Tire Air Pressure

[JB.]

You vehicle will have a sticker probably in the door jam that will tell you what to keep your tires inflated to. This is the how you want inflate for a normal load.

Yep, but it applies to passenger tires and a lot of people switch out to LTs which means door sticker pressure is not enough.

 

[Ross]

Yep, but it applies to passenger tires and a lot of people switch out to LTs which means door sticker pressure is not enough.

Than you have a tire that your vehicle is not designed for. Your tire presure is determined by the weight of the vehicle adn the load it is designed to carry. If you are trying to increase the load capacity of your vehicle this is not the way to do it. There is no good reason to do this. There could issues with handling.

If you want to run a stronger tire (more ply) you still should run the recommended air pressure. The weight of your vehicle didn't change. What are expecting from an LT tire you won’t get from a passenger tire? The rating on the tire is the max rating. You air it up when you are carrying the maximum load for the tire. In the case of an LT that could easily surpass what would be the max carrying ability of a 4Runner.

 

[JB.]

Than you have a tire that your vehicle is not designed for. Your tire presure is determined by the weight of the vehicle adn the load it is designed to carry. If you are trying to increase the load capacity of your vehicle this is not the way to do it. There is no good reason to do this. There could issues with handling.

Well, I can think of one reason (heavy off-roading) but other than that, we're in complete agreement. Fact is, though, it's most often done simply for looks which I'll try not to pass judgement on, but I don't think most people who do that are aware of the tradeoffs.

 

[bigwebb83]

I run 36 - 38psi in my hankooks (p rated) and the contact patch seems fine, handling fine, wet braking fine, ride comfort fine. I wouldn't go much more than that though

 

[Ross]

Well, I can think of one reason (heavy off-roading) but other than that, we're in complete agreement. Fact is, though, it's most often done simply for looks which I'll try not to pass judgement on, but I don't think most people who do that are aware of the tradeoffs.

For heavy off-roading you want an off-road tire. A ten ply tire will be too stiff (for a 4 Runner) to conform to your terrain. There are tires with incredibly strong sidewalls and treads that are designed for off-roading. I ran the old style MTRs C rated in the past and have TrXus MTs (C rated) now. If I wanted an off-road tire for a heavy vehicle I would get E rated . I have 10 ply tires on f250 and the side walls or tread area aren't nearly as tough as the ones on my MTRs or TrXus MTs.

Even though my F250 is a 4wheel drive those 10 ply tires do not offer any beneift off-road, on a lighter vehicle they would actually perform worse. The benefit to the 10 ply tire is I can haul more, that is what they are designed for, not off-roading. There are 10 ply off-road tires (usually stated as E rated) but they would be for trucks heavier than a 4Runner.

 

[Ross]

For a while the Jeep Rubicon came with an E rated MTR. For the most part people didn't like them. They were to stiff on road for comfort and too still to conform to the terrain off-road. There was nothing wrong with the Jeep, nothing wrong with tire, just the mismatch of tire and vehicle.

 

[JB.]

For heavy off-roading you want an off-road tire.

I wasn't suggesting all LTs are designed as off-road tires, but tires designed for heavy off-roading are LTs (or bias-ply).

A ten ply tire will be too stiff (for a 4 Runner) to conform to your terrain.

Stiffness mostly depends on air pressure. The load range is a small factor but, yes, if that tire is being run at proper street pressure and is taken off-road without a reduction, more problems are created than are solved. I air down off-pavement and assume others who use LTs off-pavement do, as well.

 

[Ross]

delete double post

 

[Ross]

I wasn't suggesting all LTs are designed as off-road tires, but tires designed for heavy off-roading are LTs (or bias-ply).



Stiffness mostly depends on air pressure. The load range is a small factor but, yes, if that tire is being run at proper street pressure and is taken off-road without a reduction, more problems are created than are solved. I air down off-pavement and assume others who use LTs off-pavement do, as well.

What rating or ply LT are you talking about. If you get a 10 ply or E rated tire I promise you that it will be a very stiff side wall even aired down (versus a c rated tire). A ten ply tire doesn't actually have a side wall with 10 layers. It is weight rating.

What do you mean heavy off roading? Do you meant off roading with a heavy vehicle like a full ton truck, if so yes a 10 ply would be appropriate.

Bias ply is all together different.

 

[JB.]

What rating or ply LT are you talking about. If you get a 10 ply or E rated tire I promise you that it will be a very stiff side wall even aired down (versus a c rated tire).

I have load range E or 10 ply tires but I would not consider them for a long time due to frequent encounter of the very type of statements in this discussion. I ended up wanting a tire that came only in load E, so it was either forget it or find out for myself. Research gave me enough confidence to try it and I'm glad I did. As a result of all this, I tend to think that most of the reputation for the stiffness of high load tires comes from the fact that they're usually used with higher pressure and that the tire, not the pressure, is blamed.

A ten ply tire doesn't actually have a side wall with 10 layers. It is weight rating.

Yep, plies is an outdated term which is why I use load range (unless plies or ply rating is used in the discussion). If you take a look at a load inflation table, you'll notice the load/pressure numbers for LTs are identical among load ranges, the only difference being that max pressure (and thus load) gets extended up the load range ladder.

What do you mean heavy off roading?

I'm just trying to differentiate between the type of off-pavement use that could be handled by a P-rated A/T and the type of rough treatment where an LT might be called for.

 

[Ross]

I have load range E or 10 ply tires and I was scared away from trying them due to the very type of statements in this discussion. The tire I wanted only came in load E, so it was either forget it or find out for myself. Research gave me enough confidence to try it and I'm glad I did. As a result of all this, I tend to think that most of the reputation for the stiffness of high load tires comes from the fact that they're usually used with higher pressure and that the tire, not the pressure, is blamed.



Yep, plies is an outdated term which is why I use load range (unless plies or ply rating is used in the discussion). If you take a look at a load inflation table, you'll notice the load/pressure numbers for LTs are identical among load ranges, the only difference being that max pressure (and thus load) gets extended up the load range ladder.

I'm just trying to differentiate between the type of off-pavement use that could be handled by a P-rated A/T and the type of rough treatment where an LT might be called for.

If it works for you. I would still prefer a off-road tire with the appropriate weight rating for the vehicle. There are off road tires that are C rated that incredible durable side walls and are still very flexible.