Tire Load Ratings

Ha!! It was a cold night on that mesa and I would have welcomed a hooker or 3 to stay warm.

 

Thanks everyone for the advice and debate. I did the tire pressure calculator on TireSize.com and it recommends 30psi. I'll give that a try and see how it rides.

 

It's an uncanny coincidence but the sticker on the Tacoma door jam also says 30psi.

 

Yeah, E's get you much better protection for sharp rocks, etc, even when aired down. I bought Discoverer AT3 E's and researching them some guy on IH8mud I think it was dug deep into the ply thickness, called tech support for various mfg's. E's were something like 3-plies @ 3mm each, don't remember all the details but you get thicker plies in E's. May be 3-ply same as a C or D, but each ply is thicker. Roads like that the difference is needing the plug kit and spare or not.

As people have said, tire size, tread choice and brands limits choices sometimes. E's are ok with me, ride quality onroad is different because there is less sidewall flex cornering even at 35psi.

 

I'm betting something got entered wrong. When switching from SL tires to LT tires the same size, it normally recommends a higher pressure for the LT tire.

 

Yes sir!! We all gotta get along for sure, especially in today's crazy world. We may not all agree on everything but most of us here love these trucks.

E rated for the win though!..fer haul'n AND offroad'n, not pose'n.

 

I went up from 245/75 C to 265/75 E tires.

 

Right, but your stock tires were probably SL, which is what you should enter into the calculator. No Tacoma comes with LT tires unless it's a dealer add-on. The first part of the calculator should be filled in with the information from your door jamb.

 

I don't argue facts; I just lay it out there. What people do with it or how it is construed, is of no real concern to me.

The full version chalk method at least tries to make some allowances for deflection(equalize) and dynamic loading(add 10%). The short version is not much better than a static footprint.

 

As stated before E rated tires at considered 10 ply the max air is above the standard tire/ the inflation should be at the truck manufacturers rating on the door post. The tire manufacturer didn't build the truck/car.

 

This is incorrect. LT tires require more pressure than SL tires, even for the same load. It is based on the OEM tire pressure recommendation, but it will be higher. For example, my 4Runner came with P265/70/17's and runs at 32 PSI, but with LT265/70/17's it requires 44 PSI. Even my 295's require 35 PSI to maintain the proper load rating.

The second part of your post is absolutely correct. The tire pressure is based on GAWR (edit: or, GVWR), not the tire's maximum inflation.

 

Look at the GAWR for the Tacoma. Both ratings added will exceed the GVWR.

Are you really sure the tire air pressure should be based on GAWR???

I'm skeptical.

 

I suppose it could be based on GVWR since it appears to be the same for front and rear.

I thought my 2nd gen recommended 29 front and 32 rear, so I assumed it was based on GAWR.

Either way, the point is that it's based specifically on the vehicle and tire size/type, not the tire's maximum inflation.

 

When spec'ing a tire for a vehicle, it must be capable of supporting GAWR.
Recommended pressure is based off GVWR and dynamic load factor.

GVWR=5,600
P/euro-metric tires @ 2,154 lbs recommended inflation psi x 4 tires = 8,596 lbs
8,596 ÷ 5,600 = 1.54 dynamic load factor

LT tires @ 1,954 lbs recommended/adjusted inflation psi x 4 tires = 7,816 lbs
7,816 ÷ 5600 = 1.4 dynamic load factor

Combined GAWR on my Offroad is 6,190 lbs. Any way you slice it, the recommended PSI has a dynamic load factored in. GVWR is still the ultimate weight limit...

OEM Offroad tires at max load inflation capacity PSI is 9,876 lbs. This occurs @ 36 PSI, despite the max inflation listed on the tire. Anything between 37 and 44(?) PSI is meant to maintain speed rating

 

stuff like that is why I always get “E” tires. All it takes is getting a flat on a mountain pass like Engineer Pass or a forest road and you’ll want tires that can handle the terrain, been there, had that happen.

 

You don't need to run LTX's - Not everyone wants to run such a street-looking tire. There are lots of SL rated, chunky looking tire that don't weigh 65lbs.

 

The best pressure on any tire is one that will keep even pressure across the tread. Too much pressure and the middle will wear. Too little and the outsides will wear. That's why so many here have advocated for years to use the chalking method. It allows you to customize the pressure to get the most rubber on the road and spread the load evenly. This method will work for any tire type.

 

You'd get a much better ride, and gas mileage. I run my 265 75 16 Duratracs at 32 psi

 

My C Load Duratracs are 6 ply. I believe (don't quote me), E load are 10 ply