What psi should i run?

What Im gathering here from reading all the info (which is absolutely effing awesome) is that if I have a stock 14 DBL Cab with the BFG's that toyota installs should be 29/32 according to the door. I checked mine today with 600 miles on the truck and i was at about 40 all around on a relatively cold tire. Do you guys recommend going to the 29/32 pressures, driving around and adjusting from there? I do about 50/50 between highway and city...

Thanks for the help!

 

40 is way too high. Especially if it was cold, with heat from the friction and from daytime your pressures gonna be even higher than that. Take em down right away. From what I hear (I forget why) but dealers tend to keep their tires up a bit higher than normal for the cars on the lot. But if they installed newer tires since you bought the truck, kinda odd they would put them that high. Max pressure is probably 35 on those! I just fail to understand why people do this at tire shops and have no clue about proper tire pressures. Or fail to read the Damn tire to see what max is and make a judgement off that alone on pressure. Really surprised Toyota put them at 40! Wtf! That's why I ALWAYS check my tire pressure if I have any shop service my tires. And if it's ridiculously high I make it a point to go back in and explain what happened.

 

Funny that your bring up the subject of tire pressure and dealerships....

Just last week the low tire pressure sensor in our Optima (in my sig pic below) came on. I keep a good eye on tire pressure in all of my vehicles (probably the most important factor to MPG and safety that 99% of drivers don't bother ever checking) so I know that they're all within 1-2psi of target pressure & each other unless there's an issue. The wife (also in the sig pic below) told me the light was on so I checked all the tires immediately and, as expected, 34.5-35psi all the way around. Evened them all to exactly 35psi resting temp at a moderate ambient air temp and then went to the spare. It was 52psi when the tire calls for 60psi so I was confident this was the problem and put the extra 8psi in it. The next day my wife drove to work and the light still hadn't gone off so she called the dealership to schedule a service appointment for a potentially bad sensor. The service manager (yes, manager) told her that tire pressure can vary greatly and she should just put 39psi in all of her tires and she'll be fine. 39psi. Mind you we live in Colorado and the day she called the high temp was an unseasonably cold 55 degrees. This means that if she fills them to 39 psi cold during a 55deg day her likelihood of a blowout at highway speeds when it's nearly 100deg increases dramatically. This is very dangerous advice they're volunteering to customers who call to schedule appointments to check a TPMS. I can't believe this is what the service manager of all people is telling people who call. Fortunately I know better but most who call would not. That very day the light reset itself when she left for lunch so fortunately we weren't forced to take the car into that dealership. Just a little side story to showcase how trustworthy a dealership should be when it comes to matters such as tire pressure.

 

After reading this thread i went out and checked the tires of my new 14 DCSB TRD OR. Tires were cold. You were right they were all set at 40 psi. Sticker says front 29, Rear 32. I set the front at 32 rear at 34. We will see how they ride and wear. What do you all air down to while out wheeling?

 

Just got a recall on my 2012 txPro that is changing the air pressure in my tires from 29/32 to 42 all the way around!! Sent me a new door sticker and everything. What do you guys think of this?

 

I prefer the duct tape method. Clean the tires and tape a strip of duct tape all the way across the tread down to the wheel (but not on it). You can get a better composite by driving a really long ways compared to chalk, plus you can reach highway speeds where the tire changes shape due to centripetal force. I ended up at 38 front and 30 or so rear when not towing. My wheels are 7.5s and on the narrow side for 33s.
Not responsible for goo left by gorilla tape on a hot day.

BFG publishes the recommended wheel width for a given size tire. The narrow end of the wheel width spectrum tends to wear in the middle more vs wider wheel at the same pressure, BUT your wheels are a little better protected by the bigger sidewall bulge.

 

Quick question and to revive a dead thread.. When you go up in tire size - say 265/75r16 to 315/75r16. How would one expect that to change the "perfect" tire pressure? Would the sweet spot increase or decrease or stay the same. Thanks

 

Another question... With more added weight in the front, such as a steel bumper (100lbs+) is it better to run a higher pressure in the front? Thanks

 

With the same air volume in your tires added weight will increase tire pressure.

 

It sure will. That weight is cantilevered, so it acts like even more weight. Just like towing, you would add air to keep the tread profile where it needs to be. I ended up like 6 lbs more in the front with ARB and winch.

 

So I got a 1st gen. Tacoma (2003) from my son. It's got 215x70x15 tires on it. What??? That's not a truck tire size. He laughs and says that if I want real tires I'll have to spend my own money and buy a whole set of wheels and tires. Even my wifes Hyundai has bigger tires. The 215's I have now are running at 35lbs all around and the sticker for the stock 205x75x15's suggest 29lbs all around. 205's to 215's doesn't seem to be much of a difference. One tire guy suggested 32's all around but this is suppose to be a truck not a car. And yes with these radial car tires - it does handle like a car. Even my old Ford Courier and B2000 handled better. So, reduce pressure or leave it?

 

I think I remember those wheels being pretty skinny, like 6 inches. 35 sounds a little high. The wear pattern will let you know. If they are wearing in the middle, its too high. Since "I love me some" BFG A/Ts, that's what I would recommend when the current tires wear out. You will need a little wider wheel, and then put some 31x10.5 on there. If you have "P" tires on there now, going to a "LT" will make a big difference. Those BFGs have nice stiff sidewalls, and you will not believe how much better it handles. Might ride a little stiffer though. Good luck.

 

I'm not too thrilled with these 215 tires but there's nothing I can do aboiut it yet. These are on stock wheels which are 15" and there's no truck tires that come in 15's unfortunately. To get better tires I'll have to also get at least 16" wheels. I'm been thinking about another 4x4 4runner so I'm not going to spend money unless I have to. Oh well---

 

Im at 30 front and 29 back on E class STmaxx.. at that pressure it rides a lot smother.

 

I'm running my 245-75-16 MS2's at 35 front, 36 rear. DC 4x4. It's what the dealer put them at when they put the tires on my truck. Seems to be ok. Feels a little soft to me and I wanted to bump them up a little, but when I discovered today that I was already at 35/36, I'm gonna stay where I'm at.

It's been my understanding that the front is lower pressure because the extra weight in front (coupled with steering) generates more heat, increasing the front tire pressure more than the rear while driving.

 

Running 275/70/17 what should I run? Got them from Mr. Wheel deal and it's hot here and they are at 42.... Too high?

 

The chalk line method can also be replicated by using masking tape.
Put a strip of masking tape across the tread and put in a day of normal driving; work and back, around town, freeway, what ever is the majority of your normal driving pattern. Then, just like with the chalk line method, see where the tape has worn off. Worn from the middle most, equals a higher pressure, worn fron each edge, equals a low pressure, worn equal across the tape, pressure is fairly right.
The area on which the tire wears changes with speed, so driving your normal pattern before checking the tape or chalk will give a better indication as to average tire wear. The tape method may take longer to see results, but I think may give better indication than a short, 100 yard drive at slow speed.

 

I've been experimenting with my 265/75/r16 load range C Duratracs (on stock TRD Off Road wheels) for a couple weeks now. 90% of my driving is concrete interstates. I carry a good digital pressure gauge. I also have a neighbors tire temp gauge (They're seriously into Sprint car racing and have all sorts of cool toys)

Here's what I've found. When I had 'em mounted, I told the tire guys to start with 34psi. They rode OK, but not fantastic. A fair bit of vibration. Temps went up and pressure went up 3 to 4 psi with highway driving. So I aired 'em down to 30psi. That absolutely KILLED my gas mileage and the truck shook like a bowling ball in a blender. Temps went WAY up and pressure climbed to 35 with highway driving. Back UP to 38 front and back. The vibrations went away. Temps stayed relatively close to starting point. Pressure went up about 1psi with highway driving. At 38 psi, the vibration is gone. Temps vary with ambient air temp and with that, pavement temps. But temps stay close to starting point unless it's stinking hot outside. I'm taking a road trip this weekend and will try 42 psi when I leave, with the knowledge I can air down a bit if the results aren't what I want. Air temps are quite a bit cooler in the last few days, so tire temps will probably look good relative to previous checks. I suspect 42 will be too much, but I have to try.

And yes, I've done chalk test. @ 38PSI I'm seeing just a trace of chalk remaining along the outer 1/4" or so of the tread. I'm thinking 38 to 40 is going to be the optimal pressure.

Ride quality is good at 38psi. Much better than the shaky 30to 34 psi.

3 different tire dealers in my area suggest 40 to 42 psi for Duratracs. They say this is what everyone seems to be happiest with. I'm finding their advice to be pretty much spot on. Even with the higher than expected pressures, I'm satisfied (so far) with the off road performance, even though that has been somewhat limited at this point. Mostly rocks and hard pack clay around these parts. Muddy slick clay in wet conditions. . Not a lot of sand or loose loam. No need (so far) for airing down.

 

Run my hankooks @ 40psi and it's perfect.

 

Thanks for the detailed info. You actually answered my next question. I was wondering how much temp increase, and thus increased psi, one would experience running low vs high starting pressure. Settling into the best results of a chalk test at 30psi is pretty much useless if they're blowing up to 36 on the road. I'm much happier with the 36 now compared to the 30/32 I was running. Really tempted to try the 38 in the front. Not sure I wanna go higher than 36 in the back as I'm already seeing a thread of chalk remaining on the edge at cold pressure.