MrEMan
New member
How did they affect your MPG?
They lowered it, but I'm afraid I can't tell you by how much ... over the years my MPG has gradually lowered due to a variety of changes. E rated tires are just one of the changes.
How did they affect your MPG?
I'm running E, but only because it's the only rating available for the tire and size I wanted
Ride is firmer but not terrible. My only issue with it is how little the footprint changes when aired down. We'll see how much that changes as they break in and that will decide if I choose a lower-rated sidewall for my next tire
My D-load KO2s never changed (not 4R).
At what psi does traction improve? 20?
My D-load KO2s never changed (not 4R).
At what psi does traction improve? 20?
Traction is improved with any drop, 10-20 PSI is usually where I target depending on what I'm doing. The Wildpeak AT3ws (also technically E-rated) would have a nice bulge at 10 psi, the Cooper STT Pro's show minimal sidewall bulge at the same pressure. Rolling over rocks/bumps you can see that it is aired down; it's just not as dramatic an effect.
I'm not sure on the traction part, where the point of diminishing returns is. But I can tell you from 20 to 15 there is a difference in ride smoothness driving over bumps and rocks.
The tradeoff is a more exposed/lower sidewall that could be cut up or gashed more by rocks so use a sturdy tire.
Let's leave the soft stuff aside, that requires low pressures anyway.
The soft stuff is about the only time you need traction from your tires. Anything else, anything in Moab, you can do with any set of tires, all the rocks are well rounded and like sandpaper, tons of grip.
...
Are you thinking that P-rated grips around rocks better the D/E for a given pressure, that's what gives it better traction?
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Fun discussion! I agree with your bottom line about Utah but the devil is in the detail.
Mud is mud. Different story, I can totally see an MT and E-load there. I can do reasonable mud when needed but try to avoid mud. Not a fan.
On slickrock any tire will do if you have a quality 4x4 system--easy to say from a 4Runner perspective!--and enough contact patch. If either one does not suffice, airing down is the only way.
Yes, I am thinking that a P-metric will always provide better traction than an LT-D/E at the same pressure because it is softer and thus offers greater contact patch. The price you pay is more sidewall exposure on typically weaker sidewalls. And then also pinch flats. And then they blame the tire. This is why people should not air down unnecessarily on P-metric tires. I would stay 25 and up. Soft sand is different.
I have 2,800 unpaved miles in Southern Utah, more than anywhere else, with no punctures. Most were on P-metric tires. 550 of them were on the 4R and the Wildpeaks including to the furthest point of the Maze. We do not do "hardcore" stuff but we go out whenever we can.
Central Arizona is much harsher on the tires and the 4x4 systems alike. There are a few great dirt roads, but beyond that the rocks are sharp and nasty and they do not provide traction like sandstone does. They do make for serious traction challenges. The sand is coarse and is often mixed with small rocks making for a constant beating of the kind that rarely happens in Utah. It does not seem like much but if it is uphill, you need something more than just 4x4 with low range and open diffs (whether it be traction control, locker, or low tire pressures). And there are more types of AZ terrain where traction is an issue.
Here is where I see the LT-D/E advantage:
--You drive terrain so hard, you need to drive on the sidewalls. That means body damage risk is very real, so not my fare.
--You drive rocks so steep and jumbled, you need the strongest of tires and lowest of pressures and beadlock wheels. That's the sport of rock crawling so not applicable here.
--You need to drive in soft sand a lot. This is where I totally don't see the P metric advantage. You have to air down anyway and you have to expose your sidewalls. Better go for LT-C minimum, LT-D/E better for remote areas.
--You have a built rig, travel really heavy, and or tow a lot, especially offroad. So if you are Jason, I don't see the P metric advantage at all.
--Obviously, if you have no good options in your tire size in less than LT-D.
So, yes, I can see how for some forum members the E/D advantage is very real.
Just curious what tire size you run? Something around 33" might be harsher than a comparable 35" tire. I don't see much discussion about this and it may cause some discrepancy, not sure.
As far as contact patch, physics says it's only a function of vehicle weight and tire pressure, nothing to do with P vs E though in the real world maybe it is different, its not like anybody actually measures it. Then there's the argument when airing down you are only really increasing the patch area front to back and does that actually gain you anything or does it hurt you having less total force/sq in. Probably depends on the terrain.
Anyway, that's about the extent of my knowledge on the subject. More questions than answers... A bit off-topic too.