Deerchaser

Now that I have stock sized terra grappler g2 e rated. What psi do you run unloaded vs towing a 5k travel trailer?

Thanks

jeffinthebag

Stock HDPP tires I run 55 front and rear non towing. With a load, air up to 80 as needed.
Read the specs on your tire.

atwowheelguy

What size tire? What does each axle weigh loaded and unloaded?

https://toyo-arhxo0vh6d1oh9i0c.stack...s_20170203.pdf

Deerchaser

Thanks, weight unknown at this time. 275 65 18

smokeywren

The correct answer depends on the weight on the tires. So you must weigh the rig at least twice, once with the wet and loaded trailer tied on to the wet and loaded truck, and once without a trailer. Divide the weight on the front axle by 2 to get the weight on each front tire. Divide the weight on the rear axle by 2 to get the weight on each rear tire. Then apply the load/inflation table for that size tire that atwowheelguy posted above.


The following is that table for your size tires:
PSI . Load
35 . 1940
40 . 2130
45 . 2310
50 . 2535
55 . 2640
60 . 2825
65 . 3000
70 . 3150
75 . 3305
80 . 3415


Your tires should say on the sidewall that the max weight on each tire is 3415 pounds @ 80 PSI, which agrees with the load/inflation table.


The above PSIs are the minimum for the weights listed. Add 10 PSI for long-distance high-speed towing, such as cruising on an interstate highway,.


So if the weight on your rear axle is 5,800 pounds, that's 2900 pounds on each tire, which requires a minimum of 65 PSI, and 75 PSI is okay for high speed driving.

atwowheelguy

Looks like 40 psi would handle axle weights up to 4260 lbs. That should handle any standard payload truck. Looks like 50 psi would handle even a maxed out HDPP axle GAWR at 4800 lbs.

What do the tire loading stickers show that come on trucks that are built with Load Range C tires?

I'm curious as to why a Load Range E tire is preferred on a F150 when a Load Range C tire will handle the weight of the heaviest GAWR on a HDPP F150 (4800 lbs.)?

I just haven't researched much about LT tires because I run P tires on mine. I tow a 6700 lb. camper with no problems. I run 35 psi front and 42 psi rear when towing. The P tires gain no load capacity beyond 35 psi, but the 42 psi just stiffens them up a little. 35 psi all around when not towing. Cushy ride.

atwowheelguy

Hey Mr. smokey. Please make sure that he understands that this was just an example of arithmetic and chart reading and that nobody should actually put 5800 lbs. on a F150 rear axle.

Deerchaser

Oh I got it. Looking at the p rated @ 35 psi for 2601 lbs, I adjust from there on my e rated. Unloaded will be set for 2600, loaded, Ill add 400 pounds until I get the rig weights.

smokeywren

Yeah, that just shows that those E-rated tires are overkill for that pickup. Those tires when pumped up to 80 PSI could handle up to 6,800 pounds on the rear axle, but the rest of the pickup would be crushed with that much weight.

Deerchaser

I know the tires are over sized for the truck, i get that, i knee it when i bought them. I wanted a heavy sidewall, stumps, rocks and less flex towing heavy. My rear axle is rated at 3800, front 3460. The oem wrangler fortitude ht suck. Sorry if you dont agree. Nevermind