Tire Pressure for a Fat Tacoma

[OldManJack]

Gents,

I have added steel, front and rear bumpers, fiberglass rooftop tent, 270 and shower awnings, rear canopy (topper) on my 2014 Toyota Tacoma. Currently with all this new weight and all my gear, water, propane and extra fuel cans, the total weight is 6,450lbs.

I am nervous that I have too much weight. I know that's not the best situation as being 1k lbs lighter would be better, but I'm going to give it a shot and see how she does. I have added new suspension system (Old Man EMUs) on her and added some Timbren SES bump stops which should help with stability and keeping her from bottoming out. I just put on her a brand new set of Nitto Ridge Grapplers LT285/70R17s.

With that in mind, what would you recommend my highway psi be set at, and when I hit the off road, what should I air the tires down to?

I'm thinking of starting at 50psi/front and 55psi/rear for highway and 25psi/front and 30psi/rear for backroads and seeing how she does.

Thanks,

Jack

 

[diabetiktaco]

Gents,

I have added steel, front and rear bumpers, fiberglass rooftop tent, 270 and shower awnings, rear canopy (topper) on my 2014 Toyota Tacoma. Currently with all this new weight and all my gear, water, propane and extra fuel cans, the total weight is 6,450lbs.

I am nervous that I have too much weight. I know that's not the best situation as being 1k lbs lighter would be better, but I'm going to give it a shot and see how she does. I have added new suspension system (Old Man EMUs) on her and added some Timbren SES bump stops which should help with stability and keeping her from bottoming out. I just put on her a brand new set of Nitto Ridge Grapplers LT285/70R17s.

With that in mind, what would you recommend my highway psi be set at, and when I hit the off road, what should I air the tires down to?

I'm thinking of starting at 50psi/front and 55psi/rear for highway and 25psi/front and 30psi/rear for backroads and seeing how she does.

Thanks,

Jack

I had a similar setup with OME HD Dakars, 885's, and nitrochargers. I usually ran 35 psi and never had an issue or instability. That was on 255 / 75 - 17 tires.

 

[madcratebuilder]

Google "Tire chalk test" This gives you optimum psi for your rig. I run a tall 10 ply and I'm 31F/30R. Seems low at first look but I'm getting even tire wear and ride is smoother than when I ran the recommended 36 psi F&R.

 

[OldManJack]

I never knew about this chalk test. Makes a ton of sense. Thanks.

 

[MMc]

I never knew about this chalk test. Makes a ton of sense. Thanks.

I would do one empty and one with your rig as if you were on the road.

 

[DRAX]

Something else to look at are the inflation and load charts from the tire manufacturers. They will tell you the minimum required PSI for a given load on the tire in order to run it at the rated speed. From the vehicle manufacturer, the OEM tires and tire pressures are what is needed to provide the necessary load capacity for the vehicle's GVWR or GAWR. Once you change away from OEM tires, exceed factory GVWR, etc, then things can change and these inflation charts can give you a good starting point. For the OP, the below should apply. If the rear axle load is over 4,210LB then they have to run more than 35PSI on the highway. If it's less than 4,210LB then the tires will be fine to run at 35PSI on the highway. Fine-tuning with the chalk test isn't a bad idea once you're in the ballpark based on tire/axle load.

LT285/70R17 Tire Pressure

Discover the load limits at various inflation pressures for LT285/70R17 tires to ensure optimal tire performance and a safe drive.

tirepressure.com

Tire Size	35 psi	40 psi	45 psi	50 psi	55 psi	60 psi	65 psi	70 psi	75 psi	80 psi	95 psi
LT285/70R17 Single Tire	2105 lbs	2315 lbs	2510 lbs	2755 lbs (C)	2900 lbs	3050 lbs	3195 lbs (D)	3195 lbs	3195 lbs	3195 lbs (E)