Forum Discussion

mikestock's avatar
mikestock
Explorer
Apr 19, 2015

Tire pressure for 275/80R22.5 LR H tires

I'm sure this has been a topic many times in the Class A forum. I have been searching for quite some time but can't find a recommendation, even in the manual. Running 6-275/80R22.5 load range H tires and know the max psi recommendation is 120 psi. I am coming from a heavy 37' fiver with load range E tires and always ran them at the 80 psi max.

I just purchased 6 new Continental tires and the installer recommended running them at the max, 120 psi, but this guy has more experience with commercial trucks than RV's. They are mounted on a 40' Phaeton with no unusual loading. I had them set at 105 psi but would like some input from others with experience in load range H tires.
Class A
  • tropical36's avatar
    tropical36
    Explorer
    Apr 19, 2015
    mikestock wrote:
    I'm sure this has been a topic many times in the Class A forum. I have been searching for quite some time but can't find a recommendation, even in the manual. Running 6-275/80R22.5 load range H tires and know the max psi recommendation is 120 psi. I am coming from a heavy 37' fiver with load range E tires and always ran them at the 80 psi max.

    I just purchased 6 new Continental tires and the installer recommended running them at the max, 120 psi, but this guy has more experience with commercial trucks than RV's. They are mounted on a 40' Phaeton with no unusual loading. I had them set at 105 psi but would like some input from others with experience in load range H tires.

    As said over and over again, at least weigh each axle and use the tire inflation chart for your size. I always add 15 - 20psi for all the variables and can't see how one could remain anywhere near correct throughout their trip without doing so.
    Having said that and as an added note, modern tires on some of these older coaches have a max psi rating that far exceeds the wheel rim max and would consider that dangerous, pumping them up to max. and above the wheel psi rating.
  • Vulcan_Rider's avatar
    Vulcan_Rider
    Explorer
    Apr 19, 2015
    Every vehicle made for the US market since about 1970 is supposed to have a sticker or placard somewhere with the recommended tires and pressures.

    Look:
    Inside all the door jams.
    Inside the glove box or other storage areas around the cab.
    If you do end up contacting the manufacturer, also ask them where the card is supposed to be.

    Just because you upgrade the load range of the tires (this may not apply to you), that doesn't necessarily mean that you need to up the air pressure.....at least not much.
  • walker760's avatar
    walker760
    Explorer
    Apr 19, 2015
    Have a 2006 40QSH Phaeton and the owners manual says to keep the pressure at 110 LBS. Michlin tires... Hope this helps
  • wolfe10's avatar
    wolfe10
    Explorer
    Apr 19, 2015
    Absolute best answer is to weight it and use Continental's inflation table to determine the minimum acceptable PSI for your load. Perhaps add a little as a fudge factor.

    But, until then, IF (big IF) this is the OE size, you can look at your GVWR sticker to determine the correct PSI assuming all axles are loaded to their GAWR.

    Sure hope that is over-inflated, but sure safer than under-inflated.
  • kg1d_dx's avatar
    kg1d_dx
    Explorer
    Apr 19, 2015
    go to the manufactures web site and it should have a chart for the tire. I have weighed my RV when it was loaded and I Run 100 psi in front and 80 in the read. You need to weigh each wheel position to get the proper load info. I am sure if you run 120 psi it will give you a hard ride.
  • RayChez's avatar
    RayChez
    Explorer
    Apr 19, 2015
    I think 120 lbs for a forty foot coach is too much. Mine is two feet shorter at 38' and I run on them 100 lbs. I like the way it rides and have never had any blow outs in 60K miles.

About Motorhome Group

38,708 PostsLatest Activity: Mar 03, 2025