For highway driving, Is it better to run E rated tires at lower pressure (for comfort) or D rated tires at proper pressure? I am finding that most tires over 285 are rated E (especially Mud Terrain tires).

 

Almost all 37s are load range D and at least a couple are C. Plenty in the 35" area that are D as well.

You don't want to run a low pressure. You do want to run the right pressure for the tire, which is lower than factory the larger you go. So say a load range D 35" would probably be run around 28 psi. Or whatever it takes to get the contact patch right.

Load range E just means stiffer sidewalls. Air pressure shouldn't really be much different when properly inflated. The tires will be stiffer than a D. Load range E are generally target at full size trucks. Work great on a Super Duty.

Some people run E and say it's fine. If you have a pig if a JKU, you may be fine. They ride bad enough as it is, so personal opinion is the skip the E.

 

Just did a quick tire search in the 35" range. Most any tire I hear of people buying, are load range C and D. What tires are you looking at?

 

Here is what I am looking at:
Nitto trail grappler 285 75 17 - load range E, heavy tire from what I read
Nitto trail grappler 285 70 17 - load range E
Cooper discoverer STT - load range E
BFG KM2 - load range E

I want to stick to 33 1/2 to 34" range. Not ready for 35s, I just installed a 3" lift so I can go a little bigger...I was just asking the general question because If I go wtih E rated, most seem to run it with lower pressure to help with the stiff ride. I wondered if this would generate too much heat and cause the tire to wear faster. Still not seeing many at load range D or lower, except the goodyear MT/R.

 

here is what I can tell you from personal experience. I have had 2 wrangler 4 doors. I have run e rated toyos on both and if I get a 3rd it too will run e rated toyos. first one was a 13 sport with 16" stock tires and wheels. I switched to toyo 245/75-16's at2's and it rode as well as the stock good year 225P tires. a while later I switched to 285/75-16's E rated Toyo at2's on different rims and they too rode great. Next I get a 14 jkur and switch to Toyo AT2 in 285/70-17 E rated on stock rims they ride better then stock BFG, then I get new rims and 285/75-17 AT2 Extremes and they too ride great and then move up to 35/12.5-17 AT2 Extremes and they ride great. I also have a set of new Cooper AT3's in 275/70-17 in C 's that I have for winter driving and they ride the same as my E rated Toyos. What is the secret? E rated tires can be run at 26-28PSI with no issues at all. I did a test running to Moab on two different occasions. First time I pumped my tires up to 35psi for the trip down and back and the next time I ran them at 26-28psi and mpg was essentially the same both times. Toyo has a load rating sheet for different PSI's on their website and I think the mistake peole make who complain about e rated tires riding rough is too much psi. That all said I have done the chalk tests several times and every time my tires show perfect psi anywhere from 16psi to 32psi so I don't have much stock in the chalk test. I go by rode feel which is comfort and handling. That along with Toyos chart shows that for me and my vehicle 26-28psi is perfect. My jkur weighs 5040 lbs without passengers as weighed on a scale with full tank of gas.

 

E rated tires are designed for work vehicles carrying payloads and towing. Not a jeep. I wear 315/70/17 Hankook Dynapro MTs(measure out to 34") in the spring/summer/fall and they're a load range D. General grabbers AT2S 295/75/16 load range D in the winter because of the laws up here and both ride fine at 28-30psi. Stick with load range C/D unless you get a kick out of spinal surgery

 

You guys are making my point, One guy basically says the rating doesn't matter because he has had several different brands and was able to air down for comfort and handling and maybe a chalk test.... then another guy points out "E" are for heavy duty trucks and way too extereme for jeeps and have fun with the spinal surgery...

I do know that for Daily driving, if you air down for comfort an "E" rated tire, then it will be too low and generate heat and I would think this would cause the tire to wear alot faster. I agree with running "the correct pressure" for the tire.

 

airing down to 26-28psi is not going to cause any issues in fact if you check tire pressure by how it is supposed to be checked ie the 10% rule you will find that 26-28psi is the perfect psi.

 

You air down to the point the contact patch is even. Not more so the ride is soft.

315/70/17 is 34" and less in terms of rolling radius. When I had those in the Duratrac, I had to program the Jeep as 33.5" tires for the speedo to me accurate. Those were load range C.

Or, listen to the guy who has only had load range E. Sounds pretty unbiased. Odd thing about humans, they tend to like what they have regardless of the actual value.

 

I have had P rated, C rated, D rated and E rated. Been driving since 1971 so have had my share of tires. Goodyears, Coopers, BFG, Toyos, Dunlops, Michilins, metzlers, you name it I have had them lol. What I do know is what works for me.