Wednesday, September 27, 2023


RV Tire Safety: Leaking valve stems – Does your tire dealer know what it’s doing?

By Roger Marble

I recently got this question from a reader:
I just replaced 6 235/80R 22.5 XRV Michelin tires on my 2013 Monaco Monarch Class A Motorhome. The dealer installed balancing bead bags and new valve stems. I have good access to all valve stems now and have an aftermarket TPMS [tire pressure monitoring system]. A couple of the rears were below the 95-pound alarm point when cold and I decided to add air.

“When I removed the TPMS sensors, the valve stem seats leaked on three of six tires. I replaced the faulty valve stem inserts, completed pressure checks and all is well. I heard from one of my friends that the bead bags are causing the valve stem seat to fail and I understand there are redesigned valve stem seats that solve this issue. Can you comment?

I responded:
The dealer that installed the “balance” stuff should have also installed the special valve stem/core air filters. Powder from beads can get into both the core and the TPMS sensor and make them malfunction.

Bolt-in valve stems have a rubber insert on the air chamber side and a large metal washer on the outside. There is a torque spec on the bolt-in valves. This blog post covers valve stems of different types and has the torque spec for the bolt-in nuts.

By “stem inserts” do you mean the valve core? Every valve stem I have ever seen comes with a new core. The only reason for them to leak is some “stuff” got into the new core and most likely was from the balance stuff.

This makes me wonder if the dealer was just interested in selling you the balance beads but didn’t want to kill the sale with an increased cost for the valve air filters; OR he didn’t know that filters were needed when you put “stuff” inside a tire.

Also, did the dealer give you a written tire warranty that covered the use of the balance stuff?


Read more from Roger Marble on his blog at or on


Roger Marble
Roger Marble
Retired Tire Design and Forensic Engineer w/50+ years of experience. Currently has Class-C RV. Previous Truck Camper, Winny Brave, Class-C & 23'TT. Also towed race car w/ 23' open trailer and in 26' Closed trailer. While racing he set lap records at 6 different tracks racing from Lime Rock CT to Riverside CA and Daytona to Mosport Canada. Gives RV and Genealogy Seminars for FMCA across the USA. Taught vehicle handling to local Police Depts


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3 years ago

At the risk of sounding stupid…but at the same time wanting to learn, what are balance beads? You’re not talking of the pieces of lead they put on the tire, are you?

Roger Marble
3 years ago
Reply to  PennyPA

No. “Balance beads are more like ceramic BBs. Theory is that the beads disperse around the tire once you are moving and “balance” the tire.

Regular “balance weights” clip on the wheel or some use double sided tape. These weights use to be lead now sometimes made of steel

3 years ago

I had the same problem on my class A after putting new tires on. The installer didn’t change the valve cores and I had problems with each tire when I tried to check air pressure. I tried using the compressor to blow the cores clean but that didn’t help. I was on a long summer trip and stopped at a tire store that said they had the filtering cores that should have been installed. $60 later I left thinking I was good to go. Then trying to air up a tire I found the same problem with the cores leaking. I fought this for some 11000 miles until I got home. I took the RV to a local tire store, had them dismount all the tires and clean them out thoroughly and spin balance the tires with steel weights. Haven’t had a problem since.

3 years ago

I had issues with those balancing beads 10 years ago on my 2006 jeep Wrangler when I got new tires! As an off roader i usually drop my air pressure for more traction & a better off road ride! I noticed that after a couple of times the air was coming out very slow & also slow in going back in! I also had one of those air deflators E-Z Deflator. Come to find out that the beads (very small. like powder) was causing a blockage So for me it wasn’t a leak, but an issue with airing down/up. My answer was to just pull the core valve & be done with it. The next time I got new tires I opted out for the beads.

Roy Frazier
3 years ago

As a seller and user of balancing beads, yes, sometimes beads can get under the valve core and cause air to escape after removing the valve cap or TPMS Sensor. Usually, a blast of air from the air chuck to inflate will blow the stem clean without further problems. I have had beads and sensors on my Class A for four years without problems after following this procedure.

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