Hey guys..

So I have a question about the various load rating of tires. My truck needs new tires and I have come down to two choices

P275/60/20 D class load rating from Nitto in their Terra Grappler A/T
or
LT275/65/20.. E class load rating in a Nitto Terra Grappler A/T

I know the differences in size and would prefer the LT275/65..

I'd like to get the extra inch taller tire.. figure it'll look better and it can't hurt to have a higher load rating. My question is in regards to the max PSI listed on nitto's site. The LT tires with the E load rating say a max PSI of 80 psi... holy hell right? Where the smaller tire is only a 35 PSI..

I have talked to various tire shops and they said the larger tire would fit and didn't even mention any downsides whatsoever. A friend of mine who is a mechanic mentioned to me about the PSI thing which I had never noticed.

So if I get the LT tires must I keep them inflated to 80 psi or somewhere close to that.. would running them at 35 psi like most other tires cause wear issues? also would it hurt my TPMS sensors if I have the tire inflated to such a high level. I figure the sensors wouldn't be worth a **** anyway if I have to have the tires up at such a high pressure because the sensors are programmed to turn on the warning light at around 28 psi.. which would be SUPER low if I wanted to keep them near 80..

I've tried google searching and haven't been able to find anything about this.. My guess is that most people don't even notice this and run their E tires at a regular 35ish psi? I need these tires ASAP had one blow out on the highway and either I run my spare for however long or get new tires...

 

The max psi on tires is just that...the maximum psi...not the optimum at all times.

I don't know about your tpms...I wouldn't think it would hurt them, and you can likely reprogram them if they do turn on at a benchmark number.

 

Look HERE for size fitment. It's about tire size not load ratings.

As for PSI, you should go by Dodge's specs in the door jamb for any and all tires, not the tire specs that are put on the tire as those are just max ratings.

 

^ Agreed. That 80 psi is for something like 3042 lbs per tire. If you had your truck loaded to 12,000 daily, then yes, run 80lbs. But the pressure on the doors is what you want to go with. If you notice abnormal wear, change it up. I run my load range e tires at 40 in front, and 55 in back. Thats not what my doorjamb says, but I load the truck up pretty often, and just maybe my mpg has gone up .0000001mpg with the extra air.

 

Yea I honestly had no clue about load rating and such..

My truck sees literally no use as a truck on the road lol... I think I've had something in the bed... maybe twice..

Dog, that thread I've read before and it's definitely helpful. I'm not worried about sizing I know what's going to fit the truck or not.

From what I've been reading I'm thinking that an E class tire is not the best decision for me. The ride quality in such a light truck being a RCSB and the fact that I never tow/haul or put stuff in the bed.

So.. I'm not really sure what I should do exactly. I like the nitto's but I really don't think an E load rating would be the best for a truck like mine..

My old man just got a set of cooper Discoverer A/T3's and they are pretty damn awesome looking. in the LT sizes they only have an E class 275/65/20.. or in P they have the 275/60/20. I'm not worried about the increased cost of the E class tires but I'd be a bit ticked off if I spent almost 400+ dollars more for the LT tires with an E class load rating and they make my truck ride like a brick and drive worse than before.

From what I have read I might prefer a D class load rating or C class but nobody seems to have them in the right sizes for a 20" rim. Info online seems to show that the LT tires have a stiffer sidewall and may improve cornering and improve any slouchy feel. But I'm not really noticing that with the ****ty wrangler HP's that came stock.

I've driven 40k on the stock goodyears with little problems and those are a p275/60/20. So maybe just stick with what the engineers thought best.. keep a stock size and type of tire just go with an all-terrain tire that isn't quite as ****ty as the wrangler HP..

thoughts? anyone change from a P to LT tire and notice a difference?

 

Get yourself the Cooper LTZ's. The load rating is XL as they put it. Its a 119 class Ibelieve?? which is around 2300lbs. Slightly stiffer than the "car" tires that come stock(suckyears) but it's barely noticeable and the slightly added load rating gives better puncture resistance. I think the ride is fine, but an E-load would def be too much!

Ohh, and they are reasonably priced. Up from last year, but stillunder $200 a tire shipped


Or get the class D Nitto's

 

I gotta disagree with the consensus in this thread. I've had this discussion with guys "in the know". A good buddy of mine owns two tire and auto repair shops in south Georgia and we've had the PSI on the tire vs. the PSI on the door jam discussion.

The information on the side of the door is for the tire size and load rating that it says on the door. Chrysler, like any other manufacturer, recommends only replacing those tires with an equal size and load rated tire. When using a similar size and load range tire, sure, the information on the door jam is prudent, but not when changing variables! Not supporting modifications from stock is normal with any manufacturer and is the reason you cannot change the min/max PSI settings on the overhead for the TPMS. But just like you can't recalibrate your speedo for different size tires because manufacturers simply don't support mods, you can with the STARSCAN TOOL, and same with the TPMS range settings.

You run you some 80 PSI, E-Load tires at 35 PSI and see how many miles you get out of them. Yeah, the ride will be more tolerable because an E tire is a VERY stiff tire, but you won't get more than 50% the life out of them as you should. Let's talk gas mileage, you compare your MPGs with an E tire at 35 PSI and then on a couple of tank fulls up around 60-65 PSI.

For the optimum performance of a tire, in balancing fuel economy, wear and performance in normal driving conditions a tire should be run at about 80% of max PSI.

YOU SHOULD MATCH YOUR TIRE TO YOUR INTENDED USE! Don't just consider the tread pattern for your driving conditions, but look at load range as well.

If you haul and tow often and it tends to be heavy weight, then yeah, an E tire should seriously be considered. But if you don't, you won't have the right tire and unlike with a heavy load which will smooth an E tire right out, driving one around unladen, at proper PSI will be rather harsh.

If the truck is a daily driver and you carry more groceries than anything else, the you should be looking more at a "C", "B" or even a "P" (passenger car tire), although it's commonly done, I'd hesitate to run a "P" or even a "B" tire on a 4x4 QC, but they can be the best combo on a RCSB.

It's the "C" load range tire that Chrysler (and most manufacturers recommend for a 1500 series half ton truck). Most C tires on the market have a max PSI rating of around 44 PSI. Running this tire at 35 PSI as the door sticker indicates is what? How about roughly 80% of the max. Hmmm... Seems someone brought that number up before?

I run a "D" tire myself, in a 35x12.5x17. Good compromise for on-pavement, mild off-roading, hunting/fishing and the occasional hauling of up to about 8000# that I'll do a couple times a year. If I pulled the tractor/rough cut and trailer that weigh 7700# more than three or four times a year or more then the 25 miles or so I pull it, I'da thought more seriously about an "E" tire, but for my general uses, the "D" is perfect.

Been running these tires for a little over 32k now. Max. PSI on them is 50 (a D will usually have a max of between 50 - 65 depending on brand) and run them dead on 40 PSI, unless I air down a bit for off pavement. Here's a pic of tire wear I took about 1100 miles ago:





You run you some "E" tires at 35 PSI and send me a pic of them at 30K miles, if they're still on the truck.



In all honesty, Ben, I'd be looking into some 17" wheels. Unless you went with "bling" wheels you could buy wheels AND tires in 17", not spend much (if anything) more than just 20" tires and bring in a plethora more choices in tires and load ranges. Plus, with the 4.7 V8 you'll probably see an increase in fuel economy as well. Plus you'll save a boatload of cash the next time you need tires...

 

Hammer, I've had conversations too and not knocking your buddy, but....Just because he owns a tire shop doesn't necessarily mean he's an expert tire guy. It does means he's a good business associate! The Owner of the furniture store I'm currently working at only knows so much about furniture...which aint much and he's very active in his business.
On the same token, I owned a detail shop for several years and there are still guys out there that know way more than me. About detailing??? YEP, more there to know than the average guy thinks! I'm just saying....

I've NEVER put an E-load range tire on any of my trucks as they were 1500's. But I will say that if you put the same amount of air pressure in 1500 as a 2500, the tire will wear differently. Plain and simple. 80% of max rating for a 1500 is too much with an E-load and will not allow the sidewalls to sag as they need to.
Problem here is comparing apples-oranges and there isn't any reason to put an E-load on a 1500 regardless of the application. Guys do, but that's their call and it's unnecessary. The tires are heavier, they don't absorb the impact they should and it beats the crap out of your suspension and front end components(talking about for 1500's)
I have always ran 35psi in all my cars and trucks. Never had any funky weear problems. 35psi within a load range or 2 is perfectly fine.
If you go putting Tractor Trailer rims/tires on your truck(I've seen that before) you wouldn't go putting 100psi in them as they hit a certain point much sooner than 80psi where they will wear perfectly because the lighter weight of the truck doesn't crush the sidewall. As a matter of fact, I'm pretty sure you could mount a no air tractor tire on a 1500 and it won't even crush....lol

The whole problem with tires is that for starters....Most people don't understand how air pressure inside a tire works and why adding weight doesn't effect the pressure just the sidewall, also that most tires when adding air hit a point where the tread is perfectly flat(no wieght on them) and more times than not, it's around the same psi because the load range tires account for Extra weight which you wouldn't have. Sure the stiffer sidewall flex's different, but you need to think of the lighter wight your putting on top of them. The main thing that added load ranges do is allow for more sidewall strength so they don't buckle or roll under heavy weights. Putting 80% of air in an E tire on a 1500 isn't going to allow the sidewall to "crush" enough to make the tread pattern touch the ground.

And it's time to get new lug nuts and replace those center caps Hammer, or atleast use some Neverdull and clean them up ;-)

 

Hmmmmmmmm. My Uniroyal HD/Ts are at about 3/16" now, and they have been on the back for about 15,000 miles, and the front for about 15,000. Tread depth was originally 9/16". They have been inflated to about 40 psi their whole life. And I can almost guarantee that at 4700lbs with just me, tools, and gas, my 3/4 ton is lighter than almost all of your 1/2 tons.

So the question is . . . is losing 6/16" over 30,000 miles good or bad? I have only gone through 2 tires on the truck since I've owned it, so I really can't comment how it is vs other tires on the same truck. I do know they have worn perfectly straight and level, and I do know that compared to what hammer's tires look like at 30k, they look like crap.

 

6/16"? You mean 6/32nds? Or are you using a ruler?...lol

Most truck tires in E load range vary from 12/32nds -18/32nds and are rated for 40-60kmi and that';s running them down to 2/32nds(by manufacturer specs) So you essentially get 10-16/32nds of wear at best.
Take the low side of 10/32nds and divide that by the high side of 60kmi and that's 6kmi per 1/32nds of tread at best. The low side would be 16/32nds of wear at 40kmi.(2.5kmi per 1/32nd)
I'd say your wear is normal, which is 3.75kmi per 1/32nd of tread wear
Just for full complete comparisons sake...You are right at 40-45kmi of wear for the life of your tires.

Tires wear different on different pavement and in different temps. Drive a tire in Canada on cold smooth ashpalt and it'll wear a looooong time. Same tire on cold rough pavement will wear much faster.