Help!! My tires rub my fender! 285/75/16 on an 02 Tacoma

Solved my rubbing issue. Did the fender Mod. Pics coming soon.

Anyone tell me what tire pressure I should be running on the 285/75/16s?

How do I calculate what my new tire pressure should be now that the door panel is irrelevant?

 

for normal daily travel...
I ran 34 psi up front
32 psi out back (34 psi with load)

you can use some chaulk or paint
lay a line across the tread's cross section...
and see if the tread is rolling flat.

If the outer chaulk mark is untouched...
there is too much air in the tires.

If the the tread's center has less chaulk worn/removed...
then the psi may be to low and the tire may be cupping

you want all of the tread to roll as flat as possible
so that it wears evenly and stays in contact with the surface.

slight over inflation could improve fuel mileage tho' offer a harsher ride
but under inflation, tho' a better ride, could cause accelerated/uneven tire wear.

Be sure the alignment is up to snuff

 

I run 25 psi for normal driving. I rotate and balance the tires often to help with possible uneven wear.

 

There is science behind this.

I can intuitively deduce the following:

- The amount of tire pressure required depends on vehicle load (among many other things listed below)
- The optimal pressure @ a given load for street driving will be the one which yields the optimal contact pattern to result in even wear.
- The pressure vs load relationship is going to be different for different models and sizes of tire.
- The stress vs strain (i.e tire load vs tire deformation) behavior for a given tire cannot be deduced from the max inflation pressure at max load. One point on a curve does not give you a curve, it gives you a point!
- Also, the relationship between tire deformation and road contact pattern depend on multiple engineered aspects of the tire construction.
- All above things mentioned are dependent on Ambient Temperature, Atmospheric Pressure, Vehicle Speed (temperature due to changes in frequency of material shearing cycles), and driving conditions (snow, ice, water, terrain).

From these observations I conclude that you cannot calculate required pressure for a different size tire without knowing all the technical details of the engineered tire.

The only thing that a common person can do is perform a test to find what they need for their particular application of the tire. Typically OEM specifications are based on road tests performed by the manufacturer at nominal driving conditions they expect the customer would use.

The chalk line test sounds like a good one to get you pretty close.

I think what I am going to try is take a paint marker and paint a line across my tire tread and see how it wears after a day of driving and then make adjustments accordingly.

 

So here it is with my wheelset finally installed. I had to do some fender trimming. I'll send my pictures of that soon too.

 

Looks good man, glad you got everything worked out.

Did I miss what the rear setup was? Also what's the BS on your wheels.

 

I have the Toytec OME 3" lift with leveling kit. I used an AAL and nitrochargerxs in the back.

My wheel BS is 4.49". I have no frame rubbing issues. I had to do the pinch weld mod to get my tires to work. I still have to trim a little more too.

 

Looks good. Let me know where else you are trimming. I'm ordering 285s soon so I'm curious where you are trimming.

 

Looking good!
Go to the Old Man Emu: Questions, Answers & Pictures ( 1 2 3 ... Last Page) & post some pics & your specs.
We need more 1st Gen info.

 

I'll post some pics of exactly what I had to trim, once I get everything done.