Westlake 215/75R17.5 H air pressure?

[sh1pper]

Anyone know what the load rating for 110psi would be? I know that the max load rating is 4805 at 123psi which would handle 19,220# (far exceeding the axle ratings of 16,000#). Actually I would like to know how low I could safely go to improve the ride. Any suggestions appreciated!

[GOTTOYS]

In my opinion this is not going to change the ride by much if at all. That is controlled by the suspension. Lowering the tire pressure also lowers the load carrying capacity of the tire. They put those 17.5s on there for a reason. Keep in mind, not all the weight is carried on the axles. Approximately 20% is pin weight which is carried by the truck.

[racer4]

You could see if this info helps:
Tire Inflation Tables


Another source of info:
http://www.rvtiresafety.net/

[sh1pper]

Originally Posted by racer4

You could see if this info helps:
Tire Inflation Tables


Another source of info:
RV Tire Safety

Thanks! I found a couple that had 17.5 tires and they had the same load ratings.
I have never seen an instance where lower tire pressures didn't give a better motorized ride. I would expect the same for a towable, but no one is usually riding in it to confirm...

PS: 110psi = 4330# x 4 = 17,320#
100psi = 4010# x 4 = 16040#

[jtesta1]

If you lower the air pressure the sidewalls will suffer from the lack of pressure support. It may ride smoother but the flexing of the sidewalls could lead to broken belts and tire failure.

[emm-dee]

Originally Posted by jtesta1

If you lower the air pressure the sidewalls will suffer from the lack of pressure support. It may ride smoother but the flexing of the sidewalls could lead to broken belts and tire failure.

Some of our real tire experts will have to respond about pressure vs sidewall life. But, lowering pressure will definitely result in less side to side stability.

[BandJCarm]

Tireman always says that 'blowouts' or whatever he officially calls them, are the result of underinflated tires.

[spock123]

On my Goodyear’s, G614 it says 110lbs but I normally run 100lbs.

[sh1pper]

Originally Posted by BandJCarm

Tireman always says that 'blowouts' or whatever he officially calls them, are the result of underinflated tires.

It would seem to me that "under inflated" should refer to the load that the tire is carrying. If a tire manufacture has a chart showing lower inflations for lower loads, then the tire should not be under inflated at that load. The maximum psi on the side of the tire doesn't mean that the tire would fail at lower inflations unless they were over loaded. I am sure that at some point tire flex and heat would negate lowing the pressure too far even if the load warranted it.

[jtesta1]

Get a piece of wire and keep bending it and what happens. It will eventually fail. That's what happens to the steel belts in an underinflated tire. Air pressure creates strength by not letting the sidewalls flex .That's the reason China bomb tires fail , they lack sidewall strength and people over stress them by turning to sharp and bending and stressing the sidewalls

[W5CI]

I would run the recommended tire pressures, You can always have the MORRyde IS suspension installed and I guaranty that will give you a smother ride. also Get a TrailAir hitch is you don't already have one.

[sh1pper]

Originally Posted by W5CI

I would run the recommended tire pressures, You can always have the MORRyde IS suspension installed and I guaranty that will give you a smother ride. also Get a TrailAir hitch is you don't already have one.

I have a 2017 Ford F350 that has a maximum tire pressure of 80#psi. Ford recommends 60# in front and 80# in rear for GVWR. The tires are 18" E rated and have 400# higher load rating than do 16" E rated tires with the same maximum psi. The Cedar Creek has 17.5" H rated tires which far exceed their 80% of 18K GVWR. There is no recommended tire pressure just the maximum tire pressure of 123#. From the load charts I would guess a recommended range should be between 100# and 110#, but that's just IMHO.

[llr]

i agree with running the recommended pressure, for stock tires that would be from the inflation stickers from the manufacture, for other tires that would be the load inflation charts or slightly higher for a safety margin.

in TT the the stock tire max pressure is general the recommended pressure as they typically but on the lowest rated tire they can.

[BandJCarm]

IMHO, the recommended range is equal to the max range. One is not less than the other, if you want tire life.

[sh1pper]

Originally Posted by BandJCarm

IMHO, the recommended range is equal to the max range. One is not less than the other, if you want tire life.

You must have missed my example of Ford's recommended tire pressure.

[llr]

hopefully one of the tire experts will chime in, they have recommended to use the charts before. there would not be load charts and max pressure on tires if they were actually designed for max, it would be inflate to XX.

My current TT uses MAX PSI, when I change the tires I will go to a higher LR. the higher LR will handle my weight at the same pressure but can handle more, i will probably run 5PSI higher on the new tires mainly because all 4 tire are probably no carrying the exact weight so I want a little margin.

I don't think I have ever owned a vehicle that the recommend was the max

[Boatdude62]

I have a 2017 F350 Dually....75 in the front....65 rear. Run 105 pressure in 614’s on CC 36 ckts. Never any issues.

Installing new 614’s today.

Would like to upgrade camper hitch type a shock absorber type. I’ve heard they make the ride much improved.