Load E vs C

I've recently started running my Cooper at3-xlt's around 30psi for on road comfort. I used to run them closer to 40psi, but it's so much less bumpy/jarring @ 30psi. I'm considering a LR C tire for my next set, rationale being more on road comfort without having to go so low on pressure.

What do you guys think with regard to on road scenarios? Better to run LR E at lower pressure or go LR C at higher pressure? I would air down for off road with either tire.

 

There aren’t many c rated tires available unfortunately. Its basically p rated or E. C would be plenty if they made them

 

What size tire?
C load with 3 ply sidewall is your best happy median if you only see light to moderate off-roading and mostly pavement.

Mickey Thompson Baja Boss is likely the best with that option in a number of sizes.

 

35" (or equivalent)
BF Goodrich has the KO2 in a 315/70r17 that is C rated. I think Toyo also offers the open country AT3 in a 35" variant with a C load rating. I'll look into the Mickey Thompsons.

I'm not necessarily opposed to the E rated tires but on road comfort is becoming more important to me as I get older If I can air down an E rated tire and not suffer any negative wear from doing that, that would be fine with me. As stated in my OP I've just never run my E tires this low for any extended period of time so I don't have the data on tread wear at low pressures.

 

I agree that the C load rating is plenty for a 1/2 ton truck like the Tundra. I think the "heavy duty" advantage of an E rated tire for this type of application is overstated.

 

I don’t know, man. Seems like you tow a lot. LR Es help a lot with stability. Thicker sidewalls for better protection when aired down off road. I chunked some of the lugs off my Duratracs on Imogene Pass. I’m not sure I would have made it if I had the stock Michelins. Granted, they’re P rated. But going places like that with less sidewall isn’t something I’m super interested in. And it seems that every C rated tire I look at still weighs about the exact same as an E.

For me, if I’m going to have roughly the same weight penalty anyway, I’m going to stick with E. I’m also on the TRD Fox suspension for the TRD Pro model. It rides super soft and smooth, and LR E tires don’t feel so bad.

I’m curious if you will still think you need to go to LR C tires when you’re finished installing your coilovers and UCAs.

 

Good points.

I'm curious how things will feel after I install and dial in this whole suspension. I'll definitely finish that install and get some miles on pavement and dirt before I make a tire purchase. Just gathering info for now.

Does anyone have any experience of bad/uneven tread wear on E rated tires that are running a lot of pavement miles at lower pressures?

 

I've got close to 40k miles on 285/75R18 Duratracs on my '21 Tundra. The truck has almost 42k miles on it, so they've been there since nearly the beginning. I run them at about 45 psi when unloaded on pavement. I guess that's low considering max is 80psi? That seems to be the sweet spot for comfort and fuel economy anyway. I rotate religiously (every 3k miles) with no uneven wear.

 

Good info. I've rotated these pretty religiously, as well (every 5k miles), and have gotten pretty good mileage out of them. I think I'm around 45k or 50k miles currently, probably have another 5k-10k miles in them but they're definitely showing their age.

I'm finding these coopers comfortable around 30psi (unloaded) on pavement. At that pressure the center of the tread patten has a sunken or convex appearance to it. Seems like at low pressure this could be problematic. I'll see if I can snap a pic.

This is what I'm ultimately concerned about: Running a LRE tire at low pressure on pavement for the sake of comfort, at the expense of shitty tread wear.

 

Yeah, I think 30 is probably too low. Any psi that makes LR E tires feel like SL or P-rated tires is probably too low.

 

Not sure if I fully captured what I’m talking about but here’s a photo.

 

I'd do the same thing with that fleet. But I only have the one truck that serves all purposes including towing and off-roading. I haven't tried C, granted, but with the softer suspension setup I have, my E tires have served me well. I ride 45 psi on pavement and 18psi off.

My main hangup with C is that I understand them to have weaker sidewalls than E yet it seems they weigh about the same as E in the same size.

 

I have E rated Nitto TGG2's on my Tundra TRD Pro and it's not bad compared to my E rated Toyo RT's on 5th Gen 4Runner with King 2.5's. My Runner feels like a race car even with the compression backed off, almost fully. I will get C loads for the runner when the time comes.

 

Regardless of load rating running any tire with the improper pressure will result negatively in not only tread ware but in the tires proper performance.
Will it cause a catastrophic, likely not, but a possibility.
You’ll be replacing tires more often, manufacturer is likely not going to honor a treadlife warranty, and your tires will not perform as well as they should. This includes braking and handling.
So these are things to think about.

 

Yeah 30psi with stock tires does not equal 30psi in an e rated. You need more pressure to run flat contact patch.

Interesting there is at least a falken wildpeak in C rating offered in stock size now.

 

My thoughts are leaning this way, as well. Raptors come stock with a 315/70r17 C tire and they perform great. I just don't see the need for the E rated tire on a 1/2 ton any more, especially since they ride so rough.

 

This is what I was thinking. There has to be a downside to running such a low pressure.

 

Look at a load chart. I believe it works like this.

say a P rated tire holds 2k lbs at 30psi.
Say an E tire holds 4k lbs at 75psi. It doesn’t necessarily hold 2k lbs at 30psi because the P can

 

Right. The load rating isn't what I'm concerned with, though. My truck (and just about any 1/2 ton truck I can think of) runs out of GVWR/payload long before individual load index ratings of C, D, E or any other LT tire tire is reached.

It seems to me that a properly inflated C range tire (like a BFG KO2, for example) will wear, perform, and ride better on pavement than an under inflated E rated tire. Some are probably saying...uh, yea Marv, welcome to the party

Until a few months ago, I never really gave much thought to the implications of load ratings. I was blindly in the camp of getting an E rated tire because "I tow sometimes and therefore I should have the heaviest-duty tire available because it's better..." There's a lot of people out there who still subscribe to this school of thought and I'm not saying the E rated tires don't have merit with regard to towing performance. But when it comes to the specific category of ride comfort and off road performance, I think the C rated tires may actually be the better way to go. Airing an E down for off-road adventures is fine, but most of the time my truck is on the pavement so I'm looking to maximize my ride quality and wear characteristics with that in mind. Any C rated tire I've looked at also has plenty of load index rating to handle whatever you can reasonably throw in (or on) a 1/2 ton truck.

 

If I were sticking with stock size, Goodyear makes a Duratrac in SL, C, and E.

The SL tire is 47lbs and has a load index of 116.
The C tire is 50lbs and has a load index of 113.
The E tire is 53lbs and has a load index of 123.

The C tire has a lower load rating than the P-rated SL tires at max pressure. Is that a problem? Probably not in the vast majority of cases.

Just depends on your usage. I still think Es will feel more planted when towing and offer better protection off road. Of course that comes at the expense of ride comfort, but I don't notice poor ride comfort at 45 psi with my Duratracs. Are Es necessary for my usage? Probably not. But if I want max ground clearance with an OEM TRD Fox setup, my best option is the skinny 35 aka 285/75R18, and the only tires in that size come in load range E. If Goodyear started offering a C tire in my size, I'd maybe give it a go.

 

The P rated load capacity seems fine for my uses, the stiffness of the LT rated tire was nicer in curves though and for abrasion resistance

 

I’ve had C and E rated, while the C’s felt much lighter on acceleration they had more sidewall roll on highway corners.

 

Mods are gonna think I'm selling these New Wrangler Territories. They are the only 'light duty" aggressive looking AT tires I know of. They are available in 315/70r17 (MT), C load, 35psi max, S speed, 52 lb each.... and 325/65r18 (AT), D load, 50 psi max, T speed, 65 lbs each. Cost ~$300 each. I haven't used them and I don't know if they are any good, but I like the concept.

https://www.tundras.com/threads/wheel-and-tire-weights.121774/#post-3122263

 

You don't say what tire size you have. That makes a big difference.

If you are looking at 315 or 325 width, max psi: C=35psi, D=50 psi, and E=65 psi. Calculators will actually compute something ~25 psi for the weight, but then tell you that at least 35psi is recommended.

If you aren't loaded you can run less in the back than the front, since there is way less weight back there. Mine are at 38f and 32r.

 

Yar these are used on a ton of factory 35/37” tire trucks/suvs now to get the tire size but not a huge weight increase. Same tire the TRX goes 0-60 under 4 secs with. But the weight has to come from somewhere, being 10–15lbs lighter than similar tires means theres less rubber or metal. Thus will they really last offroad who knows, I guess most of these 100k trucks don’t leave pavement so may never find out haha.

 

any one looking for a very similar for "35" tire but in a lower range, Wildpeak at4w has 325/65r18 which is 34.6x13.2 8 ply / D

 

Falken also makes the 35x11.5x18 in a C load. 62 pounds.