Confused by proper tire pressures

The plate on the door panel of my 2004 Forester recommends tire pressures of 29 (front) 28 (back) with a light load and 29 (F) and 36 (B) with a full load. Yet I notice that, when mechanics service my car, they usually put 32 lbs in all 4 tires. I am driving tomorrow on the Interstate over the mountains from Olympia, WA, down to Oakland, CA, with my son and our luggage. The I-5 could be slick. We will be carrying chains just in case. I left the front tires at 32 and inflated the back tires to 34. Does that sound about right? Somehow 29 seems low. And I read somewhere that underinflated tires are bad for the suspension and tires. Thanks for any advice.

Reply to
tenplay
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I think your sense of this is pretty good. Generally, I add 5-10% to the recommended pressures, for 'normal' daily driving, for 2 reasons, the car handles better and the pressure is sometimes a little low (often just one odd tire???) the next time I check pressures - so the wear probably averages out. And I always add a little more pressure for extended highway travel with luggage and/or passengers - I suppose it helps reduce heat in the tires as well as distribute wear and help with handling. Oh, but you should never use more pressure than that listed on the sidewall as 'max' and pressures should ideally be tested on a 'cold' tire.

Carl

Reply to
Carl 1 Lucky Texan

Your mechanic is an idiot.

Inflate the tires to factory specifications when they are at the proper ambient temperature.

Reply to
Oscar_Lives

Reply to
davesixtythree

You're carrying a basic emergency kit too, right?

Enjoy the trip, I wish our trips were as scenic here in the midwest.

-John O

Reply to
JohnO

I just checked my '03 Forester's yesterday and put in 30 psi all around. Funny thing was when I got car and had over 3,000 miles on it, I discovered tires were all 40 psi. I had taken to dealer for first time oil change and complained and had him set to standard. Dealer claimed that care were shipped at higher pressure to avoid having to reinflate standing in lots. Ride is smoother at lower pressure but the high pressure excursion did not harm tires and my mileage was up.

Probably a good idea to set pressure a little above specs since tires are going to lose air anyway.

Frank

Reply to
Frank

Don't know if I'd put it that way but the mechanic doesn't know how to properly inflate tires.

How much pressure you should run depend upon how much load they are carrying. Lightly loaded the front of your car will be the heavier end and should have higher pressure than the rear. As car is loaded a larger % of the load is carried by the rear of the car and ratio of front to rear pressure will change.

What you need to do is weigh your car, each axle separately and weigh with load that is typ for everyday driving. Next weigh the car loaded as closely as you can to represent how it will be loaded on your trip. Next refer to a load inflation chart for your tires and inflate according to the weight the tires will be carrying.

If for some reason you won't or can't do it the proper way, use the chart on the car.

Mickey

Reply to
Mickey

I found 32 all around to be a good compromise, at least on an Outback. Generally you like to have the fronts a little higher than the rears because of the engine/transmission weight. About the best I've found is 34 front and 32 rear.

Reply to
Jim Stewart

Mickey wrote: pressure will change.

My wife refuses to let me know her weight. Is it safe to drive her around in my Forester or should she drive separately? Frank

Reply to
Frank
32 all around works for me

snipped-for-privacy@yahoo.com wrote:

Reply to
bigjim

Reply to
Trlather

Your 32/34 is what I run mine at when I expect to be loaded and 32/30 normally.

Reply to
Edward Hayes

In that case she needs to walk!

Reply to
Spam away

She doesn't weigh that much. I can tell by her favorite: "reverse cowgirl" that she isn't much over 125 lbs.

She might want to get that little mole looked at, however...

Merry Christmas!

Reply to
Oscar_Lives

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