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Tyre pressures

Posted: Thu Oct 02, 2003 7:14 pm
by DOA
Hey peeps, new to the forum and just got a legacy turbo in the UK. Some good stuff on here and youve already answered a few of my questions without knowing it :o .
However Ive not got any idea what tyre pressures I should be running (good to check just in case). Ive got Impreza 16" wheels on with 205/55 tyres on instead of the standard wheels and Im wondering if anyone knows what pressure the standard legacy tyres should be at and if anyone knows what the Impreza pressures should be.
Any help is gratefully received :D .

Posted: Thu Oct 02, 2003 7:17 pm
by Legacy777
Tire pressure is completely relative.....

It will vary for individual, driving tastes, roads, etc.

I will usually use what the manufacture states for the car, and what's on the tire for max pressure, and use something in between.

For example, my goodyear gs-d3's have a max pressure of like 44 psi or something, but they perform best around 30 psi.

Unfortunately, there's no clear cut answer to your question.

BTW, welcome to the board.

Posted: Thu Oct 02, 2003 7:21 pm
by DOA
LOL, I know theyre subjective (and I normally leave the front pressures and up the rears a fair bit) but im after the manufacturers pressures as a starting point, tends to give good grip and fuel economy.

Posted: Thu Oct 02, 2003 7:32 pm
by vrg3
Josh is right that it will vary a lot. It depends most on the car's weight and weight distribution.

The marking on the sidewall of the tire is almost always irrelevant! All that number tells you is how much pressure it takes to make the tire explode. You should never go above it, but you will likely never get close to it anyway.

The place to start is Subaru's recommendation on your door jamb. As long as the tire width doesn't change, that recommendation won't change.

If you use wider tires, you sometimes will want to decrease tire pressure a little because the contact patch will increase in size. Likewise, narrower tires often call for higher pressures. This isn't a hard-and-fast rule, however; it kind of depends on how much it changes.

So I'd suggest starting with what's on the door jamb (something like 34psi front/32psi rear I think) and then adjusting from there. On my car (also a Legacy Turbo with 205/55R16 tires) I found I liked it best with roughly 36psi in front and 35psi in the rear.

Posted: Fri Oct 03, 2003 8:06 pm
by evolutionmovement
The tire won't explode quickly at the side wall's pressure, but I'm not recommending going that high. Was driving through the desert in the summer cruising at about 100 and the car started slamming over bumps. It took me several miles to figure out what was going on and when I finally pulled over and checked the pressure, I found it was over 50psi (the dial only went to 50 and it was pegged. the tires had a 44psi limit). Lucky day I guess. :shock:

Steve

Posted: Fri Oct 03, 2003 10:44 pm
by DOA
Erm, jolly good, I wasnt worried about anything other than the manufacturers specs lol. Im not worried about overpressuring em as i just wouldnt, but thanx, Ill double check the doors out and go from the 34-32.