"E" Load Rated Tires - Air Pressure?

**pajeff02** · 10-08-2015, 03:44 AM

I just ordered and received tires for our '07 Suburban. As we haul our race trailer on a fairly regular basis (about 7,000 pounds loaded), I upgraded from an "SL" to an "E" load rated tire. The stock air pressure spec is 30 p.s.i. and I would usually up the rears to 35 p.s.i. and the fronts to 32 p.s.i. when towing with the "SL" rated tires.

What should I be running the "E" rated tires at both unloaded and loaded? Their max weight rating is at 80 p.s.i., not that I would ever go that high.

**0rion** · 10-08-2015, 09:47 AM

they're supposed to be ran at 80......I don't do that however unless I'm towing. I back mine down to 50 in between trips. Tires seem to wear decent there and the ride doesn't beat you to death as much. I would get a tire tread depth gauge and take some initial readings and then again after some miles and see how they're wearing.

**pajeff02** · 10-08-2015, 11:34 AM

Yowza! I just assumed that like most tires you could run the manufacturer's recommended air pressure no matter what the max pressure is. Good to know. Hopefully this doesn't piss off my TPMS.

**Whamhammer** · 10-08-2015, 12:05 PM

Originally Posted by pajeff02

Yowza! I just assumed that like most tires you could run the manufacturer's recommended air pressure no matter what the max pressure is. Good to know. Hopefully this doesn't piss off my TPMS.

I guess your sensor is actual tire pressure based, not comparison of each wheels revolutions (most of these are in hubs)? I had to drop the tire pressure of a new replacement tire on my moms Matrix about 4 psi, when she punctured the sidewall because of the tread height difference. That was a stupid design!

I wonder how much taller the tire height is going to be when you more than double the tire pressure as well?

**Firebirdjones** · 10-08-2015, 06:28 PM

Orion is correct, the E load range tires recommend that you run the max 80 psi pressure when towing. I have 2 trucks with E load tires and I practice the same psi with both trucks while towing. I do the same with the trailer tires as well.

What you don't want is pressure too low while towing, it creates a ton of heat and that's what makes tires come apart. Combination of too much sidewall flexing creating heat and riding on hot blacktop compounds that issue.

While not towing I run about 65 psi in the front and 60 in the back of both trucks and getting excellent tire wear like this with both Michelins and Firestones. I keep them rotated every 6,000 and adjust pressures accordingly each time they are rotated.

With so many people running aftermarket rims and different tire sizes, along with trucks weighing differently, I'd recommend play with tire pressure (daily driving-not towing) like Orion suggested and watch tire wear, and adjust accordingly.

**pajeff02** · 10-09-2015, 02:54 AM

Thanks, guys! Never had anything other than an "SL" tire on a vehicle so this is a new experience for me.

**douglowden116** · 10-09-2015, 03:35 AM

I would also make sure you run the metal valve stems the rubber stems don't take kindly to those higher pressures .

**Firebirdjones** · 10-09-2015, 05:37 AM

Excellent point Doug, I completely forgot to mention that.

Both of my trucks already had the steel bolt in valve stems. What struck me as odd is that the enclosed car trailer didn't. I switched that over to steel stems as well.

Jeff, you'll love the "E" tires first time you tow if you've only been on regular tires. You'll notice a huge difference right away in stability.

**Cutlass** · 10-09-2015, 07:11 AM

I run 50 psi up front and 80 psi in the rear while towing. Unloaded I run 50psi at all 4 corners, although I have run around 50f/80r unloaded. It's not too harsh with 1/2 ton suspension.

**pajeff02** · 10-09-2015, 11:00 AM

Our truck is equipped with metal valve stems as part of the TPMS stuff. Will probably mount the tires sometime next month, so the final tow home at the conclusion of the track season will be on the old tires. May have to wait until next year to see how these feel with a load.

**0rion** · 10-10-2015, 04:36 AM

Originally Posted by pajeff02

Our truck is equipped with metal valve stems as part of the TPMS stuff. Will probably mount the tires sometime next month, so the final tow home at the conclusion of the track season will be on the old tires. May have to wait until next year to see how these feel with a load.

Yep....i meant to put that in my last post. I've had tire places try to put low pressure stems in mine.

**DarrenWS6** · 10-19-2015, 05:28 PM

My Nitto Trail Grappler mud tires are the 10 ply E loads, granted I never tow, 45 psi is comfortable on them for casual driving around our county. Slats on the highway are more noticeable, especially when entering and exiting concrete bridges and pavement. I used to up them to 50 for highway runs but since I hardly drive it anymore I keep it to the 45 mark. My TPMS has agreed with it, however it is the outdated band style ( 2007 Ford ) and not the nicer newer ones. However they make the truck feel much more stable and controllable with the lesser amount of squish. I plus sized in height and width so I'm sure there are many influential factors compared to an OE size E load tire, but an E load on a heavy truck feels much better overall. My father's 2005 2500HD crewcab had 265-75-16 E load A/Ts on it, felt solid and controlled. So I can certainly imagine that while towing you will feel much better about the haul.

**Cutlass** · 08-01-2016, 12:47 PM

How are the E tires working for you Jeff?

**pajeff02** · 08-02-2016, 01:49 AM

Very well. I run around 50 psi when not hooked to the trailer. This past weekend, I used the trailer to move a friend and, since it was a fairly light load, just went to 60 psi. Definitely has a better feel going down the road than with the SL rated tires.

**Firebirdjones** · 08-10-2016, 08:49 AM

I had an interesting conversation with the front end guy I use, an old school mom and pop place. I had my duramax aligned before I made a recent cross country trip pulling the trailer. He noticed right away how the Michelins "feathered" the edges inside and out, which I knew. He told me he runs Michelins on his truck and they do the same thing, and every truck that comes in with these all terrain Michelins have the same issue. He feels it's the design of the tire. Even rotating mine every 6,000 miles had no effect.

He told me his cure was to run more air pressure and force the tire off the edges. He recommended running the Michelins at 75 psi at all times. Now I had already pumped them up to 75 for the towing trip. After I got back I decided to leave them there and see what happens. So far that has seemed to work. Now 5,000 miles later after rotating them it's not feathering the edges, and I haven't noticed excessive wear in the middle. I think the tire coupled with the 7,000 lbs. weight of the truck just likes more air pressure.

I also noticed an increase in mileage while towing. I only ran 60 psi before when pulling the trailer and never got better than 11 mpg on this same trip. At 75 psi (truck and trailer) This trip it got a very consistent 12.2-12.7 mpg. Pretty big difference just playing with air pressures. I also like how the truck feels when empty driving around town with more responsive steering input.

**pajeff02** · 08-12-2016, 03:20 AM

So far, the Generals are wearing very well on the Suburban at 50 to 55 psi cold. I haven't really check mileage as we have been short tripping it here and there with no real highway miles lately. Back when I installed them, it was "winter gas" time soon thereafter and checking mileage with that stuff is a waste of time.

**Cutlass** · 08-12-2016, 03:29 AM

I haven't had any issues with my Michelin AT2s but I have them on a 1/2 ton truck so that could be the reason. Also they are an older set (5 or 6 years old) so maybe something has changed on the newer AT2. I am gonna try running 75 psi on all 4 tires and see if I like it. They do seem to like to be pumped way up. With the fronts at 50psi, I still get a squishy steering feel. But then again, I'm used to running around on 22" wheels on my truck. Steering is pretty tight with those wheels/tires.

**0rion** · 08-12-2016, 07:23 AM

I've had mine at 70 for about a month since I towed the camper last and I'm towing it back home in a couple weeks.....just decided to leave them there for a month. It makes around town driving suck for me.....those things beat the piss out of you aired way up and running empty. I can tell a huge difference versus running 50.

**Firebirdjones** · 08-12-2016, 08:01 AM

Yep I did notice my truck rides a bit stiffer with 75 psi in the tires, but the steering response was so much better I decided to accept the trade off. It's not a handling truck, and feels very heavy when turning so every little bit helps there. It still doesn't ride all that bad when I compare it to 2 other trucks I drive.

My fathers 2014 3/4 ton is WAAAY stiffer than my 05 3/4 ton. I don't know what GM has done with those trucks but they tout having a stiffer boxed frame and other improvements. Boy that thing acts like it has no suspension on it. But it also turns better and corners more flat. When it's empty that thing rides like a tank compared to my duramax. He also runs the same Michelin AT2 tires and is keeping them at 75 psi at the moment.

My 79 1 ton isn't really stiff, it's more of a bouncy ride when it's empty. But the bench seat is also very cushy compared to a new truck so you tend to bounce in the seat. It also has an E load range tire and for the time being I've pumped them to 75 psi to see what differences it makes. This truck really doesn't ride any stiffer from what I can tell. But this truck also handles nicely, you can whip it around corners without feeling like it'll tip over, and has a factory rear sway bar as well (something my duramax doesn't have)

I'm contemplating the idea of buying an aftermarket rear bar to add to the duramax in an attempt to try and help the leaning in the turns.