Tire inflation

[Shoe2728]

Got E rated tires installed, 80psi max, Tire guy said it would be better to run around 65-70 psi as tires heat up. Always thought I should run max cold rating 80psi. FW weight is around 9000 lbs hooked up to truck.

[wilber1]

Just be aware that lowering pressure below sidewall lowers the load rating. An E rated tire at 65 psi has the same load rating as a D rated tire. So my question would be, why upgrade tires if you aren't going to take advantage of the increased load capacity and safety margin that goes with it? I would start at max and work my way down if wear is uneven but your tires will probably be age limited before they run out of tread.

[Slownsy]

Allen8106 you have a big proplem if pressure vent op 15 psi

[Dennis_M_M]

I don't think there is another subject on RV forums that generates more misinformation and pure guess work!

It is very simple:

1. weigh your rig - axle weights are fine, but individual wheel weights are better.

2. Find the weight/pressure chart for your brand and size of tire - they are all out there on the web.

3. Set your pressures cold according to the chart and relax.

4. Get a good tire monitor system for peace of mind if you are rolling up miles.

This is what Michelin says about RV tire inflation:
An underinflated or overloaded tire will build up more
heat that could go beyond the endurance limits of the
rubber and radial cords. This could cause sudden tire
failure. Underinflation will also cause poor handling, faster
and/or irregular tire wear, and can decrease fuel economy.

Overinflation, on the other hand, will reduce the tire’s
contact area with the road, which reduces traction, braking
ability, and handling. A tire that’s overinflated for the
weight it’s carrying is more prone to a harsh ride, uneven
tire wear, and impact damage.

[coolbreeze01]

allen8106 wrote:
I have a similar situation. I have a 5ver the weighs in at 10,500 unhooked. Now I haven't yet weighed the axles or the truck axles. I just upgraded from GY Marathons with a D rating to Maxxis with an E rating. My problem is that the aluminum wheel is supposedly only rated for 65 PSI yet the tires are rated for up to 80 cold. I just completed a 2000 mile round trip to Mesa, AZ and ran the tires a 65 PSI cold. I have a TPMS and observed that the tire pressure grew from the 65 cold to as much as 80 PSI running down the road on a day where the ambient air temp was 65 degrees.

I bet your rims wouldn't know the difference between 65 and 80psi and probably aren't limited to 65lbs in any event.

[allen8106]

I have a similar situation. I have a 5ver the weighs in at 10,500 unhooked. Now I haven't yet weighed the axles or the truck axles. I just upgraded from GY Marathons with a D rating to Maxxis with an E rating. My problem is that the aluminum wheel is supposedly only rated for 65 PSI yet the tires are rated for up to 80 cold. I just completed a 2000 mile round trip to Mesa, AZ and ran the tires a 65 PSI cold. I have a TPMS and observed that the tire pressure grew from the 65 cold to as much as 80 PSI running down the road on a day where the ambient air temp was 65 degrees.

[Cummins12V98]

rhagfo wrote:

Cummins12V98 wrote:

big bird 2 wrote:
I have heard all the opinions before and after going through a set of tires, I learned that "max air pressure is for the max load". If they are rated to 15,000 lbs. and you weight 15,000 lbs., then put in max pressure. If you have 12,000 lbs. then you should come down in pressure. The exact amount is not scientific, but if the tire says max pressure 50 psi and you are 10% below the max weight, then reduce air pressure 10%.
Go out for a day and look at the wear pattern of each tire. If it looks like you are wearing in the center come down 5psi, if the outer edge of the tire is wearing increase 5 psi. I have G rated tires and was running with 110 psi. A reputable tire dealer says that the tire can carry 20,000 lbs., you do not want 110 psi with a 13,000 lb. load. I am down to 80 psi and the tires show normal wear and less bounce.

Not all tires show load capacity in pounds. If your tires do not show pounds you may need different tires.

I ran my GY G's at 85psi on a RV that came with GY E's and it weighed about 12.5K the tread was perfectly even at many thousands of miles.

Chart said I should be running 80psi. Funny that is exactly what the E's were supposed to be ran at. Per GY Tech support they said to use chart but add 5psi when upsizing as I did.

Weight/inflation charts are there for a reason!

X3!

Dang Cummins, another member who understands that Max means Max, and less than Max, means lower psi, based on the percentage of load!!!

Lots of people call BS when I tell them I would get 120K with Michelins and over 100K with BFG's on my 98 2500 RAM 4X4. It's called proper inflation for the load!

[jadatis]

If you give al the right data of vehicle and tires I can calculate an advice pressure .

Tire pressure advice is all about load on tire and speed you drive with.
But for fifth wheelers and travel trailers you can go much higher in pressure without the screws tremble loose from the woodwork.
So if real weight is 10% lower then maximum load of tire, you better keep "maximum pressure"wich is infact not the maximum pressure of tire, but the pressure needed for the maximum load.

[cummins2014]

rhagfo wrote:

Cummins12V98 wrote:

big bird 2 wrote:
I have heard all the opinions before and after going through a set of tires, I learned that "max air pressure is for the max load". If they are rated to 15,000 lbs. and you weight 15,000 lbs., then put in max pressure. If you have 12,000 lbs. then you should come down in pressure. The exact amount is not scientific, but if the tire says max pressure 50 psi and you are 10% below the max weight, then reduce air pressure 10%.
Go out for a day and look at the wear pattern of each tire. If it looks like you are wearing in the center come down 5psi, if the outer edge of the tire is wearing increase 5 psi. I have G rated tires and was running with 110 psi. A reputable tire dealer says that the tire can carry 20,000 lbs., you do not want 110 psi with a 13,000 lb. load. I am down to 80 psi and the tires show normal wear and less bounce.

Not all tires show load capacity in pounds. If your tires do not show pounds you may need different tires.

I ran my GY G's at 85psi on a RV that came with GY E's and it weighed about 12.5K the tread was perfectly even at many thousands of miles.

Chart said I should be running 80psi. Funny that is exactly what the E's were supposed to be ran at. Per GY Tech support they said to use chart but add 5psi when upsizing as I did.

Weight/inflation charts are there for a reason!

X3!

Dang Cummins, another member who understands that Max means Max, and less than Max, means lower psi, based on the percentage of load!!!

Thats ONE thing I agree with cummins on. :B

[rhagfo]

Cummins12V98 wrote:

big bird 2 wrote:
I have heard all the opinions before and after going through a set of tires, I learned that "max air pressure is for the max load". If they are rated to 15,000 lbs. and you weight 15,000 lbs., then put in max pressure. If you have 12,000 lbs. then you should come down in pressure. The exact amount is not scientific, but if the tire says max pressure 50 psi and you are 10% below the max weight, then reduce air pressure 10%.
Go out for a day and look at the wear pattern of each tire. If it looks like you are wearing in the center come down 5psi, if the outer edge of the tire is wearing increase 5 psi. I have G rated tires and was running with 110 psi. A reputable tire dealer says that the tire can carry 20,000 lbs., you do not want 110 psi with a 13,000 lb. load. I am down to 80 psi and the tires show normal wear and less bounce.

Not all tires show load capacity in pounds. If your tires do not show pounds you may need different tires.

I ran my GY G's at 85psi on a RV that came with GY E's and it weighed about 12.5K the tread was perfectly even at many thousands of miles.

Chart said I should be running 80psi. Funny that is exactly what the E's were supposed to be ran at. Per GY Tech support they said to use chart but add 5psi when upsizing as I did.

Weight/inflation charts are there for a reason!

X3!

Dang Cummins, another member who understands that Max means Max, and less than Max, means lower psi, based on the percentage of load!!!

[Cummins12V98]

big bird 2 wrote:
I have heard all the opinions before and after going through a set of tires, I learned that "max air pressure is for the max load". If they are rated to 15,000 lbs. and you weight 15,000 lbs., then put in max pressure. If you have 12,000 lbs. then you should come down in pressure. The exact amount is not scientific, but if the tire says max pressure 50 psi and you are 10% below the max weight, then reduce air pressure 10%.
Go out for a day and look at the wear pattern of each tire. If it looks like you are wearing in the center come down 5psi, if the outer edge of the tire is wearing increase 5 psi. I have G rated tires and was running with 110 psi. A reputable tire dealer says that the tire can carry 20,000 lbs., you do not want 110 psi with a 13,000 lb. load. I am down to 80 psi and the tires show normal wear and less bounce.

Not all tires show load capacity in pounds. If your tires do not show pounds you may need different tires.

I ran my GY G's at 85psi on a RV that came with GY E's and it weighed about 12.5K the tread was perfectly even at many thousands of miles.

Chart said I should be running 80psi. Funny that is exactly what the E's were supposed to be ran at. Per GY Tech support they said to use chart but add 5psi when upsizing as I did.

Weight/inflation charts are there for a reason!

[big_bird_2]

I have heard all the opinions before and after going through a set of tires, I learned that "max air pressure is for the max load". If they are rated to 15,000 lbs. and you weight 15,000 lbs., then put in max pressure. If you have 12,000 lbs. then you should come down in pressure. The exact amount is not scientific, but if the tire says max pressure 50 psi and you are 10% below the max weight, then reduce air pressure 10%.
Go out for a day and look at the wear pattern of each tire. If it looks like you are wearing in the center come down 5psi, if the outer edge of the tire is wearing increase 5 psi. I have G rated tires and was running with 110 psi. A reputable tire dealer says that the tire can carry 20,000 lbs., you do not want 110 psi with a 13,000 lb. load. I am down to 80 psi and the tires show normal wear and less bounce.

Not all tires show load capacity in pounds. If your tires do not show pounds you may need different tires.

[N-Trouble]

A tire guy that doesn't know his stuff...

Rated PSI is COLD. Tire manufacturers already factor in PSI increase with temp.

[2-MTnesters]

Sandia Man wrote:
The tire engineers have already factored in the psi increase when a tire is running under such conditions. If it is an ST tire I would air them up close to max as they tend to perform better and not heat up as much. If these tires are LT tires they can be set to a psi commensurate to the load they are carrying.

X2

[Fishinghat]

The standard answer is to use the maximum air pressure noted on the side of the tire. Engineers design tires to handle the additional pressure from heating and altitude changes.

[Sandia_Man]

The tire engineers have already factored in the psi increase when a tire is running under such conditions. If it is an ST tire I would air them up close to max as they tend to perform better and not heat up as much. If these tires are LT tires they can be set to a psi commensurate to the load they are carrying.