MTFCA Forum

Awhile back I went out to my barn to work on the T and found the left rear tire flat. I removed the demountable rim and took it to my local tire shop where they found the valve stem had been cut on the side! Their theory was that the beads of the tire allowed so little space that the tire itself cut the stem. See photo one.

I decided to check all the tires so I put the car on jackstands and took them to the tire shop. While the tires sat at the tire shop another went flat for the same reason.

We replaced the two damaged tubes and checked the others. The tire shop ground a little of the bead off where the stem went thru which I hope will fix the problem.

When I went home just for fun I dragged out and old tire and guess what I found? (Photo two) Someone 30+ years ago had the same problem and came up with the same solution Something to keep in mind if you use rubber stemmed tube. If I ever need any more tubes I'm going to buy them with brass stems or pull a "Jelf" and replace the damaged rubber stems with brass ones.

Your first photo looks more like the valve has been torn around the circumference of the tube rather than the two sides where the tire would clamp onto it.
That is how the valves look when the tire and tube have rotated in the rim due to low pressure not being able to wedge the beads into the rim.

Drive or brake and the valve has to go with the tube around the rim so rips it out.

Tim, I agree with Peter as to the cause of your failures. If you measure the width of the rim at the widest point of the bead and then measure the width of the two tyre beads and the valve stem, I will be flabergasted if the total is more than the width of the rim, especially with the skinny little beads on the rubbish tyres available today.
The "need" to notch the beads is to overcome poor mounting techniques. If one side of the tyre is fitted first, and then the tube is fitted inside it, the bead already fitted gets pulled towards the fitter when trying to get the valve stem inserted through the rim, thus blocking the valve stem hole in the rim. That's when the notches are "needed". If the tube is fitted inside the tyre and both beads of the tyre are fitted at the same time, there is no need to notch the beads at all.

Hope this helps,
Allan from down under.

I have done the notch technique for 40 years. I am surprised this appears unusual to some in the hobby.

Dick, notching the bead is not unusual, it's just unnecessary. Done hamfistedly, I have seen it lead to a broken tyre bead during tyre fitting.

Allan from down under.

OK - to answer your questions.
1.) The tires are Universal T-Drivers. The tubes are Hartfords. They had 2200 miles on them when the trouble started.
2.) The tire stems were cut / torn on one side not fore and aft which I would have expected had the tires slipped on the rim. I'm going to put little paint marks on them to monitor for any slippage.
3.) I maintain all tires at 65 psi.
4.) I have disc brakes on the rears but have never had to apply the brakes more than moderately.
5.) I had the tire installation and removal done by a tire shop that works on a wide variety of car, truck and agricultural tires. These were the first Model T demountable clincher tires they worked on but now they've had them on and off twice
6.) Flaps are installed in each tire.
7.) I will ask whether the tube was fitted into the tire before being installed.
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I just heard from the great folks at Chaffin's reminding me of the importance of accommodating the larger diameter valve stems on today's tubes. This may require enlarging the holes in the rims and even the felloes to allow for a little wiggle room. The stem will expand slightly when inflated and if pressed tightly into the rim is another setup for possible failure.

As you appear to still have rubber valve stems you more than likely will still be in trouble in the future.
The main failing of the rubber valve stems is they are only marginally capable of withstanding the high pressure needed.

They only have a small vulcanised seal around the top of the inner stem. The air can easily force its way up around the metal stem and burst through the seal.

When you are driving is the time it is more likely to leak, just a small amount of air loss and the tire and tube can then slip around the rim.
You haven't mentioned if you are able to change a tire yourself, if you are driving you might have to change the tire on the side of the road, so you need the tools to do this as you won't be near anyone who may be able to help. The video link posted elsewhere is fine but you won't have access to a table and some of the equipment on the road.

This photo shows a rubber valve stem which I cut open when I was in Canada on a tour, it was ripped out as described above. Being in a foreign country travelling alone I had to do a quick fix which was to buy small hose clamps to clamp around the stems.
Now the Kamper is back in Australia and 9 years later the tubes are still holding air. I am getting to old to change tires unless I have to so the rubber stems stay clamped until something fails (which I hope is never but know they probably will sometime)

Peter - thanks for your comments. You make an interesting point. Yes, I can change a tire. I carry a spare, jack, lug wrench & etc. I also frequently check tire pressure.