I have the Cooper HT Plus tires on my SUV. It has a temperature rating of "B" - I'm not sure (how can I confirm?) but I believe stock from the factory is 285/50/20 A A.

I drove around in the heat the other day. I noticed the tire pressure (TPMS) went from about 33psi cold to about 36-38psi. Also, when I arrived back home, I touched the tires and they were really hot to the touch (I'll measure them with the IR meter next time - later today).

Reviews of the tire seem generally good - dry, wet and mud performance. However, I'm a little concerned about the tire temperature and pressure.

Is this okay? What do you guys in AZ, NV and other hot desert areas use - strictly A temp rating or B is okay?

We're entering Fall/Winter so I can keep these tires for now, regardless.

But I'll want to prepare for spring/summer if necessary, looking for sales on the recommended tires for my car / usages if suggested. And maybe something with a slightly more aggressive tread.

Tires: less price sensitive - Safety of performance (at speed, emergency maneuvers, dry handling, wet handling, mud/snow handling) - the best balance of all situations. I've read that some people go from 285/50/20 to 275/65/20 or something like that.

This message has been edited. Last edited by: konata88,

Not sure on the temp rating, but if you're looking for replacement recommendations. On the F150 forum, the top 2 I notice are the Michelin Defender LTX & BFGoodrich KO2.

Choice depends on use. The LTX are a highway, light off-road tire. The KO2 being a more off-road tire with good on-road manners.

Michilin LTX MS is pretty much the gold standard for SUV tires but you do pay for it.

The hot and cold airing up temps are always good to know. It isn't complicated but important to know - for every 10 degree increase in temp from the temp the tires were aired up, the psi increases by 1. And it decreases by 1 psi for every 10 degree decrease.

If the airing up ambient is 70 but the expected destination ambient is 30, the psi at the destination will be 4 psi less. Fill up at 32 and in the snowy skiing mountains, they'll actually be 28 and trigger the TPMS.

I had the Michelin LTX M/S on my expedition. I was extremely happy with them in every aspect. They lasted 50k miles in the South Florida heat. I never got ONE NAIL in any of them in all of 50k miles. Even when tread got low, they still performed excellent in all aspects, stopping, rain, etc.

I replaced them with Goodyear Fortitude Wranglers because I got the whole set brand new installed for $675. They're almost as good, but I only have 4k miles on them.

I think the temperature rise is normal on a long drive......

A "B" rating may seem fine since you don't plan to drive over 100mph.

For me, I want an A rating for the improved durability in the event the tire is getting low on air and generating additional heat into the carcass. Preferably as high a speed rating as possible for the same reasons. Difference in ride quality is nominal, and I'll pay a few dollars extra for the safety of me and my family on the road.

I prefer A temperature rating for the desert.

Bruce

Ugh. So, it sounds like B may be okay but given the heat and the speed of general highway traffic, a little headroom may be good, especially for lower psi conditions. Safety first.

So, I guess I'll live with these for now (through the winter) and plan to get a higher speed rated tire (V rated?) as well as A temp rated in the spring.

Anybody in the northwest want these Coopers at that time?

Those aren't the tires on the LX570 you bought to go off pavement are they? They are a nice all-season tire, but your going to want something more aggressive for the trails you posted. The BF Goodrich AT KO2 is a common recommendation. The Cooper A/T3 would also be good.

Tires warm up when you drive and the pressure goes up. I wouldn't worry about a 10% increase from cold tires. That's fairly normal.

Start: ~92 degrees, 34psi

End (drive on highway ~40 minutes): ~140 degrees, 40psi. Hot to touch.

So, yes, pressure did go up about 1 psi per 10 degrees. I guess the question is whether or not the temperature should have gone up by almost 50 degrees (and 6 psi, assuming the TPMS is accurate for this test) or about 15% increase in pressure.

What pressure does Lexus specify on the label on the driver's door post?

Run them a couple of pounds (2-3) above the pressure in the manual. Manufacturers usually specify the minimum safe number to ensure a soft ride. More air equals less distortion and flex and then less fluctuations.
Also, better gas mileage. Just don't overdo it.

Bruce

33 psi.

I set pressure using my last made in USA meiser gauge. TPMS seems to match.

in the scheme of tires 140F is not a concern. I race things and we measure this a lot.
FWIW> the temp rating is in reality a speed rating, so if you drive at legal highway speeds (+20ish ok but not >100) then it is never an issue.

I thought there was a connection between the temperature rating and the tire longevity rating. Tires with thicker tread which will last for more miles tend to run slightly hotter. A nice thin Corvette tire which lasts 20,000 miles has an A rating but you pay for it. I would not be concerned about a B rating for an average driver.

Awesome. Thanks. That's comforting as I don't know what to expect; all I know is that it's different from what I'm used to with my sedans.

Especially for this SUV I'm not planning to do much more than the limit (many areas are 70). Emergency maneuvers are a little scary right now as I'm not used to the roll and other higher center of mass behaviors.

Fill them with N2 and see what happens.

I'm still planning to use the Cooper's on the car now through winter unless it's just not advisable for wet roads and/or snow. Besides, I just don't know what to buy nor do I have the funds to do so, especially with some post sale repairs and maintenance.

However, research continues. I get that LT tires are purpose built for heavier loads, towing, mud/sand/snow. They have stronger sidewalls, deeper treads and support higher pressure. But, especially in the absence of UTQG ratings and testing comparisons for dry, wet, lateral traction, I'm having a hard to trying to figure out what to expect.

I'm used to higher performance summer or all season tires (S02, ExtremeContact DW, and the like). I have a sense of how they can handle speed, dry road, wet road, curves, bumping roads, etc.

But I have no idea how something like BFG K02 or Yoko Geolander or LT tires compare. Do they have high dry and wet traction? Comparable to, say, the Conti ExtremeContact? I'm guessing not. But how much of difference is there in order to get the more robust sidewall, deeper treads, etc?

Can you help me understand generally what to expect between a highly rated LT tire (in terms of dry/wet handling and traction) vs a tire like ExtremeContact or S02?

Or even the Cooper HT Plus tires I have on now? How much street / highway safety in dry/wet/curve/braking performance am I sacrificing in order to get the LT benefits?

A bit of research indicates those are some good tires. Unless you have excessive wear I would not worry about them. I just put cooper AT3 all terrain tires on my truck and love them.

Thanks. Yes, I'm more comfortable with the Cooper tires after having done more research.

But I'm still wondering about getting more capable tires next summer. Perhaps something better suited for beach sand, river banks, lake side and fire roads. Something a little tougher as well as with deep tread. And maybe different size (ie - 285/65/18 instead of the stock 285/50/20).

Still researching if I need/want this. But I'm a little curious about what I'm giving up, if anything. No free lunches and all that. For example, do I have to augment the suspension to accommodate the heavier wheel?

Konata88, I'm in Arizona and have Cooper Discoverer HT tires, temperature range B, on my early Tundra. I no longer live in the "Valley"/Phoenix area but do get down there on occasion in summer. I don't off road, but these tires are sometimes on the freeway in the Phoenix summertime,rain,a good snow or two per Winter where I live now, etc. I have experienced no issues whatsoever with my Cooper, temperature range B, tires.....ymmv