Tire Loading/Inflation

[navyblue]

The Goodyear tires (all 6) on my Winnebago Voyage say 95 PSI @4080 lbs. Is this the maximum OR minimum PSI? The plate on the inside drivers side door says 92 PSI @ 4080 lbs. Same question. Coach has been weighed (3) times and all (6) tires average 3400 lbs load on each tire.
The Goodyear website says since my tires were manufactured after 2/28/06 the following are the PSI at various weights

Single: 80 PSI @ 3640 Duals: 80 @ 3415 PSI
85 PSI @ 3740 85 @ 3515
90 PSI @ 3890 90 @ 3655
95 PSI @ 4080 95 @ 3970
100 PSI @ 4190 100 @ 4115

My average weight on each tire DOES NOT even equal the minimum weight. The front axle rating is 7500 lbs and rear is 13,500 lbs. Should I be at 80-85 lbs PSI per tire or leave it at the 95-100 I run at as I tow a 4,000 Toyota Tundra.

Thanks/NAVYBLUE

[madrone]

I believe in running the inflation pressure stated on the door. You cannot "average" the weight across an axle, you should run the pressure required for the one with the
most weight. Usually people weigh individual tires so they can attempt to balance out the load by moving things around in the RV. Running lower than called for tire pressures leads to more tire flex (nicer ride) but more heat buildup in the tire increasing blowout risk.

[madrone]

It looks like tire specs are slightly changed since your RV was built, inflate to the 4080lb spec (95psi)

[Steve Ownby]

If there seems to be a conflict between the inflation information from the coach manufacturer and the tire manufacturer, always go with the tire maker. The inflation listed in the tire inflation table is the minimum pressure required to carry the listed weight.

If your tires are all carrying the same weight of 3400 lbs then you are over the rear axle maximum of 13,500 by 100 lbs. Just be aware that in its current travel configuration you are operating at the design limit of your rear axle assembly. I assume you are towing 4 wheels down so you don't have any hitch weight to worry about. Since you have about 600 lbs of unused axle capacity in front, if you can move some cargo forward it would help balance the load.

As to your question of whether or not to adjust your air pressure, I would stick with 90-95 lbs all around. Remember those are the minimum pressures required to carry the weight. If one end of your axle is significantly heavier than the other you might need a little more pressure. At some point you should try to get your 4 corners weighed.


Steve O

[navyblue]

Thanks to all who replied. Little clarification. The rear tires are loaded at about 3,300 lbs per tire and the front ones at about 3,450 giving me 300 lbs leeway on the rears and 600 lbs on the front. This is full tank of gas, me and the missus, empty black/gray and 1/3 fresh water tank. I was towing a Toyota Tacoma empty(4,080 lbs with 1/4 tank gas). I moved 300 lbs of wood, hiking gear, camping gear, etc that was in the rear 1/3 of coach to covered truck bed. This is gear we use to camp up in desert country out west were we can't take the coach.
With all this in mind I think I am going to let the 100 PSI that is in all (6) tires slowly decrease to 95 PSI and stay there as I would rather be a little overinflated than under

NAVYBLUE

[Hooligan]

Average has nothing to do with the inflation pressure. The inflation pressure on the sidewall is the maximum weight and pressure for that tire.
Weigh each end of each axle. If the front is 3700 on one side and 3200 on the other (Average 3450) set the tire pressure the same in both front tires to carry the higher load. (85psi single, 3740#) If you can balance the load it will "normally" improve handling.
Don't go less than the minimum pressure specified. (If your front weight was 3450 equally on each side, 80 psi would be the minimum to use)
Going to the maximum pressure gives a harder ride. and reduces the tread contact because the center of the tread balloons out, and at at less than 80psi the center of the tread could lift up.
Many people recommend going 5psi above the calculated pressure to provide a safety margin... Experiment- My tires (22.5 inch) minimum for the rear weight is 80 psi but that "feels soft", at 90 psi I have a good ride and no wallow.
Pressures are set when cold, they will be higher when the tire is hot, just don't reduce air pressure to try to compensate. Don't exceed max rim pressure.

FWIW, I use an infrared temp gun to check tire temps at each stop on the road. I look for any tire that is significantly warmer, and that could indicate a problem.

navyblue, this started as a short reply, turned into a sea story... hope it helps.....

[daellishou]

I am also rather new with a MH and I was concerned about this same issue. The tire manuf. may have different recommendation. My MH has Toyo tires and so I checked their website. They have a very clear and specific recommendation; "Inflate to the minimum pressure recommended by the MH manuf." In my case 105 psi. That is what I am going to do. The actual weight of the MH is only needed to insure that you are not exceeding the GVWR not to adjust inflation pressure. I understand that some people don't see it this way and you have to make your own decision. As I you and others said; we need to be worried more about underinflation rather that getting a softer ride.

[Ernie n Tara]

What Hooligan said!!
Ernie
PS Pressures will rise as much as 8-10 PSI when the tires are hot (seems to depend on moisture content in the air). Leave them until they cool before setting pressure.

[Gary RVRoamer]

Quote:

"Inflate to the minimum pressure recommended by the MH manuf."

That's the lawyers talking, not the engineers. Toyo got caught up in a nasty lawsuit over RV tires that were under-spec'd by the RV manufacturer, so they want to make it clear that the RV manufacturer is the responsible party.

By the way, Toyo was exonerated in the tire lawsuit - the RV manufacturer was found to be at fault.