That's something I need to look into. I drove about 2,200 miles in 2020, so.... not much opportunity to wear.
Oversize tires and pressures on- and off-road
- Thread starter greiswig
- Start date
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That's something I need to look into. I drove about 2,200 miles in 2020, so.... not much opportunity to wear.
jlglr4
Full Access Member
I think I’ll try that 4psi rule someday. BFG recommended pressures for my KO2s were higher than for my prior LT tires - I think the BFG recommended pressures were like 48/54 or something like that. But I’m thinking its too much.
I know the E load tires can handle higher pressure and, thus, more load. But I don’t see why, for the same load, you would need any more pressure in an E-rated tire than an LT tire. If anything, it seems like less pressure would be required in the E-rated tire for a given load as the sidewalls are stiffer.
I know the E load tires can handle higher pressure and, thus, more load. But I don’t see why, for the same load, you would need any more pressure in an E-rated tire than an LT tire. If anything, it seems like less pressure would be required in the E-rated tire for a given load as the sidewalls are stiffer.
Part of what's driving me a little nuts about the 4psi rule is that it doesn't seem to account for environmental variables. What's the ambient temperature when measuring pressure cold? How hot is it on the pavement an hour later when you test it hot?
Maybe it doesn't make much of a difference, but I don't know.
What I was hoping for from Cooper was a table that mapped recommended tire pressure for a given weight on that wheel, targeting optimal tire wear characteristics. From what I can tell, none of the tire manufacturers are doing that, unless that is what their tables are trying to say (and not "this is the maximum load that can be carried safely at this pressure").
Off topic: I've used Cooper LT tires on a few different vehicles now, 3 sets in a row, and I've always been pleased with their performance offroad and their wear onroad. One person in this thread or another seemed to be saying they're not as good as BFG, but my experience has been that they're just as good if not better overall in performance, sidewall strength, etc. and probably better in terms of wear. I've also used BFG tires and Yokohamas as part of sponsorships previously, but when I'm buying I've been using Coopers. The Michelin XM-47 is also amazing, but probably wouldn't fit the LR4 without some modifications. ;-)
Maybe it doesn't make much of a difference, but I don't know.
What I was hoping for from Cooper was a table that mapped recommended tire pressure for a given weight on that wheel, targeting optimal tire wear characteristics. From what I can tell, none of the tire manufacturers are doing that, unless that is what their tables are trying to say (and not "this is the maximum load that can be carried safely at this pressure").
Off topic: I've used Cooper LT tires on a few different vehicles now, 3 sets in a row, and I've always been pleased with their performance offroad and their wear onroad. One person in this thread or another seemed to be saying they're not as good as BFG, but my experience has been that they're just as good if not better overall in performance, sidewall strength, etc. and probably better in terms of wear. I've also used BFG tires and Yokohamas as part of sponsorships previously, but when I'm buying I've been using Coopers. The Michelin XM-47 is also amazing, but probably wouldn't fit the LR4 without some modifications. ;-)
PatriotLandyTX
Member
I’m running 275/70 18’s (general X3’s) on my LR3 and find a sweet spot on road about 40psi all around with better mileage than even at 38, and not much change in ride. Then off road (I love rocks) I’m really comfortable at 22. 18 was too low. 25 still too stiff.
Rover 4
Active Member
running 275/55/R20 D range BFG KO2's, so less side wall, 32 rear, 30-31 fronts, seems about right. have even wear, no cupping, etc. i am running with winch in front, and roughly 150lbs in rear, plus a full Baja rack. If you are running an E load range (if they even make it in your size) then more pressure. your Rig is over 6k lbs stock, so i wouldn't run less than 30psi on road.
There are so many frickin’ variables on this topic it makes your head spin!
I’ve got the Cooper S/T Maxx and they’re amazing. Don’t let anyone detract you from your choice.
I’ve noticed the BFG fanboys are a lot like Toyota fanboys. They believe the hype and think they’ve got THE best and can’t understand why anyone would choose differently! Sure, both are fine options, but maybe not a great option and certainly far from the only option.
It sounds like what your running works for you so not trying to change your mind on your pressures, but I’m not sure if I’m interpreting all of what you said correctly. It seems your suggesting lower pressure for shorter sidewalls? As a general rule of thumb I’d recommend the opposite. Also, E rated can handle more pressure (and therefore more load), but don’t require it.
I’ve got the Cooper S/T Maxx and they’re amazing. Don’t let anyone detract you from your choice.
I’ve noticed the BFG fanboys are a lot like Toyota fanboys. They believe the hype and think they’ve got THE best and can’t understand why anyone would choose differently! Sure, both are fine options, but maybe not a great option and certainly far from the only option.
It sounds like what your running works for you so not trying to change your mind on your pressures, but I’m not sure if I’m interpreting all of what you said correctly. It seems your suggesting lower pressure for shorter sidewalls? As a general rule of thumb I’d recommend the opposite. Also, E rated can handle more pressure (and therefore more load), but don’t require it.
I didn't spot that you were using 20" wheels, @Rover 4 . I think the general rule of thumb is to decrease pressure if the overall tire volume is increased. But calculating the volume of a tire precisely isn't easy. Your front and rear pressures being so close together make me wonder right there, but overall I would suspect you're underinflated a bit for ideal wear and MPG.
This weekend, I guessed at the pressures for my tires, which should be larger volume than yours, and came up with taking 5 PSI off the stock pressures, so 32 front, 38 rear. Then I tried that "4 PSI rule" and it looks like according to that rule I need to come up 1 PSI all around for street use.
But, again, I'm pretty skeptical that the 4 PSI method is very accurate. I will probably try the chalk method when I have a chance to see if I can spot how things are really wearing.
This weekend, I guessed at the pressures for my tires, which should be larger volume than yours, and came up with taking 5 PSI off the stock pressures, so 32 front, 38 rear. Then I tried that "4 PSI rule" and it looks like according to that rule I need to come up 1 PSI all around for street use.
But, again, I'm pretty skeptical that the 4 PSI method is very accurate. I will probably try the chalk method when I have a chance to see if I can spot how things are really wearing.
