Low tire

Topic: Low tire (Read 1604 times) previous topic - next topic

Low tire

March 09, 2020, 01:00:23 pm

Woke up this morning in Prescott to a very low (but not flat) 25psi tire. Fortunately it happened in a place that can fix such things. I suspect a failing valve stem or valve core. It was fine when we left Phoenix yesterday.

Re: Low tire

Reply #1 – March 09, 2020, 01:26:22 pm

Have whoever fixes it dismount and check it carefully.

Unless you have a TPMS and KNOW that it was not driven at lower than 10% below recommended PSI, it is considered a "run flat" and should not be used.

Re: Low tire

Reply #2 – March 09, 2020, 01:40:50 pm

So if it is considered a run flat condition on the front it is a no brainer. If on the rear the fully inflated tire has operated overloaded. TPMS are a wise investment for me at the cost of tires or coach damage from a failure. So good to hear that you found a low tire, not that you had a preventable failure.
Scott

Re: Low tire

Reply #3 – March 09, 2020, 01:52:21 pm

So after inflating to 95psi two hours ago. The pressure has not change one bit. I wonder if a bit of grit had the core stuck open just a sliver.

I'm going to have the tire dismounted and inspected for any damage.

I'm also going to ask if they have a TPMS system they can install.

Re: Low tire

Reply #4 – March 09, 2020, 04:26:08 pm

It may of leaked, but the valve cap is the secondary seal. I always run brass two piece valve caps on everything. I prefer the internal TPMS senders so I can retain the good valve cap. These are standard in the Aviation community. The single piece metal caps seal just fine and are available at any auto parts store. Not plastic.

Re: Low tire

Reply #5 – March 09, 2020, 04:30:34 pm

All of my leaks have been stem extensions or the stem retainer nut.

Re: Low tire

Reply #6 – March 09, 2020, 04:37:07 pm

That's why I won't run stem extensions as they are known to fail.

Re: Low tire

Reply #7 – March 09, 2020, 06:54:04 pm

Quote from: bigdog – March 09, 2020, 01:52:21 pm

I'm also going to ask if they have a TPMS system they can install.

You don't need a tire shop to install a TPMS. And you certainly don't need to PAY them to do it.

Pressure Pro, TST, etc. are all external, screw-on sensors that operate wirelessly. Get the package with enough to do the toad as well - very important to monitor the tow car tires.

Re: Low tire

Reply #8 – March 09, 2020, 07:02:22 pm

It was the stem. Specifically, It was the pictured red tip on the tire side of the long extension that came loose. The tire tech removed the extension and sprayed the short stem with soap. No bubbles. He then checked the tire pressure and resprayed it with soap. Bubbles then were found. The little red thing was jamming in the short stem causing an intermittent slow leak.

As the tire pressure was fine when we left Phoenix and 24 hours later it had lost 70psi. Or 2.9 psi per hour, Over the 4 hour drive we lost an estimated 11psi before shutting down. So right at the 10% limit.

The tire was inspected and no physical run flat damage or untoward smell was detected.

Re: Low tire

Reply #9 – March 09, 2020, 09:41:37 pm

Quote from: bigdog – March 09, 2020, 01:00:23 pm

Woke up this morning in Prescott to a very low (but not flat) 25psi tire. Fortunately it happened in a place that can fix such things. I suspect a failing valve stem or valve core. It was fine when we left Phoenix yesterday.

25 psi IS FLAT for a coach tire. Most tire manufacturers say thet 20% below pressure for the load is flat.

Re: Low tire

Reply #10 – March 09, 2020, 11:12:23 pm

Quote from: Roger & Susan in Home2 – March 09, 2020, 09:41:37 pm

25 psi IS FLAT for a coach tire. Most tire manufacturers say thet 20% below pressure for the load is flat.

It lost most of it's air over night while I was shut down. And I topped it up before ever driving to the tire shop.

The core at the small stem was leaking into the stem extension and was slowly leaking past the threads. So it was slow but steady. While I was driving it went down by an estimated 11 psi based on losing 70 PSI in 24 hours and having drove 4 hours after a tire check before departing Phoenix. However, (and I apologize for not remembering upon my first post) That inside tire was at 105 at the truck stop and was 5PSI lower than the other three rears. I drove the short distance to Prescott before calling it a day.

The tire shop inspected it and said it showed no signs of being run flat. I have no qualms about continuing to run this tire.

But I WILL be ordering a TPMS. How does everyone feel about the TST with flow through sensors?

Re: Low tire

Reply #11 – March 09, 2020, 11:40:29 pm

We has a TST system with flow through on the coach and caps on the toad. Black and white monitor monitor may be easier to see in some light. As I replace coach sensors I am going to the caps. Easy enough to remove and without any sensors (flow through) adding air is much faster.

Re: Low tire

Reply #12 – March 09, 2020, 11:50:49 pm

Quote from: Roger & Susan in Home2 – March 09, 2020, 11:40:29 pm

We has a TST system with flow through on the coach and caps on the toad. Black and white monitor monitor may be easier to see in some light. As I replace coach sensors I am going to the caps. Easy enough to remove and without any sensors (flow through) adding air is much faster.

And the B&W is a bit cheaper.

Re: Low tire

Reply #13 – March 10, 2020, 12:02:24 am

Supported stem extensions with the rubber pieces in the rim holes reduce the chance of leakage greatly

Re: Low tire

Reply #14 – March 10, 2020, 07:16:16 am

BigD,

You can also get rid of the extensions on the inside duel and install a one piece valve stem. Yes they make one that is that long. We have had them on both our coaches with duel wheels. Look up the Beico # VH515S8C On the stem they are just a 515S8 These are what we run at a lot more reasonable cost. Here is a pack of 10 that some members can share if everyone will get together. VH515S8C Duallyvalve Chrome Stem 8-1/8in. Qty/10 Shop around as prices vary greatly.

Mike

Re: Low tire

Reply #15 – March 10, 2020, 09:01:34 am

Quote from: Pamela & Mike – March 10, 2020, 07:16:16 am

Shop around as prices vary greatly.

Mike.

I agree - even at the same supplier!

Your link to the pack of 10 shows a price of $428, or $42.80 each.

The same outfit lists a single stem for $27.64 each. The 10-pack price seems a little HIGH.

VH515S8C Duallyvalve Chrome Stem 8-1/8in. Qty/1

Re: Low tire

Reply #16 – March 10, 2020, 09:40:14 am

This isn't cheap but if the ones above are indeed
$42.80 each then it's in the ballpark

Dually Valve Stems for Motorhomes with Alcoa Aluminum Wheels with 1.5" Hand Hole - DL4AC - Always Shiny Wheels and RV
Dually Valve Stems for Motorhomes with Alcoa Aluminum Wheels with 1.5" Hand...

Re: Low tire

Reply #17 – March 10, 2020, 10:10:51 am

Several tire manufacturers recommend replacing the tire if it has gone flat while parked. I assume that means flat on the ground. 25psi on the front tire may have escaped that but think it's a good idea to check the tire for any sign of bulges, etc when stopped for fuel or food. Tire shop inspection can't see any hidden damage. Driving at 25 mph will heat the tire from flexing. How much is anyone's guess.

Pierce

Re: Low tire

Reply #18 – March 10, 2020, 10:42:30 am

I think the TST would be a good addition to any vehicle,toad,trailer. Hard to second guess tire condition. If in doubt change it out. You seem confident that it's good and you will own the results. Myself and everyone else would make their choice and also own it on there tires. I'll admit I have tires that are +twenty years old and look like crap. 1922 Model T. But if they fail I'll be fine with results. TPMS would be a good option on the T also, but I'll be fine. The temperature indication is also quite helpful to me. Always watching and seeing temp change. Anytime it's over 140 deg I slow down and watch closely. This only happens for me at max GVWR and excess speed with high outside temperatures. Adjust as necessary to prevent. Great tool. IMO
Scott

Re: Low tire

Reply #19 – March 10, 2020, 11:32:01 am

Lots of Corona virus doom and gloom here.

Just to make it clear.

I did not drive on a tire with 25 PSI.

I should not have posted my story until I had an answer as to why my tire was so low that morning. And also later after posting, remembering that I had checked them at the pilot only 35 miles from our stop in Prescott. Once again, I apologize for the lack of detail because of my faulty memory. The 25PSI tire was just 2psi lower than the others on the drive axle at the fuel stop. The pilots air hoses had no pressure. So went to Prescott and would make pressure adjustments in the morning when the tires were cold. Only to find that tire at 25PSI the next morning. Seems that the red tip that was discovered later had jammed the valve core when I checked the air at the pilot fuel stop, creating a slow leak. When I aired up that low tire. 2 hours later it was still at full pressure.

Bottom line, This tire is fine. I will drive on it with full confidence.

TPMS will be added to my coach.

Re: Low tire

Reply #20 – March 10, 2020, 12:04:13 pm

I learned a short technique many years ago that may have some value. I did it religiously on big trucks running lots of days near 80,000#. If your checking tires with a gauge and have your air hose handy, after getting your reading satisfactory, put the chuck back on the stem and give it a blast of air then put the cap on. This helps to assure nothing on the seat of the valve.

As always, FWIW.

jk

Re: Low tire

Reply #21 – March 10, 2020, 01:12:54 pm

And some offshore tire gauges damage the valve core so they constantly leak. I had one that way when checking on the road. The moment I took the gauge off, it starting leaking. Fortunately, I had a metal cap and that sealed it until I could buy a few valve cores. Nice to have the valve core tool or a valve cap with the slot.

Pierce

Re: Low tire

Reply #22 – March 10, 2020, 03:09:51 pm

I've had a Schrader valve stick open when checking tire pressure and whacked it with the gauge to re-seat it.

Re: Low tire

Reply #23 – March 10, 2020, 07:35:05 pm

The straight long Chrome Duallyvalves are for steel inner wheels. If you have dual Alcoa wheels you need the DL4AA kit.

DL4AA Chrome Duallyvalve Kit

see ya
ken

Re: Low tire

Reply #24 – March 10, 2020, 08:02:45 pm

Quote from: kenhat – March 10, 2020, 07:35:05 pm

The straight long Chrome Duallyvalves are for steel inner wheels. If you have dual Alcoa wheels you need the DL4AA kit.

DL4AA Chrome Duallyvalve Kit

see ya
ken

Good catch Ken. That along with the TPMS is a must order for the Bigdog coach.

So far in my coach ownership. I have had a bent core that flattened a tire, An extension that nearly came off, And the issue from Sunday that let my air out.

Affiliate Notice