Tire Inflation

[Mikeg]

Ok. I'd love to hear some thoughts about this. I've read a lot about tire inflation and such when towing. Every one has different opinions. My truck is an 09 Dodge Ram 1500 Crew Cab 4X4 Laramie with the 5.7 Hemi. Tire size on it is 275/55/20. The door plate says 35 PSI for front and back tires. Once winter is over, I will be putting on a summer/all season set of tires, same size, max PSI is 50, the tires are Motomaster A/T2's if that makes a difference. I tow a travel trailer, trailer itself weighs 4350Lbs. So, once loaded up, lets say I am towing around 5500Lbs, I do use a weight distribution hitch. Now, my question is, need I bother exceeding the PSI of 35 or meet in the middle and inflate em to say 44 or 45 or inflate them to the max? I towed in previous years with a Dodge Dakota, same weight, but a lot less truck and sorta wondered why the tires on it were showing so much wear, I never gave any thought to tire inflation. Anyway, thanks a bunch.

[sideout1961]

I inflate mine to 45. Not real comfortable inflating to max. I would also like to hear other opinion on this. The max on my tires is also 50.

[Herk7769]

Even a rudimentary search will turn up hundreds of threads on this topic.

http://www.forestriverforums.com/for...ure-30579.html
Like this one.

There were over 20 that used the title "Tire Pressure" alone.

[PHS79]

Being that they are a P-metric tire I would go to the max psi while you are towing. P-metric tires usually only have 2 plys (some may have 3) on the sidewalls even though the tread area probably has 4-6, so they ride nice. Where as LT tires have the same number of plys from bead to bead, usually 6 plys for load range C - 8 plys for D - 10 plys for E. LT tires will ride rougher when empty but they handle weight much better (night and day difference).

On my F150 I run LT325/60/18 Nitto Terra Grapplers that are a load range D and can handle 3000lbs at 50psi. I run 45 psi front and rear all the time, doesn't matter if towing/hauling or running empty.

[Mikeg]

Thanks PHS. The tires are rated for 2800Lbs each, way more than I'll tow on four tires. Although, The tires are listed as light truck and not passenger, but after trying to research them a bit more, I think they may be P rated, I'll need to look at them some more, although I don't think it'll change my mind on them. they're rated very good and they are made by Cooper. Thanks again.

[Helmsey]

On mine I use the weight chart to determine what pressures I put my tires at. I don't cross the scales every time I tow, but I have a pretty good idea of what I weigh based on what I have packed and previous trips to the scales with that setup. If something changes drastically (wife packs more than normal) I will hit the scales as soon as I can get to get the axle weights and adjust tire pressure accordingly.

[acadianbob]

Originally Posted by PHS79

Being that they are a P-metric tire

I wonder if they aren't LT tires as I don't believe there are any P-metric tires that are rated for 50 PSI. On the Canadian Tire site, the sizes look like they are all LTs. If 50 PSI, they are likely Load Range C.

So, assuming they are LTs, I would use the manufacturer recommendation unloaded and I'd use Max Rate PSI when towing. It's cuts down on heat generation from flex. And less flexing means a firmer but less bouncy ride.

My F150 has LTs from the factory. It wants 40 psi on the sill plate so that is what I run until I'm towing and then it gets 50 psi.

If you are switching from P to LT, remember to get steel valve stems.

[PHS79]

After doing a little more research and looking at the canadian tire site, the 275/55/20 has a XL designation. Which means that it is actually a P-metric tire but with the XL means that it is has extra load (where the XL comes from), and has a higher weight rating along with the higher psi rating. But with that being said I would still run the max psi when towing, it shouldn't have as much sidewall flex as a standard P-metric but will still have more than a LT tire will. Just my $0.02 worth...

[Mikeg]

thanks so much for the input. Appreciate it. Now, where the hell is spring???