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Air pressures in tires on my 2007 xc90 4.4L V8

1K views 13 replies 6 participants last post by  Paul1963 
#1 ·
I’ve read that because the xc90 cars are so heavy that some are going up in pressure to 40-41 lbs from 36 as listed on the door pillar
This solves the problem with outer edge wear as the tires seem to be under inflated for such a heavy car and now with the higher pressure the tires treads ride more flat to the road
 
#2 ·
Not sure where you heard that, but going higher in pressure is okay if you have XL rated tires and/or are carrying extra weight. I used to run ~38psi since I do a good amount of interstate travel and the center of my tires wore out faster than the outer edges. Those were with 17in tires which will roll more on the sidewall and I am known to drive my XC90 like a BMW. I now run 18in tires using 36psi. Don't have personal experience with the V8 weight, but maybe you might do better with 37-38psi, not the 40-41psi.

If your tire sidewalls are rolling too much or are getting too much outer edge wear, then it might be time to look at worn suspension components and/or the type of tire you are using. Most crossover/SUV tires are designed to handle our weight, but the cheaper ones might not be. Don't use tires designed for a minivan or car.

Add pressure when it is getting cold, otherwise, try to stay around the 36 or so. Also, in any AWD, I like to use consistent psi in all 4 corners.
 
#3 ·
I run 39psi in our V8, it helps a little with the outside wear, never had the centers wearing faster than the front. Maybe 40-41 is the right way to do it?

regarding all the way around for AWD, I have had other AWD cars and non-staggered sizes and OEM has different pressures listed front-rear. All depends on how much weight is on each axle
 
#4 ·
What suspension and tires do you have?

As far as the OEM recommendations, yes they may have different pressures for different axles. However, from my experience, for when the AWD kicks-in, I've had better and more consistent results with equal tire pressures....but like you said, if you are towing or have extra weight, then increasing the pressure may be needed.

The only thing caveat is I don't like to run rear tire pressures lower than the fronts because of handling/braking/acceleration characteristics of tires. For example: if a rear left tire is low on tire pressure, it can roll more (which increases body rollover risk), but a driver might not realize this danger because the front with higher tire pressure is giving an increased handling threshold and feeling.
 
#6 ·
What tires?

My Bridgestones are XL rated (stiffer sidewalls for the higher weight) with the same size of 255/55R18 and I run ~36psi, take off-ramps like a teenager, and don't have excessive corner wear. Mine is also a 7 seater and I usually have extra weight in the boot, like my 50lb+ toolbox strapped at the very rear corner and extra full-size spare (kept the old 17in wheels).
 
#8 ·
235/60/18" last 13 years always 2,4 bar - 2,6 bar.
I dont know why every time I change from summer to winter tires or vcv.
tire service put me 2.7 bar and Im not driving anyone or heavy lugage.
Than I feel every small rocks or deviations like driving shopping basket on metal wheels.:)
 
#9 ·
I don't have a V8, but I run 42 psi front / 40 psi rear.

I prefer my front end feel to be a little stiffer and steering turn-in more responsive, understanding the trade-off is slightly less suppleness over bumps.

If I know I'll be traveling with a full load of passengers and luggage, as I was during the holidays, I air up 45 psi all around.
 
#12 ·
@ChitownV

I have stock suspension, 235/60R-18 Continental CrossContact LX20 which are XL

But I have been running this since day 1 with various tires, both XL and not, always stock size. I picked this up from the 2005 I had before the 07 (both new). FYI the 05 had it rated at 38 all around on door jam, where the identically equipped 07 had 36 on the door jam (and 38 in the manual for loaded car).

Volvo went down between 05 and 07 from 38 to 36 for some reason (softer ride maybe)? Change in regulation so you could have 2 pressures?
 
#13 ·
@ChitownV

I have stock suspension, 235/60R-18 Continental CrossContact LX20 which are XL

But I have been running this since day 1 with various tires, both XL and not, always stock size. I picked this up from the 2005 I had before the 07 (both new). FYI the 05 had it rated at 38 all around on door jam, where the identically equipped 07 had 36 on the door jam (and 38 in the manual for loaded car).

Volvo went down between 05 and 07 from 38 to 36 for some reason (softer ride maybe)? Change in regulation so you could have 2 pressures?
Great observations. Besides the change in the front alignment specs from toe-out to toe-in, this is good information of the "update" in vehicle specs. It's interesting because I would have also assumed the lower pressure is for the ride comfort. Then the "loaded" psi is only 38, not as high as 40.

Looking like for consensus, 36 is still okay, but if your ride comfort can handle 38+psi, then that may help with the outer tire shoulder wear if your specific XC90 is experiencing it.

For those wanting a conversion for Hong Kong's 2.4-2.6bar = ~35-38psi
 
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