With the camper on I run 90-100PSI in the front and 100-120 in back depending upon whether I am towing or not.
Without the camper I drop the pressure to 65-70PSI all around. I've never had any issues at all, but personally I wouldn't run 'em much lower than that.
You should be inflating to the load. They increase pressure as they heat up and make the ride to hard. Check what they are rated for in pounds of truck axle weight. Then put all tires on same axle at the pressure the heaviest side calls for. That requires you to take it to the scales. Usually the tire put on by factory is rated just above the maximum the truck can weigh full. Drop pressure no more than 10% of the maximum pressure. Therefore 90 PSI can go as low as 81. That's cold, as then when it heats up it goes to probably 86. When you increase load in truck, then you will want to increase tire pressure, as needed.
I run about 110 on mine - I am generally loaded with the camper at all times, and the few times I don't I figure it's not worth airing them down at all. It is a stiff ride but what the heck, it's a big truck and I don't mind it much. That's what air-ride seats are for
I weighed the truck with camper on at one of the highway weigh stations here in Oregon and use the manufactures tire pressure chart. Tire max is 110#, I run 95# rear and 85# front and air down to 70# unloaded. Instructions from Rickson say not to run below 70#.
I have moved the tire pressure up and down on my tires, with the truck unloaded. I found that the only difference to me, with my truck, was the hassle of airing up and down. I guess I am just not as sensitive to a soft ride as most people are. My wife says she can not tell the difference either. I leave mine at 110 PSI, with or without the TC.
I do change pressure in the air bags, 5 PSI empty, 50 PSI loaded. I also change pressure in the Rancho shocks, #1 or 2 empty and 7 or 9 loaded.
BHale wrote: How much pressure do you run in your 19.5's? I'm at 90(factory pressure) now in my 08 4500 and i'd like to soften the ride a bit.
Thanks!
Brian
The factory pressure is for the max weight rating of your axles. I drive an F450 at work, and run the tires at 80 psi at its loaded weight, which is the recommended pressure for its axle capacities of 6000 front, and 11,000 rear. Your 4500 has higher axle capacities, therefore the 90psi, but as said earlier, you should inflate to the weight being hauled. If you do a fair amount of driving unloaded, I'd drop them to 70 psi, which is the lowest pressure recommended for the 19.5's, then air up when hauling your camper or whatever load you have. Even with your camper on the truck, you might not even need 90psi on the rears, because you may not even be close to the trucks 12,000 rear axle rating.
Rich
'09 Dodge/Cummins 6.7 3500 Quad Cab DRW SLT Laramie Auto, Timbrens & Overload Bump Stop Spacers; Tork Lift Super Hitch, Tiedowns and Fastguns, ExtremeAir 12 Volt Air Compressor
'04 Arctic Fox 990; 91 Jeep Wrangler ARB's TeraLow 4.5" Rubicon Express Lift
I get very little weight transfer to the front axle so I leave it at 70 psi up front all the times. I air up to 100/110 psi rear when loaded. 70 psi front/rear unloaded is pretty smooth IMO, but I also have adjustable Rancho's so that may be helping too. If your 19.5 are brand new it takes a few miles for them to "settle in" for what ever reason, but it does make a difference in how mine rode after some miles.
2000 F-350 7.3L PSD Super Cab 4x4 SB SRW 2006 Lance 861
(Slideout, Solar, Gen, etc.)
Air Bags/In Cab Cntl, XL 9000's,
Roadmaster Sway Bar, Rickson's
I think each tire manufacture has a high and low pressure for each tire they make. Not all tires of a given size are the same. I suggest checking the specs on the tire you are using, for the proper tire pressure.
For the Michelin 245/70R19.5 XDE® M/S LRH, used as SRW, the recommended pressure varies from 75-psi (3390 pounds load capacity per tire) to 120 (4940 pounds load capacity per tire). DRW is different.
There are two versions of the 225/70R19.5's. Thave different pressures than the 245s and are different from each other.
Keep in mind, this is for the Michelin tires. Others may or may not be the same.
Wayne
* This post was
edited 11/07/09 07:38pm by Reddog1 *
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