Optimal tire pressures for daily drive

There's what the door tells you and then there's some trial and error to optimize ride comfort/fuel economy.

I'm coming from a Tacoma so the 4runner is already smoother so I don't care as much about how soft/comfortable the ride is, I want to maximize fuel economy for my daily commute to work. What's the best tire pressure for that? I currently have 35 psi from the factory and I'm hitting the window sticker numbers right on the head (averaging 19mpgs) with a 20% city/80% hwy commute with very light accelerating and babying it with less than 100 miles on the odometer so far. If I increase tire pressure more, obviously the ride will be stiffer, but will I see any drastic improvements in fuel economy or is 35 psi the right pressure for that?

For reference, on my Tacoma, the door said 30 psi, but I would do 33 psi and I would see a 1-2 mpg increase as compared to 29-30 psi...

 

You could go up a couple pounds and see what happens.

But over-inflated tires get better gas mileage because you have a smaller contact patch and less friction. That smaller contact patch will also negatively impact braking and handling. I'd hate to be upside-down in a ditch thinking "but at least I hit 19.5mpg..."

 

Stock tires? Probably best to stick to what’s on the manufacture recommendations. I run 40 psi in mine but have 10 ply tires.

 

I run mine at 38. I find it's a good compromise between ride and MPG. I'm keeping an eye on the treadwear and it's been very even.

Your experience and needs may vary.

 

I usually run around 35 psi.
pushed it to 38 last few weeks. noticed a slight amount of noise from the front end at low speed (like around 1-2 mph, parking lot type stuff). raised front end and could see or feel anything loose or rattling. dropped pressures back down to 32 and don't notice any noise. I do tend to be paranoid about vehicle sounds (years as a chevy driver)....and I wouldn't think that that little psi difference would have any effect on those kind of noises. gonna keep an eye on things.

 

You could start with a chalk test to find the ideal PSI and then slowly bump it up to find your best compromise between mileage and ride quality. Tires are really expensive, and ruining a set to save 1 MPG doesn't make much sense.

 

The chalk test is what I used. 35 lbs seems to be the best

 

Like JET4 and Deux said, do the chalk test. Should be done on every set of tires you get to determine the optimum psi for that specific vehicle and tire combo. I then write that psi on the door frame in silver sharpie so i dont forget and have to do the chalk test again.

https://m.youtube.com/watch?v=FabWgDAulGg

 

I have always run at the recommended 32 on all three of our Runners and have experienced nice even tread wear.
Tires are too expensive to ruin the tread prematurely.

 

I stick to 35. Have in all my cars for years

 

I've been 2-3 lbs over spec for 20 years. It actually gets better "wet" traction per many tests, which is why I do it. The gas savings are irrelevant to me.

 

How's the noise on 40? I have 10-ply also and keep it around 34-35.

 

35psi in my 285/70/17 WildPeak ATW3 P's.

 

I checked out that chalk test video. I see it as a fail. The chalk pattern on the rear never matched the pattern on the front. He called the pressure good while the tire was still riding high on the center of the tread. Maybe he should have dropped the pressure in the rear a little more. Or maybe the load rating of his tires is too high for the unladened bed of his truck, preventing him from ever getting a good contact patch with an empty bed. Or maybe the concept of the chalk test is invalid. But one way or another something seemed hinky with his test.

 

Agreed! The chalk test is probably nice for figuring out treadwear, but won't tell you the proper pressure for load carrying. At the very least, the rears and fronts should be tested separately, since the weight on each axle is different.

This is a good place to figure out ideal pressure for tires of a different size and/or load range:

 

Yeah, the chalk test sounds good in theory but how many PSI over and under does it take to make a real visual difference? +/- 5 PSI? +/- 10 PSI? Has anyone done this and can report?

I inflate my OEM size tires to 34-35 PSI. I did the chalk test and it looked good so that’s what I use.

 

Very good link, thanks James!

 

Interesting. I input stock tire values into the pressure calculator, along with values for 275/70R17, and then hit the calculate button. For the C-rated version of the 275 it returned a recommended pressure of 41 p.s.i.. For the E-rated version it also returned 41 p.s.i.. I would have predicted that the stiffer carcass of the 10-ply E-rated tire would have called for less pressure.

 

my 2016 runner 38psi front 35 psi rear. the tires I rotate around 7500miles and all the tire look the same wear treads area all the same wear. more weight on the front engine location ..my MPG in the warmer temps around 20-21 MPG ...
on the jan2021 the USA drops all the oil/nat gas contracts and pipe lines fed goverment ...

 

Not quite understanding the correlation between tire preasures and gas/oil contracts?

 

That makes two of us. I don't get it, either.

Anyway, I have 275's, load C, and I run 'em at 40 psi. Get 18.5 mpg with full skids, sliders, 1/2 bumper and winch. 2" lift, too.

 

many increase the tire pressures then increase the gas MPG NOW!!!! 50PSI to the MAX !!!!!!
now the gas gallon cost doubles...LOL....dump the 4runners and go to work with a motorcycle or a bike ....

 

Don’t notice too much of a difference, but I’d have to say it’s probably slightly louder when the psi is lower than 40 like on cold mornings. On mud terrain tires it would maybe make more of a difference, but the all terrains I have aren’t very noisy.

 

I can't explain, but it seems that all LT tires in a given size will require the same pressure. I think the pressure is based on a tire's size, and the load it must bear. Even treadwear might not be a concern.

The difference between SL and LT is also a bit mysterious, as I can't seem to find a good answer on how they determine the exact difference in pressure required. I just follow the calculator and have had good results. OTOH, I ran LT's in stock size at 35, as opposed to the recommended 44, and wear was fine.

 

Interesting!

 

Didnt go back and read everything but also adding weight like bumpers, winch, sliders, skids, etc. can call a need for tire pressure change. And like James says all tires have different loads on them. Chalk all 4.

I’ll stick with the chalk test that gives you an actual visual of the tire tread to pavement contact.

 

Size, age, ply, category, ambient temperature, speed rating all dictate optimum tire psi. To say I run X psi means nothing when dealing with all of the variable's. The door sticker is ONLY for OEM tires and replacements that are the same tire. Funny reading on the Jeep Forums with guys running 38psi (cuz that what the door says) and cant figure out why their rig tracks all voer the road, is loud and bumps are now terrible. Ask the installer what their opinion is. If what you buy is not what came as OEM and they tell you "whatever the door says"... ignore them all together.

 

So I will soon (this year?? ) be getting my 2022 T4R, and am curious how running different tire pressure will affect the TPMS. My 07 FJ doesn't have TPMS so no problem with whatever pressure I run (which happens to be 50 PSI in my Hankook Dynapro MT E rated 285's). I'm just thinking the TPMS light would drive me nuts. So is this just a case of sticking some electrical tape over the light, ignoring it, or is there a way to reprogram the system to reflect the pressure you want it to recognise as your default?

 

I'm pretty sure you can change the default tire pressure in the system

 

I don't know about reprogramming the system. But, 50 PSI is crazy high! The "proper" pressure for LT285/70/17's on a 5th gen 4Runner is 38, although some probably run a bit less. I'd imagine an FJC would be similar.