inflate the inner tube properly.

I'm looking for any advice.

Thanks.

I replaced all the tires and tubes on my '32 sedan and proceeded to drive to the Trek. After 300 miles I got a flat just outside of Norwich, NY. The valve stem came off the stem. I felt that the tube was defective. Universal tire replaced it free of charge and even overnighted it to Cazenovia.

I think that if the tube was installed wrong, or crooked, it would have failed much sooner.

It has been my experience that under-inflation causes the stem to shear off after braking.

It has been my experience that under-inflation causes the stem to shear off after braking.

That sounds reasonable, however I ran 25 pounds in a heavy Packard Phaeton for years to keep tire wear uniform and never had a problem with the valve stems. It's all probability --- what are the chances? I agree that the more underinflated, the higher the chance that you can get a stem sheared off.

If the valve stem is shearing, then the tire itself must be moving on the rim. How do you mount the tire? You need a lubricant to get the rubber onto the rim, but dish detergent is not so good because it always remains slippery. What I use is a tire mounting paste (I'll see if I can dig it out for the name) which is available at auto parts stores. This is sort of the consistency of cool butter and is very slippery for mounting ease, but when it dries it hardens into a "glue-like" substance which helps to hold the tire in place.

But from my experience new inner tubes are of very poor quality compared to a generation ago. All or many vintage car tires and tubes are made overseas in countries we once fought in wars. For instance, Vietnam, of all places. And the quality of their products is just terrible. Like anything made in China. If you have old American-made tubes which hold air, don't replace them !! You'll regret it.

I owned a Model T a while back and there was a time when the side walls of the 30x3-1/2 clinchers would crack after a season. There were also problems with air leakage because the rubber around the valve stem was not sealing to the metal of the stem. The quick fix was to loop a wire around the valve stem and twist-tighten it. Worked well enough, but the quality issue was still annoying.

When the clinchers were made in New Zealand or other responsible countries, they were fine. But that batch from Vietnam or Cambodia or China were awful.

--Scott

I think that if I were having this problem, I would mark the tire in relation to the rim, with a grease pencil or paint marker to determine if there is any slippage.

Hallelujah!

Installed a new inner tube & flap, marked the tire in relation to the tube and installed the 24" lock ring...

in less than one hour!!!!!

And without resorting to a single cuss word.

It took two hands, two feet, two ancient tire irons and two large screwdrivers but now I have the technique down. All the advice is correct, you just have to get in there and fail a bunch of times before, suddenly, everything snaps into place and you're a lock ring systems expert.

Next step - I'm going to slowly inflate and deflate the tire to ensure the inner tube stem is properly aligned.

Thank you, everyone, for your advice and guidance. The Franklin Club is the nicest group of people I've met.

I'm getting new tires for my '21 9B touring this spring. I'll try to produce a few YouTube videos on how to remove and install my lock rings.