Hello All,

I have a 2003 Toyota 4runner V8, I upgraded from a P265/70/16 Tire to a LT265/75/16 Bridgestone Revo 2. I emailed the manufacturer and they recommended that I do not exceed 3 percent in overall diameter but gave me this info anyway.

They said from a P265/70/16 to a LT265/70/16 I would have to up it 11 PSI from 32 PSI to 43 PSI. They do not know what would be recommended in a LT265/75/16 (32") but normally when you upsize do you decrease it by 2 PSI? For example, since Bridgestone recommended 43 PSI on the LT265/70/16, should I decrease to 41 PSI for my LT265/75/16?

They also said that they do not know my wheel carrying capacity to make a better recommendation, what does that mean? Do you think 41 PSI is good? I have it at 40PSI right now, 95% onroad driving.

Thanks All

 

This is complicated--but it works out like this

Pressure in the tire is dependant on actual load, Load rating and size of tire. I.e. if you have less weight you can decrease your PSI....etc..

When, I went to your size, I ran at 35 psi--FYI

Toyo tires has a good explanation of this--go to thier website and check it out

 

What were they smoking, we've got some good stuff up here in BC, but i don't think even that could explain their thinking. Running at 41 psi would be like riding on bricks, unless you're carrying 1000 lbs in the back. There is no reason to change tire pressure from a P265/70R16 to a LT265/70R16 or even to a LT265/75R16. I run Nitto TG LT265/75R16 at 32 psi and there're just fine. With my Truxs MTs I run at 26 psi. Granted my 3rd gen is a bit lighter than a 4th gen but not by that much.

Anyway the best way to set the tire pressure correctly is with the chalk test. Get some white chalk and rub all the way across the top of the tire, then drive forwards in a straight line 15 - 20 feet and look at the chalk. If it's worn off in the middle your pressure is too high, if it's worn on the sides it's too low, and ideally it should be worn evenly.

 

I tried to email a different company (Michelin) to compare and this is what they said:
Thank you for your email. We welcome the opportunity to serve you.

"We appreciate your purchase of Michelin tires!

Truong, at 32 psi the P265/70R16 tire will carry 2326 lbs. The replacement
tire, size LT265/75R16, will carry 2470 lbs at 50 psi. We recommend 50psi
cold.

It is our goal to ensure that your issue has been resolved or your question
answered to your satisfaction. If we can assist you further, please respond
to this email or call us at 1-800-847-3435 (toll free) between 8:00AM and
8:00PM Eastern Time Monday through Friday or between 8:30AM and 4:30PM
Eastern Time on Saturday.

Thank you,
Evelyn
Michelin North America
Consumer Care Department"

So 41 PSI from Bridgestone (which makes my revos) and 50 PSI from Michelin. At discount tires they told me to put 40 PSI (I think they put 40 PSI on there for me which is what I am running right now, seems fine but I should check the PSI myself too). I'll try that chalk test out as well.

My driver side placard says 32 PSI cold 2540lbs Front and 2960lbs Rear.

 

you go with the manufactures (Toyotas) rating over what the wheel guys are saying unless your tire size changes alot

I run 28 in my Toyo 35" MT's--They are Load E tires and that work out peachy

 

I bought new Goodyear Wrangler Authority 245/75R16's 3 weeks ago. They are 10ply and the tire recommendations on the sidewall call for 65psi cold. That's what I am running.

 

jazdude... thats way too much... thats recomended for the max load carrying cappacity. i'm running 30 front 28 rear on my 265/75/16 nitto tg... they are ten ply load e rated..

 

I replied to the email from Bridgestone and got this:

Winston,

NO, that’s not how it works. If you are upsizing from a P-Metric to another P-Metric (that is, P265/70R16 to P265/75R16), you would not reduce the recommended cold inflation pressure. P-Metric to P-metric, you can go up but never go down. Again, we do not recommend P265/75R16 since its OD is over +-3.0%.

From P265/70R16 to LT265/70R16 is a different story since you will require higher inflation pressure on LT tires to maintain the same load carrying capacity. If your current recommended cold inflation pressure on P265/70R16 is 32 psi, then you will have to set the new inflation pressure to 43 psi when LT265/70R16 is installed.

Your auto dealership (you may call the Toyota Technical center) is the only one who knows of the vehicle’s wheel carrying capacity. Most SUV’s are fitted with SUV/P-Metric tires that have MAX PRESS of 44 so I would think your current wheels would probably still allow 43 psi. Again, somehow you need to know the true wheel capacity. You don’t want to inflate your tires to 50 or 60 or even 80 psi thinking that because 80 psi is what is stamped on your tires that you can do that.

Rod

I guess I should have 40 PSI just to be safe?

 

40 is safe but keep your eye on them .Some signs to look out for if its overinflated less rubber is contacting the road and you will notice wear on the center of the tire the other way around for under inflated tire will see wear on the outsides of the tire. 40 will be fine but at work we keep it simple 35psi on suv/trucks and 32psi on cars witch also if you look on the door jam of your car there will be a sticker that will tell you the recommended air pressure most common is 32 or 35 we put 35 in most 4runners unless told otherwise also we never put anything lower than 32 and i suggest you do the same

 

I still don't understand why you need to increase pressure going from a P to and LT tire. LT tires have thicker sidewalls, especially when you get into a load range D or E. The load on a tire is supported by both the sidewall and the air inside. Thicker sidewalls can support more load, therefore you need to add less air.

And the pressure stamped on the tire is the pressure required when it's carrying it's maximum load. Example my Truxs MTs are rated for 3000 lbs at 65 psi. Which means if my vehicle weighs 12,000 lbs, 3000 lb per tire x 4 tires, then I would need 65 psi in each tire. My 4Runner weighs 4500 lbs empty so I need a lot less than 65 psi. Even fully loaded I doubt I would ever be over 5500 lbs. That's a bit less than half of 12,000 so half of 65 psi would be OK.

If you really want to get technical about tire pressure you could measure the load on each tire and divide it by the size of the ideal contact patch on the road, that would give you the required pressure per tire.

 

sounds like you know your stuff man also just want to say one more thing if for whatever reason you feel the need to put 60psi in your tires make you have high pressure valve stems if not consider you valve stem gone.

 

I also just picked up a set of LT265/75/16 Bridgestone Revo 2 for my 3rd gen Badlands edt. Costco did some math and told me to stick with a 50psi nitrogen fill. Drove around city and highway all day today and it seems like way too much, ( can feel smaller stuff that I can't even see on road ) Did you find a sweet spot for the psi for comfort and mpg.

Also if anyone is thinking of pulling the trigger on these I will say they make the truck steer like a sports car, traction wet and dry is unreal.



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I to have contacted brigestone and sent the guy a picture of my drivers side door jam as per his request. I'm currently using 44 psi and the tire looks slightly under inflated looking at the side wall. The truck also feels a bit more mushy and unstable in corners. When the tire was at 50 and even 47 psi the tires outside tread mud blocks had about a inch on the inside and the outside of the tread that was not even really touching the ground. ( when I drive into a underground I can see that there is no dust on those parts of tires)

I'll post the response I get from brigestone.
If I can't get it sorted I may take them back and get the bf goodrich at ko in a C or D rating

 

chalk test the tires to find the best psi with that tire for your rig.

 

I hear you, it's kinda the same as driving in a dusty underground though. I can see even though it looks and feels under inflated it's still not driving on the whole tire. So either that is the way the these tires are (doubt it) or the e rating in this tire is just to much for the truck.

 

I think an 'E' rated tire is a bit much for a 3rd gen 4runner.