Tire Pressure for G Rated Tires

Cummins12V98 wrote:
Per GY Tech Support when up sizing. Weigh each tire with RV fully loaded. Use the weight/inflation chart then add 5 psi. Better ride better tire wear better braking.

I ran 85 psi on GY G's thousands of miles with perfect wear.

That is what the inflation charts are for.

Don't believe me call GY Tech support.

This is exactly true, weighing each wheel position will give you the numbers you need to utilize the weight/pressure charts. Without knowing what every tire position is carrying your only going to be guessing as to the correct tire pressures needed to carry the load safely. Just because that tire is designed to have a cold inflation rate of 110psi,that can then carry 3,750lbs that may not be the correct tire pressures for your situation.

Per GY Tech Support when up sizing. Weigh each tire with RV fully loaded. Use the weight/inflation chart then add 5 psi. Better ride better tire wear better braking.

I ran 85 psi on GY G's thousands of miles with perfect wear.

That is what the inflation charts are for.

Don't believe me call GY Tech support.

I have the Sailun "G" rated tires on my triple axle toyhauler. I've weighed all my wheels separately and have around 2000 lbs. on each, with 2 of them at 2500 lbs. The Sailun have very stiff sidewalls, if you sit on an unmounted one it barely flexes at all. I run 95-100 psi in mine simply because I'm hoping for a bit less jouncing around due to the stiff sidewalls. I've had them for 3 years and around 12,000 miles and they still look and ride great.

If your goal is to give yourself the greatest payload capacity (margin of surplus capacity) then you should air at 110. This gives you the max capacity of the tire...hence the greatest margin of safety.


I have never understood upgrading a tire and then downgrading its capacity by decreasing air pressure...not on a heavy fifth wheel anyway. There are too many unpredictable road forces at play. My 2 cents worth...

If I calculate it with my determined extra save formula, I will come to 101 psi advice .
Then I assume the ST tires where yust enaugh to carry the axle load.
And your new G rated 3750 lbs AT 110 psi.
For the 3450 lbs maxload of the ST tires calculated with no reserve back the pressure for the new tires.

This is higher then the 80 psi AT-pressure of the ST tires, but these are calculated in maximum load for more deflection allowed.
If you would keep the ST tires they better also been kept at higher pressure then 80 psi , to give same deflection a LT tire of same sises would have, lesser heatprocuction so better for tires.
Most tiremakers did allow 10 psi extra above AT-pressure, nowadays not anymore in America. Europe still allows it.

But for you with the G rated not an issue anymore, only write it to explain the higher pressure needed then you would expect.

And this is only to compare, already is adviced to weigh.
Best per wheel( pair) , second best per axle, but as long as you did not do that , give the GAWR and GVWR ( gross axle/vehicle weight rating) , then I will calculate for that with a reserve I think is best, assuming you dont overload , as you stated already.
also give number of tires and axles of Trailer, and maximum speed you wont go over for even a minute.

Misyudging of the weights is more rule then exeption, so even though you think not to overload, weighing might prove you do.

Bayley wrote:
OP....you don't need to go to another web site to ask a question like this. Your question has nothing to do with Montana 5th Wheels.
I have the Goodyear G614's on my 5'er and I always run 110 psi in them and have had no problems at all. 110 psi is what is recommended while towing for safety and performance.

Agree...wondering if the dealer confirmed that your wheels would handle the extra air pressure?

2016 Montana High Country 370BR GVWR 15,200#

Air the GY G614s up to 110# (COLD)

I keep my G614's at 110 psi. I'm 12,500 on the axles but know the kitchen/entertainment slide is heavier haven't weighed side to side.

My G rated tires a aired to 110 PSI. I want the extra capacity/margin that 110 PSI provides
I suggest the OP do the same. After a few trips check to ensure the tires are wearing evenly across the face of the tread.

I wouldn't assume the dealer knows anything.
I think the new HC has 8 lug wheels, so you may be ok. But just me, there is no way I would air up to 110 until I looked for a load or psi rating on the backside of the wheel.
Go weigh the rig all loaded up.
Probably 3100 on the pin and about 8800 on the axles loaded heavy.