Wanted to get some opinions out there. When towing a moderately heavy load (7500-10,000lbs), what pressure do you you run the rear tires on the TV at? The manufacturer rating for the TV, sidewall max, or somewhere in between?
I have my F250 tires set a 80 psi...which is the max cold on the sidewall of the tire...my fifth wheel loaded around 9,500 lbs ...last Saturday i took the truck out of the garage..hitched up ..and overnight the air temp had dropped to 18 degrees.. 6 am Sunday morning...after going down the road for 5 miles the tpm light went on ...my tires had a pressure reading of 60lbs.. I.had to inflate all 4
2014 Crusader 325 TE....2012.. F 250.. Supercab XLT, 4x2 , diesel....days camped 2011 ... 28.... days camped 2012...115 ... days camped 2013...155...2014...171 and counting
Just curious why you would run the max recommended on the tire vs what the TV manufacturer has on the sticker in the door for the max tire pressures? My F250 has a max of 65psi for a gvwr of 9600lbs. However I have seen others with the 10k gvwr have higher recommended pressures and my 08 Ram 2500 megacab had 60/70 for an 8800lb gvwr. I believe the tire sizes have something to do with this as well as the Dodge had 265 70 17's LRE (rated at 3195lbs max at 70psi 3005lbs) and the Ford has 275 65 18's LRE(rated at 3415lbs max so at 65 psi are rated for 3000lbs). So it would seem size matters in this case. Granted nothing wrong with running the tire makers max but just curious why you would if we practice what we preach and keep our TV well within it's ratings then the safe numbers the TV manufaturer provides should easily be with spec to haul our loads.
I have Michelin tires and this is what they have to say.
Using my GMC Sierra 2500HD with Duramax diesel engine SRW as an example.
Door post sticker:
LT 245/75R/16 tires (MAXIMUM PRESSURE 80 PSI Cold Inflation Pressure)
front - 60 PSI (supporting a load of 2480 pounds per tire) 4,960 pound axle
rear - 80 PSI (supporting a load of 3042 pounds per tire) 6,084 pound axle
The maximum GVWR is 9300 pounds; not 11,044 pounds.
My actual weight (NOT TOWING)
Front Axle - 4160 (or 2080 pounds per tire)
Rear Axle - 3600 pounds (or 1800 pounds per tire)
To support the actual load according to the attached Michelin recommended tire pressure (truck not towing) the front should be 50PSI and the rear should be 40 PSI.
If pressures are at door sticker 60/80 the truck is a beast on rough roads, skidding and bouncing to the point control can be lost easily on washboard roads (especially on a down hill slope).
I typically run 55/65 when not towing as that gives me a reasonable ride and handling, though I still get a pretty good bounce out of the rear.
When towing my 5th wheel camper, ACTUAL AXLE weight:
Front: 4180 pounds (or 2090 pounds each tire)
Rear: 5100 pounds (or 2550 pounds each tire)
Using the chart, 55 PSI still works for the front (I run the recommended 60 PSI anyway) and the rear at 65 (Michelin recommended) but I run at 70 PSI which provides me with a safety margin yet limits "chucking" and bouncing that I see at 80 PSI.
As you can see, 60/80 is "safe" for the maximum GVWR of my truck (9300 pounds - including the maximum axle loads front and rear). A different pressure set up works much better for me since I know exactly the load on each of my tires towing and empty.
You of course can run anything you please, but you asked why I don't use the pillar pressures and this is my logic.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW