Air pressure in 10 ply tires

A good place to start is the recommended PSI for the factory tires. Carrying capacity is based on PSI. The numbers on the drivers door for P rated tires is right around 30 PSI +/- a little, I can't remember and don't want to go out and look. That number is for best ride. The number stamped on most P rated tires calls for 44 PSI to meet the trucks payload.

Even when I had P rated tires on my truck I tended to run just under 40 PSI. If I'd run them closer to 30 PSI it would have given a better ride, but every time I hauled something in the bed I'd have had to air up and then air down when finished. I chose to run them a little closer to the max on the tires sidewall because I tend to carry something in the bed pretty often. I found 38-40 PSI to have acceptable ride and they handled loads better than 30 PSI. Got a little better fuel mileage too. Lots of guys concerned about over inflation and wearing out tires. I was always able to get right around 60,000 miles out of a set so I'm good with that.

When I changed to E rated tires they are rated for much heavier loads. Far more than you'd put in a Tacoma. You actually need less air in an E rated tire to meet the same payloads. Most guys running 3/4 ton trucks run about 50-60 PSI unloaded and 85 when loaded heavy. On my Tacoma I found about 35 PSI did about the same thing for me with E rated tires that 40 PSI with P rated tires without making the ride too harsh. There is no reason to try to put 50 PSI in a tire on a Tacoma, and the rims aren't even rated for 85 PSI. You could probably do fine at closer to 30 PSI. But you just have to experiment and see what works best for you.

 

What you mean by "math" puts me at 41 psi? And why LTs arent for me? I need them as i go to remote places with sharp rocks.

 

Toyota recommends that in the factory supplied P rated tire. That does not apply when going to an LT with a E load rating.

 

37 warm 285-75-17 BF goodrich K02 with steel bumper/winch & frame sliders.

 

https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

That document will give you all the info.

 

I haul heavy gear in bed when traveling but I think I'll go down to 37 and see how it rides. For some reason my tires just look "low " under 40.

 

Do the math or don't, they are your tires. For the OP, the math works out to 37. Deflate to 20 on rough trails for a smoother ride and more grip.

 

Interesting man, ill give that a good read. I always ran e rated in my trucks and followed the manufacturers PSI. They wore great, lasted a long time, and never looked "low" .

 

This intuitively makes more sense to me then the chalk test.

 

But if its the same diameter tire, why would you run higher pressure? Am i missing something?

 

Well no need to do the math since you did it for us. Not sure who you are talking to.

 

LOL, not you and nobody in particular, just anyone that wants to argue with the math. It will give the right answer based on the manufacturer's recommended rating for the OEM tires. But, some people choose to vary from that for their own reasons. Keep in mind the math is different depending on the tire size you are running, I just happen to be running the exact same as the OP.

 

See post #5.
It and the Toyo PDF I posted a link to, explains it.

Proper inflation on your LTs doesn't sound comfortable for you.

If I convert your current LT psi to your stock tire, it is the equivalent of inflating your stock tire to 21 psi; more likely, even less. I knowingly made the assummption the charts are linear; they're not. You fall way off the charts...

 

Ok. I'm just terrible at math. Like really terrible and those charts are like Chinese to me. I take everyone's input and advice and do appreciate it. I definitely dont argue with math. I admire those who "get it".

 

What are we really doing when we change psi?
PSI is a means to an end; inflated load capacity.

 

I did the " Feel's Good to Me" test. I think each truck is different. Weight in the front vs rear vs both vs up/down vs …. opinion. 31.28 for me

 

I'm not terrible at math and I even got it wrong the first time around because I didn't account for the euro de-rating that @splitbolt pointed out. He helped me fix my math. But, now that he's done it to get to the right starting point, just looking things up in the tables for your particular tire size is all you need to do.

 

Thanks man, ill give it a read tonight.

One thing i dont get, i always ran the PSI thats in the door jamb, always, and ran E load tires. I never had any issues, ever and tires lasted me a long time. One would think if its under inflated it would hurt mpgs, be noisy and wear out quicker. Thats the part that confuses me a bit. I will definitely look into it as im very curious, maybe i was doing it wrong the whole time, ha!

 

I think there is a large margin of error. As long as you aren't too far off, you will be fine. Also optimal air pressure can be defined different ways and is dependent on conditions (e.g. on road vs off road).

 

I agree, but lets say we talking about on road driving. What would be the optimal E load psi? Honestly i did try higher pressure and it was horrible. Im gonna read those pdfs but i suck terribly at math. One of my least favourite subjects haha!