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Since this came up yesterday, I thought it would be a good thing to share.
Most people assume the tire shop knows (or cares) what PSI you should run in your aftermarket tires.
Most shops fill according to the door sticker or close to the max of the tire.
For example, I just got BFG KM3s on my Ram 2500 yesterday. The off road shop who installed them is legit. Owner races Trophy Trucks and they do a whole lot of work in the area.
They filled each corner to 65psi.
Each tire is rated at 3,970lbs @ 75psi.
At 65psi, this equates to 13,763lbs capacity. (65psi is 87% of the 75psi max. 87% x 3,970lbs = 3,441lbs. 3,440.67lbs X 4 = 13,762.67)
GVWR is 9,000 for my truck.
At 65psi, I'd riding around with enough pressure in my tires to support 4,762.67 additional pounds. No Bueno.
The Door sticker has 50 psi front and 70 psi rear.
These tires inflated per the door sticker support 12,704lbs (3,704lbs excess).
70psi in the rear it is a a miserable ride. When I tow a trailer (especially my gooseneck), I'll air up for sure but in a pickup with no load in the back, you're generally going to run less in the rear than in the front. (the distribution is more front biased in a diesel due to engine weight)
At 45psi front and 40psi rear, I'd be running at 8,998.67lbs (almost exactly GVWR).
At 50psi front and 45psi rear, I am running 10,057 about 1,057lbs over GVWR. Ride is good, steering is tighter, provides a margin of error for overloading and tires should wear evenly. (anywhere between these two settings should be fine)
This is a great write-up on this and goes into much more detail.
https://carlisuspension.com/tires-and-wheels-how-do-they-affect-my-ride/
* this calculation method is for on road PSI. Off road is situational. Example: I my buggy, I run 7-10 psi front and 4-6 rear on 39" Red Label Krawlers with beadlocks.
Hope this helps someone.
Most people assume the tire shop knows (or cares) what PSI you should run in your aftermarket tires.
Most shops fill according to the door sticker or close to the max of the tire.
For example, I just got BFG KM3s on my Ram 2500 yesterday. The off road shop who installed them is legit. Owner races Trophy Trucks and they do a whole lot of work in the area.
They filled each corner to 65psi.
Each tire is rated at 3,970lbs @ 75psi.
At 65psi, this equates to 13,763lbs capacity. (65psi is 87% of the 75psi max. 87% x 3,970lbs = 3,441lbs. 3,440.67lbs X 4 = 13,762.67)
GVWR is 9,000 for my truck.
At 65psi, I'd riding around with enough pressure in my tires to support 4,762.67 additional pounds. No Bueno.
The Door sticker has 50 psi front and 70 psi rear.
These tires inflated per the door sticker support 12,704lbs (3,704lbs excess).
70psi in the rear it is a a miserable ride. When I tow a trailer (especially my gooseneck), I'll air up for sure but in a pickup with no load in the back, you're generally going to run less in the rear than in the front. (the distribution is more front biased in a diesel due to engine weight)
At 45psi front and 40psi rear, I'd be running at 8,998.67lbs (almost exactly GVWR).
At 50psi front and 45psi rear, I am running 10,057 about 1,057lbs over GVWR. Ride is good, steering is tighter, provides a margin of error for overloading and tires should wear evenly. (anywhere between these two settings should be fine)
This is a great write-up on this and goes into much more detail.
https://carlisuspension.com/tires-and-wheels-how-do-they-affect-my-ride/
* this calculation method is for on road PSI. Off road is situational. Example: I my buggy, I run 7-10 psi front and 4-6 rear on 39" Red Label Krawlers with beadlocks.
Hope this helps someone.
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