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04-04-2010, 10:04 AM
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#1
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Montana Fan
Join Date: Feb 2010
Location: Calgary
Posts: 351
M.O.C. #10119
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Tire Air Pressure Questions
My truck tires are - Bridgestone Duravis LT265/70/R17 Rated "E". Weight rating is 3135 lbs and max tires pressure is 80lbs. The sticker on the truck door states the tire pressure should be Front - 60 lbs and Back - 72 lbs. When driving the truck without the 5th wheel I use 60lbs in the front and 72 lbs in the back. When I hook up the 5th wheel with a hitch pin dry weight of 1965 lbs should I be filling the tires to 80 lbs, or still use the 60 for the front and 72 for the back?
I'm kind of wondering about the 80 lbs max tire pressure. Is the 80 lbs suppose to be the cold tire pressure, or is that the max tire pressure when the tires are hot? I'm kind of wondering about this 80 lb tire pressure for my 5th wheel tires, because a tire shop guy told me to put in about 75 lbs in the 5th wheel tires and they will heat up to 80 lbs.
I would greatly appreciate input that will allow me to use the correct amount of air pressure so that I don't put my tires at risk of blowing out.
Thank you.
David
__________________
DPAM
2017 GMC Denali diesel, crewcab, 4x4, regular box.
2010 Montana 3150RL- Moving to Montana Package , Hickory Edition Package, wet bolts
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04-04-2010, 10:50 AM
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#2
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Montana Master
Join Date: Dec 2006
Location: corning
Posts: 694
M.O.C. #6635
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The panel inside the door is the cold tire pressure the manufacturer has selected for the best performance of your truck with the tires it originally came with. My truck states 55 front and 80 rear.
Those numbers are for cold tires. The 80psi max number stated on the tire side wall is for cold tires. The tires will increase in psi while driving but that is factored into the cold rating.
I hope that helps some.
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04-04-2010, 01:47 PM
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#3
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Montana Master
Join Date: Sep 2006
Location: Casa Grande
Posts: 5,369
M.O.C. #6333
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David, If you know the actual pin weight of your trailer AND the actual axle weights of your tires you can go to the Bridgestone site and check the recommended tire pressures for your tires and weights. Look for the tire and loading charts. I have the Goodyear G614's, on my trailer, which are rated for 3750 lbs each at 110 psi. I don't have that much weight on the tires so I don't air up to max pressures. Hope this helps somewhat...
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04-05-2010, 03:42 AM
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#4
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Montana Master
Join Date: Aug 2007
Location: Waterford
Posts: 3,693
M.O.C. #7500
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I run the rears at 60 when empty so they wear more even and don't beat me to death. When loaded, they go up to 75. I found out the hard way that 80 psi even when poaded was too high and wore the centers out of the tires.
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04-06-2010, 04:57 AM
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#5
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Montana Master
Join Date: Aug 2004
Location: Cedar Rapids
Posts: 4,876
M.O.C. #1944
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dpam, If you look closely, all tires have a psi rating "COLD" which means that's the maximum tire pressure the manufacturer recommends. This allows for pressure buildup when traveling. These tires will go up to around 95 psi when traveling. Don't exceed the maximum recommended "COLD" pressure.
Orv
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04-06-2010, 11:04 AM
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#6
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Montana Master
Join Date: Apr 2009
Location: Murrieta
Posts: 5,816
M.O.C. #9257
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I have been taught that the tire pressure must only be read when cold (not driven). I have also read and been told that you can drive up to one mile at low speed and still be able to get an accurate cold tire pressure reading (seems like the distance to get to the nearest service station to air up the tires in case they're low). After that distance the reading could be affected because the air pressure changes with temperature changes caused by driving, the weather temperature, the road types and other factors.
I will also reinforce that one should know the actual weights of their TV and RVs as these can help determine what tire pressures should be and if you are exceeding anything.
Your door pillar describes 72 PSI (cold pressure) and if you have not changed out the tires and the tires maximum weight rating is 3,135 at 80 PSI, look at the RAWR on the door pillar and it is probably around 6,000 lbs or less or 3,000 lbs or less per tire. If you had the air pressure table for that Bridgestone tire, filling the tire to 72 PSI will probably match the weight requirement for your truck. If you go higher than that, then you risk overinflating your tires and experience premature wear in the middle of the tires like what Tom S. described.
Admittedly my truck specifies 75 PSI. My tires have a 3,195 lb weight rated at 80 PSI. Since my RAWR is only up to 6,000 inflating my tires to 75PSI will support 3,000 lbs on the tires. I have gone over than that (because my trailer is at 80 PSI and I forgot to use 75PSI for the truck) and I was able to catch it before the center of my tires exhibited excessive wear.
When I am not towing I reduce the PSI on my truck to 65 PSI so the back end doesn't bounce around as much and there is no weight back there. I have gone lower than 60 (55-60PSI) to soften the ride even more, but the outsides of the tires start to wear and the fuel rating drops. So my sweet spot when not towing is 65psi. The 75PSI on the pillar typically is the maximum loaded requirement unless otherwise stated. My Mercedes Benz has the unloaded and loaded PSI on the pillar. Since I rarely drive by myself I keep it at max because the MPGs are very good at that measurement.
Your truck will vary. I hope we have provided enough information for you to determine what will work for you. But try not to exceed the weight ratings at any point of your rig (tires, wheels, axle, gross, TV, Rig, and combined) and watch for the wear signs and you should be okay.
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