Tire pressures for 285; I think BFGoodrich may be a little high?

[Mighty Hd]

Cupping typically indicates that the shocks are either worn out or not doing their job. The job of the shock is to keep the the tire surface contact with the road.

The dealer checked them at 10k, again at 15k and right before Discount tire warrantied out the 275's that were cupped. I also had 5 alignments done by the dealer, and checked just after I put the 285s on. No problems according to them; also, I did not see any fluid leaking from the shocks.


But..shocks going bad at 32k ???

In my work truck (company owned F-150 SCrew 4wd): It has 285s firestone MTR's. The truck had 10 miles when the tires were installed and they were cupped like a mother by 5k. Took it to the dealer and all checked out?? I now live with the *** *** ***.. :-(

 

[iLikeEggs]

Probably not, I didn't know your mileage. On a newer vehicle it's possible but not likely then that it's the shocks.
Sounds like the front is is checked and tight, as it should be at 32k.
Are the new tires cupping as well? If not then it was likely it was a structural defect in the tires or just design flaw.
Bottom line with air pressure, under inflated tires will produce excessive even wear around both outside edges of the tires. Over inflation will provide excessive wear down the center of the tire tread.
It could be that the particular brand/model tire on a particular truck will just never ride or wear right. Sometimes this happens. All things being equal with other Z71's, you may have to try a different tire to get the handling characteristics you want.
If everything else is good with the front end (and I still wouldn't rule out the shocks) it will come down to the tires.

 

[BlkYukon]

I had BFG KO2's on my Silverado, same 285/65-18 size

I liked them best when I set the fronts at 44psi and rears at 40psi

 

[Fish-man]

Off the door jamb:
GVWR: 7300lbs
GAWF - FT -- 3600
GAWR -- RR -- 4100

Your P265/65R18 tires are rated (actually de-rated by 1.1, since its technically a car tire on a truck) at 2469/1.1=2245lb per tire at 35psi. The LT285/65R18 tire is rated at 2235lb per tire at 40psi. So by worst axle, you would have a 'reserve' of 370lb if you ran the LTs at 40psi.

know that what you stated in one of the other posts is a little bit incorrect. Know that for standard load "P" tires, the maximum pressure you get load carrying capacity is 35psi... so you show it at 51, which is the same load capacity as 35. The 51 is simply what the mfr says is the max pressure you'd ever want to put in that tire.

Remember that your TPM will continue lighting up as 'low', based on the oem pressure.