Correct Tire Pressure? [850][94]  ... posted by David Emanuel  on Tuesday, 6 March 2001, at 11:49 p.m.
 

         Hi, I have a 94 850 Turbo Wagon and inside the gas hatch there are markings for the correct tire
         pressure. It says 36 for the front and 41 for the rear (in PSI's). Since buying the car with about 55,000
         miles on it 3 years ago, I now have about 110,000 miles. In otherwords, I've doubled the milage. In that
         time I replaced my first set of tires the month due to 2 blow-outs and worn out tires. My first set after
         that was the Dunlop Sport 8000, but they wore out in about a year. My second set, which has been
         much better has been the BFG T/A Touring VR4. But these are about worn out now and I will have to
         get new tires within a month or so. My question is in regards to the treadwear. Both sets of tires wore
         out on both the inside and outside edges, . My passenger side tire has worn more on the inner edge. The
         tread in the middle of the tires seems to have some depth left. What is strange is that I've been
         maticulous about keeping the air pressure 36 in the front and 41 in the rear and have rotated the tires
         every 5000 miles, minimum. The very center of the tires seem worn much more than the rest of the tires,
         except for the edges. More than one mechanic has commented that the tires look as if at times I've
         severely under-inflated them, and at other times, over-inflated them. I know this isn't true. Does anyone
         know what may be causing this? I've had the alignment checked several times with no problem. On my
         first set of tires I used the 205/50/16 size and after the "refund" (snarl....) I went to the 205/55/16 size
         with the BFG. I rotate back to front, but am considering cross rotating on my next set of tires. I'm
         concerned that with the larger tires, I don't need to use the 36/41 PSI and would like to know what
         others are using for their air pressure. Some comments with PSI front/back and tread life would be
         appreciated as well as your opinion on front to back rotation or cross-rotation of your tires. Also, I'm
         considering getting the new Kumho Ecsta Supra 712 V-rated tires, BFG g-Force T/A KDWS, or the
         Dunlop SP Sport 5000's. What do you think? All have good ratings on Tire Rack. I'm interested in
         doing everything I can to keep from having to change tires every 12-24 months.
 

.. posted by Ray Niblett  on Wednesday, 7 March 2001, at 12:05 a.m. ...in response to
         "Correct Tire Pressure?" posted by David Emanuel.
 

         There should be two pressures listed. The high numbers are for
         gas milage ratings. The lower numbers are more realistic. I
         use about 33 PSI front / 30 PSI rear on both our Volvos (I add
         a couple pounds for high-speed trips when the whole family
         is in the car along with luggage). My tires have worn fairly
         evenly with front/back rotation considering they are front-wheel
         drive cars. I do have more wear on outside edges. I replaced the
         Michelin XGT V4 tires on my T5 at 23K (about normal for a
         performance tire) and the GLT went 34K on the OEM Michelins MXV4
         (a touring tire).

         Check the tire sidewall, too. It will have a max inflation value
         that should NEVER be exceeded. Mine say 40 PSI, max. Your rears
         are way over-inflated.

         --
         Ray Niblett 95 855 GLT / 98 S70 T5M

... posted by Jeff S on Wednesday, 7 March 2001, at 7:12 a.m. ...in response to "Correct Tire
         Pressure?" posted by David Emanuel.
 

         My wife's 850 suffers from the same type of tire wear, I think the passenger front is more pronounced.
         When I bought the last set of tires, I inflated the pressure to 35 psi (max listed on tire sidewall). In less
         than 5000 miles the inside and outside edge of the front tires where almost down to the wear bars. The
         rear tires looked perfectly new, still had moulding nubs on the tread. I rotated the tires (front to rear) and
         inflated the fronts to 40 psi. The front tires (previously rear) were showing the same type of wear so I
         upped the pressure to 45 psi. I have managed to reduce the wear on the edges (it still seems to be faster
         than the center), but the center of the tread still looks relatively new.

         Since these tires have been on the car I have replaced: shocks, upper strut bushings, ball joints (the car
         is a '93 model), sway-bar end links, tie-rod ends (alignment afterwards, but they didn't give me a report
         on the values). This is just speculation but it could be suspension parts that are worn creating the
         problem. I may have fixed my wear problem but I can not be sure since the tires were pretty messed up
         before I started making changes. What I can say is that I seem to have slowed the wear rate down with
         the various things I have done.

         If you do solve the problem, please let everyone know.

... posted by Ray Niblett  on Wednesday, 7 March 2001, at 10:46 a.m. ...in response to "Tire
         wear" posted by Jeff S.
 

         Someone once posted here that TireRack recommended doing the
         first tire rotation at 3K then go to 5K rotation. Maybe the
         first 3K miles heavily influences the wear patterns?

         --
         Ray Niblett 95 855 GLT / 98 S70 T5M