Front tire pressure

Your Rig of this size should run 90-95 PSI in front and 95-100 PSI in back. These are average pressures for this size of motorhome.

noleakman wrote:
When they say to do your air pressure cold nobody seems to know if that is 40 or 50 or 60 or what ever depending on where you live and the elevation!

Cold means you haven't driven it and has nothing to do with ambient which could be 0 or 110F. Elevation doesn't seem to have any real effect, except for the adiabatic lapse rate that creates a temp. drop with every 1000ft. of rise. All this is just one reason why I always recommend a cushion of 10-15 psi over what the inflation charts say and a good example might be for driving out of Death Valley and up into Yosemite NP, where you're most sure to find summer snow at Tioga Pass.
Still, there are those that insist on following the inflation charts to the letter, but think nothing of these changes in temp. or a 200lb person moving about inside the coach. I mean who wants to stop and add or subtract air, as conditions change?

IMHO a tire pressure that works for some else might not work for you! I've been RVing since 1976 and I'm also a retired over the road truckdriver so I have knowledge of tires, but I'm not a expert. I have never weighed all four corners of my RV and I don't use the recommended tire pressure by Winnebago and Michelin on my RV, because it did not work for me! What I did do is experiment with tire pressures on my coach until I found out what works for me. My recommended tire pressure was 85 lbs. rear tires and 90 lbs. front tires. These pressures did not work for me due to rear tire squirm, and lower tire pressures cause more heat. What did work for me, and me only was 100 lbs. in all tires. I will admit that I get slightly a rougher ride at 100 PSI all around, but a great benefit that I received from 100 PSI all around was even tire wear and tire longevity. My first set of Michelins lasted 10 years with inspections, before replacing the tires. Change up your tire pressure every time you go out and keep notes about the handling and you will find what is right for you. Good Luck in whatever you decide to do!

noleakman wrote:
When they say to do your air pressure cold nobody seems to know if that is 40 or 50 or 60 or what ever depending on where you live and the elevation!

Actually it is widely known that "cold" means "at ambient temperature where you are BEFORE driving".

Look it up on any tire manufacturer's website-- they all say the same thing.

BTW, temperature makes a BIG difference in PSI, altitude, much less difference.

When they say to do your air pressure cold nobody seems to know if that is 40 or 50 or 60 or what ever depending on where you live and the elevation!

tropical36 wrote:
I'm thinking that any coach out there, requiring max sidewall pressure to support it's weight properly is in a bad need for larger tires.

Totally agree.

I'm thinking that any coach out there, requiring max sidewall pressure to support it's weight properly is in a bad need for larger tires. As for max psi with some of the older coaches running modern tires, keep in mind that the wheel itself mayme limited to 90 psi and would consider it downright dangerous for exceeding that number. I mean we're not talking the hospital here and more like the morgue, even though you seldom ever hear of a steel wheel exploding, while inflating.

Stim wrote:
When ever possible you need to set/adjust pressure when tires are cold/not driven.
Sidewall numbers are maximum pressure.

For Standard load/P-tires and XL/extraload/reinforced tires thats true and the pressure needed for the maximum load/maxloadpressure/reference-pressure is respectively 35 psi and 41 psi , so lower then that max written on sidewall.

But for C-load/6PR tires and up this pressure written on sidewall is that maxloadpressure// and the maximum pressure is higher .
Once concluded maximum pressure to be 1.4 times the maxloadpressure//.
And even stiff american TRA allows 10 psi above maxloadpressure/ for LT tires and ST tires, and even 20 psi above it for Truck-tires ( but when may we call it a truck tire, think from G-load/14PR).

so if the valves can stand the higher pressure , and mostly they do, you are even allowed to go over that maxloadpressure// written on the sidewall. Would give some extra reserve for peakloads for rear often needed. But for front not needed.

And that is what TS should first determine , if its only the pressure or if the suspension is at the silentblocks, as I suggested before.
But now I realise that it can also be at the other end , so suspension lifted to almost the top of it. The pressure part is cheap to chanche but needs some care that you dont go to low.

Read a topic on the Belgian camperforum. The man went to my country Holland Rotterdam to a company that did the suspension springs for also armoured cars around the world .
A long story , but weighed first per wheelposition and determined the hight difference R/L and from that data determined the new stronger springs to put on , and even R/L different. He was verry happy with it at the end. His suspension was also at the end almost against the silent blocks.
No bumping anymore.

Everybody will give you different information. My coach is 38'long and weigh's 29.5k. My tires are 22.5. 265x75. Toyo tires, and I run 100lbs in the front and 90lbs on the rear. Runs very smooth and the tire are wearing even.

When ever possible you need to set/adjust pressure when tires are cold/not driven.
Sidewall numbers are maximum pressure.