If the tire is B rated or above, you won't have any problems. (I doubt you would have a problem with a C rated tire)
I'm in AZ too - right in the heat filled hellhole known as The Valley of The Sun. I drive my 1st gen Tundra, loaded with crap to go camping, at freeway speeds (80+ MPH) in 118+ degree temps on B rated Cooper ATPs.

If it makes you feel better, it's your money not mine. I think you worry too much about things that you will never have to worry about unless you are racing your SUV on a track.
Who the hell puts a tire rated for 149 MPH (V rating) on an SUV?? If you want to throw money away, my email is in my profile. I'll even take personal checks.

A LT tire of load range C (P tires are B), sometimes called a 6-ply rating, would have thicker sidewalls and therefore a little more puncture resistance against sharp gravel, stones and such. The rest of the time it will ride a little firmer, but not enough to be stiff.

konata88, spend some time on the Tire Rack website. They do a nice job in explaining tire ratings and also show what OEM tires and specs are. They include their test results for some tires and reviews by users. It is a very good source for info.

 
If you are choosing between P and LT tires, it can be somewhat confusing. P tires are required to have the UTQG code, which will give the manufacturer's ratings for speed, temp, treadwear, and traction. LT tires are exempt from having the UTQG code. They will generally show a Load Rating, indicated by a letter that does not correspond in any way to the letters used in the UTQG speed ratings. The LT load rating will correspond the number of plies, and the maximum pressure. For example, a E rated LT tire has 10 plies, and a max pressure of 80psi. Tire Rack has good pages explaining all of this.
 

Sorry guys, I caused some confusion. Subsequent to the original post, I'm now okay with the Cooper tires, at least for street / highway use.

However, I'm wondering if I should get something a little more robust like LT tires that may be more durable off pavement if I hit a rock the wrong way or something, or deeper tread for soft sandy beaches / muddy riversides.

So, I'm looking into LT tires with deeper tread, more durability and an ability to air down a bit.

My question, never having owned a truck/SUV or LT tires, is what I might expect in terms of dry/wet traction and curve handling with LT vs the high performance (S02/S03/ExtremeContact) type of passenger tires I'm used to.

I can find qualitative info on mud handling and load handling. But nothing on explicit dry/wet/curve performance like I can for passenger tires.

That being said, it may be irrelevant. I'm trending toward 18" for LT and keeping the 20" for street. I was hoping to have the 18" be good for street and everything else. But doesn't sound like it would be ideal.


On the side: I bought what I think is a non-USA made Meiser accugage.

Same tire, it's reading different from my USA Meiser. I would normally suspect that my older USA made one would be due for calibration. But, the TPMS sensors are matching my USA Meiser. Which suggests my new gauge is reading high by 5psi (33psi vs 38psi).

Not sure if I should return and get something different or just remember to apply a 6psi offset each time.....

The LT's will have deeper tread and may help in off road applications. The main difference is weight carrying capacity. That is designated by Load Range. E for example is 10 ply rated. Not actually 10 plies. And those weight carrying capacities are uniform across brands. Size X Goodyear and size X Cooper will have the same weight carrying capacity if they are the same load range (but not necessarily the same physical dimensions, go figure). It has been my experience in over 40 years in the business that the LT will NOT help you in resisting punctures other than the increased tread depth could help if you run over a short nail.

You are over thinking your tires and you don't seem like a guy thats going to switch out wheels everytime you think you might go off pavement. Get a good set of all terrain tires and call it a day. Plenty of choices in the 285/55r20 which is slighty (1/2 inch) taller and slightly narrower (3/4") than what you have. Even if you make it your daily driver, a good set of all terrain tires will serve you well.

The Goodforayear Wrangler All-Terrain Adventure w/Kevlar I have on my truck have enough wet traction that I don't run the truck in 4wd even in a down pour because they chatter instead of slipping smoothly and I don't want to put undue stress on the drive train. So did the Michelins I had before these. They handle fine and take curves much faster than I should in a pickup. For example, I was running KY-90 near Cumberland Falls at speeds that my wife really didn't approve of. Really, look it up on Google Maps. There's two 220 degree back to back turns that I thought my wife was kill me on each time we drove through them.

Yes. You're right. I have a tendency to over design. I hate when things break easily / unexpectedly which may explain part of my strong aversion to cheap crap from PRC. Especially when high dollar value items and/or safety is involved. And doubly so when my wife's safety is involved.

And I'm probably way overcompensating for my lack of knowledge and experience here.

I may not do anything. At this point, I'm still just trying to understand what the difference is between LT and P tires in terms of street and off pavement capabilities (dry traction, wet traction, braking distance, curve g-force, terrain handling, etc) and what the functional pros/cons of best of breed is. That way I can make an informed decision of what to use on street and off pavement (hopefully the same tire).

It's just very confusing and difficult at this point to make those distinctions. I'll probably resort to first hand experience.

quote:

Originally posted by Krazeehorse:
The LT's will have deeper tread and may help in off road applications. The main difference is weight carrying capacity. That is designated by Load Range. E for example is 10 ply rated. Not actually 10 plies. And those weight carrying capacities are uniform across brands. Size X Goodyear and size X Cooper will have the same weight carrying capacity if they are the same load range (but not necessarily the same physical dimensions, go figure). It has been my experience in over 40 years in the business that the LT will NOT help you in resisting punctures other than the increased tread depth could help if you run over a short nail.

My 2008 Expedition came with Continental P rated tires new. It would pick up a nail in 1 tire every 5,000 miles like clockwork. I switched to Michelin LTX MS's and in 50,000 miles never once got a nail in a tire....