tire pressure and valve stem issues

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Well I finally got around to going out to my RV in storage. Work has been crazy lately.

I went to get an oil change, had the fuel filter changed, and also had the differential fluid changed as the dif fluid was like sludge. While looking at the valve stem, the mechanic found a problem with my tire that I assumed had an issue with the valve stem.

The inside dual tire on the passenger side was almost flat and had a large nail in it. I needed a new tire because the large nail was too close to the sidewall. I had my two front tires moved to the back. One replaced the tire with the nail and one replaced a tire that had a cut in it from hitting a curb. The two fronts are the same tread wear and model (one year old Goodyears) as the other rear tires. I purchased two new tires for the fronts.

I also was able to confirm that my tire valves and extenders are all metal.

I plan on having the RV weighed during our next trip assuming I can actually find a weigh station open. They are always closed.

Until then, I am still guessing at the pressure. The tire guy at Firestone said according to his computer the fronts should be at 55 and the rears at 80. The sticker in the door says the fronts should be at 60 and the rears at 65. The Cruise America guy said that they keep them all at 80. So who the heck knows until I get it weighed. ????

How much should I expect to pay for the weighing? It seems in California they are always closed.

THANKS AGAIN!

Here is a quick check of the tires that truckers use. Rather than crawl under the rig to check the inside tire (assuming you do not have valve extenders) hit both on the tread with a hammer. They should both be at about the same pitch thump. If one is a dull thud instead of a thump indicating a low tire you will hear it. Also many truck stops sell a small club for this called a TIRE BUDDY. It is wooden with a metal weight at the end. When I was trucking and would pull into a rest area to use the john I would take a walk around the rig and thump all the tires(except the steering ). Then if there were any shady looking people hanging around I would keep the club with me while I used the john. The sight of the club will discourage any person with bad intentions.

Thanks for the responses folks!

Tire stems are a pet peeve of mine. The quality is just really bad these days, particularly on brand new vehicles. And slow air loss like you are seeing is the most common issue. You can try swapping just the Schrader core, but for my money, I would just get all the stems replaced with quality metal stems at a good tire shop.

No one here can tell you what pressure to run, since we don't know the weights, or even the tire you are running.

When I was in Elkhart last year I stopped by one of the tire manufacturers that supplies a lot of tires for trailer type RVs, and talked with them about getting some new tires for my previous campers. We talked about air pressure and he told me that trailer RV tires should be at max PSI at all times. Said that if you have a warranty claim and if asked what PSI they are run at and if anything other than MAX was listed they would deny the claim.

I would guess class C's would be a little different

I have an F350 dually. Recommended tire pressure is 75 for the fronts and 65 for the four rears. Just posting in case it helps you figure out your problem.

One question - What is the maximum air pressure stamped on the side of your tires ? I would also re-verify what the factory recommends.

The little valve stem core tool is cheap and you can probably find it at any auto store or Sears. There used to be metal valve stem caps that had the notch in the top so you could use them to check tightness of valve stems cores. Kind of lost favor I think because there was the fear that someone could use it to unscrew your valve stems cores and then toss them in the ditch. Hahaha ! KILL !

Personally, I run the tires on my truck and my fiver at the factory recommended pressure. I figure they know more about that then I do.

Re the loss of air pressure. Tires will lose AP naturally over time. And the time of day that you measure the pressure does matter. The pressure can be higher on a hot day, as opposed to measuring it early on a cool morning. And you shouldn't measure AP right after driving it as the reading will be artificially high.

As several others have said, go get your RV weighed, front and rear axles separately at least, then use a tire chart to determine correct pressures. I used to run 55-60 front and rear. Weighing/chart showed that I SHOULD have been running only 45 in the front. I dropped the front to 45psi, and the handling improved significantly.

I would think that 80psi in all tires is way to much for a small RV like yours. As suggested I would get it weighed and go from there.

In my small RV I am way under the max weight when fully loaded and have found that 80 psi makes it ride like a buckboard and handle poorly.

I have found that 65 psi in front and 75 psi in the rear is well within the specs for the weight and the handling and ride is phenomenal,checking the maintenance records that I got when I bought my RV from El Monte RV,that is what they kept them at when doing their service.

As for the loss air each time you check, your extenders may well be the problem as Ready To Go said, they will always leak and if they come loose they will cause a catastrophic air loss.

Instead of those I would replace them with a solid valve stem like the ones that I and many others have on their Class Cs.It makes checking and adding air a fast and almost painless chore.

Tire Man makes the best and the original ones and there are others on the market.

I have used 3 different types of extender. Each has created a flat tire for me. 2 tire venders have recommened not using them. One because I didnt have rubber stems, and the other because they wil come lose.
Free information ofr what it is worth.