in shopping tires, there is a big disparity in loads and corresponding psi's. why are some (toyo for instance) tires rated differently?

Im comparing 35/17's to 295/17s (which I currently have) and the corresponding weight to psi is approx 3600 at 65 to 3900 at 80.

for those with more experience here, is 80 psi really critical for towing loads of 10K pound trailers or is 3600 at 65 psi sufficient for once every couple of months towing at the 10K weight?

I would expect that non-towing tire psi's would be close to the same?

 

lower psi the sidewalls tend to roll

 

Tires in sizes like 31x10.5,33x12.5x35x12.5,etc are called floatation sizes. Tires in sizes like 265/70/17,285/70/17,315/70/17 are called metric.

The floatation sizes will usually have a lower weight rating for their size.

Take Toyos M/T for example. A 35x12.50x17 will have a lower weight rating than a 315/70/17. Both tires are basically the same size.

As far as a D rated (65psi) tire and an E rated (80psi),I've done the lighter D rated tires on a HD truck and won't do it again. The Ds don't handle or wear as well as the Es will.

 

I put D rated 285 Cooper ATR's on my truck and had no problems for 2 years, then last year I had 2 flats while going about 65 mph towing the trailer, both times when I took the tire in to get repaired I was told it's sidewalls were shot and the tire needed to be replaced.

Now I'm putting AT 35's on and want to make sure they're E rated which are hard to find, you have a choice of Toyo MT's or the ones I found, the Interco Vortracs:
http://www.intercotire.com/tires.php?id=17&g=1

Ive only found a couple people who have them, they're fairly new on the market.

I've had my truck over the scales empty, the front axle was 4500 pounds, when loded it wouldn't take much to get that over 6000 pounds which is what my Coopers are rated for.

I think if you don't tow or haul a lotta weight you'd be okay with D's but I just feel better going to the 35" E's, we'll see how they work for me, should have them on in 2 weeks.

Toyo and Nitto make some 305 and 295's E rated tires which are 34" but I wanted to stick to a 35 this time.


BTW, here's the thread I started you may be interested in along the same lines as your question:
https://www.dieseltruckresource.com/...d.php?t=233258

 

Now you've thrown me off. I was about to put the Mich 285-75-17 D ltx-at2 on my truck that I tow about 8k total several times a year. Wanted something just a little bigger than stock and a little more dirt ready . But now with the tire sidewall thing I am not sure. BFG makes a 305-65-17 E in their KO's but not sure about noise and wear on them. Getting boared with the 265's E highway. Nice,smooth, quiet, and boreing.

 

http://toyotires.com/tire/pattern/open-country-at

I just put on the 285/75R17 they carry 3970lbs at 80 psi and are 33.8 inches tall.

I had them filled to 60 psi as I'm running empty now I have 150 miles on them and they haven't done anything stupid so far so good.

They are quiet too.

 

The Toyo 295 MT has the same weight and pressure rating as well

 

Ive been running the 295's myself, and have been pleased, but wanted to step up to 35's like you Fisherguy.

the 35 toyos are rated for like 3600 at 65 psi, not the 80. So Im trying to gauge wether they will be well suited for my needs, or if I really need the 80 psi of the 295's

 

Yeah, it kinda edit me off there's so many 35" E rated tires for 18" wheels but so few for 17's.
I think the narrower the tire the more air is required to take the same weight, that's why the 295's need 80 and the 315's need less air pressure.

There was some good posts by knowledgeable people in the link I posted, for a while I was going to try the Pro Comp XT AT's but then I found the Vortracs, I just hope thet last, they start out with quite a bit less trad depth than the XT AT's.