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

[Mighty Hd]

Hello. I am hoping that someone here more experienced could provide some insight.

I have a 2013 z71 Tahoe with factory 18" wheels. Original tire size was 265-65/18

I was running a 275 BFG AT KO for about 30k. Long story short,money were impossible to balance and wore to 4/32nd tread in that 30k. I always ran 40-45psi. The last 10k was at 45psi due to the fronts chopping and wearing terribly. Rotations every 5-8k and had 3 alignments done.

Now that I have a set of new AT KO2 in a 285-65-18, I am unsure what an acceptable tire pressure is. The tire shop set them at 40k, but it feels like the vehicle wanders and tracks slightly.

I contacted BFGoodrich and requested information regarding the tire pressure. I gave them the original tire size on the vehicle there specified 35 PSI and of course indicated that I now have the 285 tires.

BFGoodrich responded and said that I should be running the tire is it 50 psi. I am thinking that is a bit high?

With some of you kindly chime in and advise your experience or what you have been recommended to run your 285 BFGoodrich all-terrain's at?

 

[Fish-man]

50 sounds high. But, these thick heavy tires do need higher pressure to hold same loads. If you can look for the gross axle weights, I can help you figure out how much pressure you need.
On my avalanche with 285.70r17, I run 36psi.

 

[iLikeEggs]

What load range is the tire? That will determine what psi you should be running. If you are running standard size tires and standard load range then stick with the manufactures recommendation on the door jamb. Otherwise, check out this: http://www.tirereview.com/tire-types-and-load-capacity/

Also, Tire Rack has a nice reference section section a load range chart: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=55:

Manufacturers and most tire shops will only recommend factory specs on tire pressure and sizing because of liability. When tire sizes and psi are altered the handling characteristics of the vehicle change from the original intent of the design and equipment. It's muddy water for them. If they tell you to vary from OEM specs it means they sanction those changes which makes them liable when the handling characteristics change. This holds true for most chains. Some shops don't care, or are specialty and carry different insurance. Your mileage may vary.

 

[Mighty Hd]

What load range is the tire? That will determine what psi you should be running. If you are running standard size tires and standard load range then stick with the manufactures recommendation on the door jamb. Otherwise, check out this: http://www.tirereview.com/tire-types-and-load-capacity/

Also, Tire Rack has a nice reference section section a load range chart: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=55:

Manufacturers and most tire shops will only recommend factory specs on tire pressure and sizing because of liability. When tire sizes and psi are altered the handling characteristics of the vehicle change from the original intent of the design and equipment. It's muddy water for them. If they tell you to vary from OEM specs it means they sanction those changes which makes them liable when the handling characteristics change. This holds true for most chains. Some shops don't care, or are specialty and carry different insurance. Your mileage may vary.

They are a load range E tire. OEM tires were Goodyear SR-A Load Range C 265 65 18.

I had a hell of a time with my old BFG's cupping. I ran them between 40-45psi.

I put 48psi in them for now and will ride around today to see how it rides. I did the chalk test when they had 40psi and it appeared to be even...but it was difficult to tell to be quite honest.

 

[Mighty Hd]

50 sounds high. But, these thick heavy tires do need higher pressure to hold same loads. If you can look for the gross axle weights, I can help you figure out how much pressure you need.
On my avalanche with 285.70r17, I run 36psi.

I found this online.. Will this help?

Curb Weight - Rear (lbs) 2736
Gross Axle Wt Rating - Rear (lbs) 4100
Gross Vehicle Weight Rating Cap (lbs) 7300
Curb Weight - Front (lbs) 2958
Gross Axle Wt Rating - Front (lbs) 3600 Gross Combined Wt Rating (lbs) 11000

 

[01Konvict]

That does help and try this info

http://www.4wheelparts.com/tire-wheel-package-guide/tire-pressure-checker.aspx

 

[Fish-man]

It would be best if you found it on your truck. Should be on a grey sticker probably in the door jamb

I found this online.. Will this help?

Curb Weight - Rear (lbs) 2736
Gross Axle Wt Rating - Rear (lbs) 4100
Gross Vehicle Weight Rating Cap (lbs) 7300
Curb Weight - Front (lbs) 2958
Gross Axle Wt Rating - Front (lbs) 3600 Gross Combined Wt Rating (lbs) 11000

 

[Mighty Hd]

It would be best if you found it on your truck. Should be on a grey sticker probably in the door jamb

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

 

[Mighty Hd]

http://forum.ih8mud.com/threads/tire-inflation-the-ultimate-answer.111671/page-2

I found a post indicating a pressure range of 10%. ie: if the tires are underinflated, the temperature would be less than 10%, underinflated, over 10%.

I have mine at 48psi now. After about 15 miles of driving, 80deg ambient temp and around 48% humidity my tire pressure was respectively 52 all the way around. It also drove a lot different and felt like it required much less throttle to keep rolling versus 40psi. It also felt more stable on the road and not wandering.

For what it's worth I guess?

The 4wd parts math:

Original tire: Goodyear SR-A P265-65/18
Recommended PSI: 35
Load: 2469lbs @ 51psi
Weight: 35lbs

Upgrade tires: BFG AT KO2 Load Range E 285-65/18
Recommended PSI: 50 as per BFG Customer Service
Load: 3640 @ 80 psi
Weight: 58lbs

I can't really compare as I do not have a tire chart for either tire...........

 

[iLikeEggs]

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.