275-70-16 tire pressure

[kiriln]

I have a 2000 Tundra 4X4 and the door sticker asks for 26 psi front and 35 psi rear. I think the 35 for the rear is when the truck is loaded. Given that the back is much lighter (when empty) I would assume 26 is also OK for the rear tires.

I just got a set of Michelin LTX M/S and find it acceptable to keep the pressure at 26 psi front and back. This gives me a soft ride that my sore back can take.
Is there a risk of running the tires at such a low pressure? Does anybody know the reasoning of why Toyota recommends 26 for the front?

[akauth]

Originally Posted by kiriln

I have a 2000 Tundra 4X4 and the door sticker asks for 26 psi front and 35 psi rear. I think the 35 for the rear is when the truck is loaded. Given that the back is much lighter (when empty) I would assume 26 is also OK for the rear tires.

I just got a set of Michelin LTX M/S and find it acceptable to keep the pressure at 26 psi front and back. This gives me a soft ride that my sore back can take.
Is there a risk of running the tires at such a low pressure? Does anybody know the reasoning of why Toyota recommends 26 for the front?

Probably the biggest reason is to slow down the responsiveness of the front tires. You're less likely to get the vehicle into a roll situation with the lower pressure - Ford did the same thing on their exploders. You're less likely to be able to overreact on the steering. Too, the vehicle will probably track straighter (at the cost of being sluggish).

What's the problem with running that pressure? If you don't check your pressure regularly you *are* going to lose a psi or two a month and you'll get down into the 22 psi range which can be dangerous if you run them too long with too much weight (especially on hot, hot pavement). Too, depending on sidewall design that may also cause excess wear on the outside edges of your tires.

Of course, too. Bumping the pressure that low will hurt your gas milage while increasing the ride comfort.

Most dealers (on any non-HD pickup regardless of brand) will put 32 psi front and rear or thereabouts. You can certainly bump down to less than that in the rear (unloaded) and even in the front you are more likely to get even wear in the 30 to 32.5 psi range. (but no, it's not as cush.....)

Personally, I run about 31.5 in the front with 2 psi less in the rear when it's unloaded. A psi or two more if I'm taking a long trip (where I'm driving 70 to 90 for 4 hours or more).

I try to make sure that my *minimum* cold pressure is always above 28 psi - measured on [approximately] the coldest morning(s) for that time of year.


Alan

[stcj]

The reason for tire pressure to vary, is for even wear across the tire(plus cumfort and performance). Lets say a 265x70-16 tire mounted on a 16x7" rim carrying 1200lbs uses 26psi. That same tire mounted on a 16x8" rim must have more air in it or there will be too much wear on the outer porsions of the tread and not enough in the center. Also if that same tire with 16x7" rim is move from the front to the back while carrying 1500lbs, must be inflated higher for the same reason. Even wear across the tread surface. Just my .02