Tire Pressure

DiscoArt

Well-known member
Nov 14, 2009
97
0
I just got a set of BFG A/T 265/75R16 tires and the shop put 40psi in them. Max PSI on the sidewall is 80. The tires don't look under inflated with 40psi in them. Any recommendations on what the pressure should be for D2?
 

discopedro

Well-known member
Jul 16, 2008
812
0
las vegas,nevada
In town I usually run my 245/75's at 30 in front and 40 rear. Hwy I'll air up to 40frnt and 50 rear. I feel every bump on the hwy, but I'll take the mpg improvement. IMO on our vehicles there is no reason to run anywhere close to max psi.
 

clarkwjackson

Well-known member
Oct 22, 2007
145
0
UT
39 ft 45r

Used the Michelin load/inflation Tables. The rule of thumb is never inflate lower than original (size) tire pressure. The tables help you determine adequate pressure for different size tires. First, find the size tire equipped stock and its pressures then look up that size/inflations in the table...this gives you the load capacity you are trying to maintain. Next , look up the new size tire, follow the load capacity until it meets/exceeds the stock load and refer to its associated pressure. I've been running this pressure setup through 2 sets of LT265/75r16 and they wear just fine and I'm getting about a 70k average on my bfg at.
 

clarkwjackson

Well-known member
Oct 22, 2007
145
0
UT
I have the hardcopy michelin data book. I'll see if I can find a link on the interweb...

Edit: can't access the Tire and Rim Association website anymore (login no longer accepted). I'll have to try scanning the hardcopy I have when I get home...
 
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clarkwjackson

Well-known member
Oct 22, 2007
145
0
UT
Ok here are a selection of the tables that are pertinent to load/inflation of stock disco to LT245, LT265, and LT285. This is a little more general table than I've had in the past (the pressure increments are much wider on this table) unfortunately I don't have that book here and no longer work full time at the tire shop I used to run.

The method with these tables is:
1. determine stock size (and in this instance load index #)
2. determine cold tire inflation front and rear of stock size
3. refer to stock size in load/inflation table (in this instance determined by load index #) to find load (stock) at pressure (stock)
4. refer to LT Metric load/inflation table for tire size in question
5. match stock load front and rear with the LT load (also front/rear)
6. apply tire pressures as indicated

RULE of THUMB:
Now, I haven't gone over the numbers in this set of tables to be sure but sometimes a tire carries the same load or a greater load at less than the stock tire pressure. The rule of thumb is NEVER INFLATE A PLUS SIZE TIRE TO LESS THAN THE ORIGINAL (STOCK) TIRE PRESSURE FOR ROAD TRAVEL.
**disclaimer** I know there are a ton of people who run a low tire pressure in oversized tires and have never had a problem. I also know a lot of skiptards who have had tire failure, loss of control, etc. This is the way I learned it at every Michelin/BFG/Bridgestone seminar i've ever attended. The main cause of tire failure is due to underinflation/overloading...in fact its printed on most tires sold in north america.

http://picasaweb.google.com/clarkwjackson/LoadAndInflationTables?feat=directlink

edit. sorry it took me so long to get this stuff posted, we just had our first baby a week ago monday, so I've been a little preocupied.