I bought a 2004 Forester with Yokohama Geolander G900 tires. The
dealer delivered the car with 40 PSI in the tires, which is a lot
higher than Subaru recommends. (Subaru says 29 PSI front and 28
to 36 PSI rear, depending on load.) The tire sidewalls state that
these tires can handle pressures of up to 44 PSI.
Is there any advantage to using a higher tire pressure than Subaru
recommends, or is my dealer just crazy?
Kenneth Almquist
The pressures that Subaru recommends 29 PSI Front / 28 PSI - 36 PSI Rear (depending on load)
are recommended for good reasons. Safety, handling, optimum traction, comfort, proper alignment and optimum tread wear are those reasons.
So, if the dealer delivered the vehicle with 40 PSI in all 4 tires, then the vehicle was improperly prepped for delivery!
I recently purchased a set of Pirelli Cinturato P7 All Season Plus tires for my 04 Forester, and Pirelli specifically states that the vehicle manufacturers recommended tire pressures must be used in order to to maintain the tread wear warranty of their tires. Additionally, Pirelli states that these tires must be rotated every 5,000 to 7,000 miles to maintain the tread wear warranty, which is more frequent than Subaru's recommended rotation intervals. So, I'd advise using the pressures that Subaru recommends, and the rotation intervals of the individual tire manufacturer to get the most safety, and tread wear from whatever tires an individual decides to purchase for their Forester.
I'm running the recommended 29 PSI Front / 28 PSI Rear in my Forester's tires, and the vehicle rides and handles very well. I only haul around my Great Dane, and an occasional passenger and groceries so, the higher tire pressures in the rear tires aren't needed under the conditions in which I use my Forester. I'm also using a 6,000 mile rotation interval as recommended by Pirelli to ensure that I get the most tread wear from my set of tires.
Using higher than recommended tire pressures will in fact decrease the vehicle's fuel consumption, but the safety, handling, ride comfort and tread wear of the tires will be negatively compromised by doing so.