Tire Pressure Again
I know this has been discussed before. I could probably figure it out from searching the forum but I am in a rush to prepare for my first camping trip. I am also in a rush since I am going into the tr...
Forum Discussion
I am the OP. Thanks, these responses help.
Backing up, coming from someone with zero experience. It seems that the deal is that the higher the weight I am carrying then the higher that the tire pressure needs to be. This would seem to make sense. The goal is to keep the tread evenly on the ground. With less weight on the truck the tires will bulge more so more road pressure will be on the middle tread. With less weight on the truck reducing tire pressure will flaten the bottom of the tire. But put more weight on the truck and that weight will push down on the tire putting more weight on the side tread, so you add more pressure get the tire back into the correct shape of tread evenly on the ground.
Then for a dually since there are double the number of tires on the rear end, the tire pressure should be lower on the rear end (for the same axle weight versus if there was only two tires) since there is half the weight on each tire.
Do I have this correct?
This is what the Michelin Truck Tire Data Book (the Tire Pressure Chart link in an above post) seems to be saying. I am looking at the Michelin Inflation Chart for Light Truck Tires chart 17" wheel diameter chart on page 22, which I believe is the correct chart for my E class Light Truck LT235/80R17E tires. As another Ram owner pointed out the Ram factory stock Nexen tires seem to have no tire pressure guide so he said to use this Michelin guide as close enough.
Then the other key hint in these responses is that the door stick is for maximum load. I didn't understand that before asking these questions.
Until I get to a Cat Scale to actually weigh the rig (or more specifically the axle weights) with the camper wet and loaded (so far I have not even had the camper wet loaded on the truck), I can waive my hands and say that the payload for my truck on the door sticker is 6,860 (higher than some configurations of the same truck because I have gas engine and regular cab both which save truck weight versus diesel and crew cab). From the truck camper actual weight (an official weight paper I got with the camper manuals) I expect my wet and loaded weight to be around 3,500. So I am 3,400 lbs BELOW max payload. Therefore the tire pressures on the door sticker are for more weight than I will be carrying. Therefore, the tire pressures on the door stick are higher than what I should be running.
So as someone said, the dealer saying 71 for the rear wheels when the door stick say 65 is absolutely in the wrong direction. Absolutely incorrect.
I am thinking until I get to a scale that I will leave the front tires at 71, which is below the 80 on the door sticker, but then I am nowhere near maximum GVWR. And I will take the rear tires down to the door sticker pressure of 65. Which is probably higher than I should be running.
I am pressed for time leaving on a 1,000 mile drive to Florida. Is what I say above a decent best guess until I get to a scale? Maybe I should go a little less than 65 psi on the rear tires?
I assume that lack of fine tuning the tire pressures before this 1,000 mile drive is not creating an unsafe situation. Rather, that the above will be close enough and it is more that if I don't correctly adjust that over the long term it will hurt tread life. And possibly the ride.
Does this sound ok? Does 71 in front and 65 in back until I get to a scale and fine tune sound at least safe if not optimal?
Then it seems that some people like to have more a little more pressure than the manufacturer charts, I guess for better ride? I don't understand that one. The truck rides better (possibly less bouncing around) with more tire pressure?
Backing up, coming from someone with zero experience. It seems that the deal is that the higher the weight I am carrying then the higher that the tire pressure needs to be. This would seem to make sense. The goal is to keep the tread evenly on the ground. With less weight on the truck the tires will bulge more so more road pressure will be on the middle tread. With less weight on the truck reducing tire pressure will flaten the bottom of the tire. But put more weight on the truck and that weight will push down on the tire putting more weight on the side tread, so you add more pressure get the tire back into the correct shape of tread evenly on the ground.
Then for a dually since there are double the number of tires on the rear end, the tire pressure should be lower on the rear end (for the same axle weight versus if there was only two tires) since there is half the weight on each tire.
Do I have this correct?
This is what the Michelin Truck Tire Data Book (the Tire Pressure Chart link in an above post) seems to be saying. I am looking at the Michelin Inflation Chart for Light Truck Tires chart 17" wheel diameter chart on page 22, which I believe is the correct chart for my E class Light Truck LT235/80R17E tires. As another Ram owner pointed out the Ram factory stock Nexen tires seem to have no tire pressure guide so he said to use this Michelin guide as close enough.
Then the other key hint in these responses is that the door stick is for maximum load. I didn't understand that before asking these questions.
Until I get to a Cat Scale to actually weigh the rig (or more specifically the axle weights) with the camper wet and loaded (so far I have not even had the camper wet loaded on the truck), I can waive my hands and say that the payload for my truck on the door sticker is 6,860 (higher than some configurations of the same truck because I have gas engine and regular cab both which save truck weight versus diesel and crew cab). From the truck camper actual weight (an official weight paper I got with the camper manuals) I expect my wet and loaded weight to be around 3,500. So I am 3,400 lbs BELOW max payload. Therefore the tire pressures on the door sticker are for more weight than I will be carrying. Therefore, the tire pressures on the door stick are higher than what I should be running.
So as someone said, the dealer saying 71 for the rear wheels when the door stick say 65 is absolutely in the wrong direction. Absolutely incorrect.
I am thinking until I get to a scale that I will leave the front tires at 71, which is below the 80 on the door sticker, but then I am nowhere near maximum GVWR. And I will take the rear tires down to the door sticker pressure of 65. Which is probably higher than I should be running.
I am pressed for time leaving on a 1,000 mile drive to Florida. Is what I say above a decent best guess until I get to a scale? Maybe I should go a little less than 65 psi on the rear tires?
I assume that lack of fine tuning the tire pressures before this 1,000 mile drive is not creating an unsafe situation. Rather, that the above will be close enough and it is more that if I don't correctly adjust that over the long term it will hurt tread life. And possibly the ride.
Does this sound ok? Does 71 in front and 65 in back until I get to a scale and fine tune sound at least safe if not optimal?
Then it seems that some people like to have more a little more pressure than the manufacturer charts, I guess for better ride? I don't understand that one. The truck rides better (possibly less bouncing around) with more tire pressure?
