Infiniti recommends 18 psi below the max tire pressure?

[TooMuchGlass]

7: gotcha. That's what I figured, but i'd rather know than figure. Thanks.

[TooMuchGlass]

the car has about half a tank now, I think I'll keep the tires where they are for now and then fill them up to a peppy 51 with my next $80 of gas. We'll see just what kind of difference it makes!

[redpoint5]

Road noise was much more pronounced when I went from 32psi to 43psi on my TSX. Handling also improved, but the ride was more harsh.

I wish the center would wear out faster on my tires, but steel belted don't bulge much. No matter what, I always wear the outside edges first. Increasing inflation pressure should make my tires last longer.

[ecomodded]

I think a lot of people confuse tire types,as the nitrogen installer did.
The old bias ply tires from days gone bye would indeed wear out the center first if over inflated.
The new stronger wider steel belted radial tires are usually rated somewhere around 42 lbs to 50 lbs max pressure.
Often the front tires will have bald edges,if excessive it is due to worn/ loose suspension parts.
My tires also get louder with higher air pressure, i keep them at 50.

[slowmover]

Stay inside the vehicle manufacturer specifications for tire pressures. Ever since the Ford Explorer / Firestone fiasco of a decade ago the testing of tires, the determination of pressures-versus-loads, etc, by the automakers has made them serious about the relation of tires and suspension in handling dynamics.

Better ride quality? Yes, but to stray outside the parameters (in reading tire engineer CapriRacer's website Barry's Tire Tech) is to invite "unexpected problems" in certain situations (my reading and word choice).

Longest tire life -- [1]] given the expense of premium tires; and, [2] the absolute centrality to safe road performance of predictable vehicle dynamics based on the interplay of tires & suspension -- is worth more on several fronts than the small mpg gains of "over" inflation.

That said, a few pounds to the good isn't seen as detrimental. Where that point lays needs some experimentation (load versus pressure as in per wheel scale weights for a given loading of the vehicle).

If one knows the best pressure for solo commuting . . and knows what it is for full passenger and cargo load at highway speeds in high heat, one probably knows the percentage change (not number absolute) as well. This is worth finding, IMO.

[AeroModder]

45 is a good balance for me. Not overly harsh, but still rolls well.

[niky]

The manufacturer sometimes gets it wrong. Older models have door stickers that suggest 26-28 psi... Where modern data suggests that pressures between 30-35 psi are best for preventing heat build up and hydroplaning.

The door sticker minimum is there to suggest what pressure is most comfortable. Look at the maximum load pressure on the door sticker to see what the manufacturer thinks you should actually run.

Running pressures higher than the manufacturer suggests on the door sticker maximum load recommendation will have a negative effect on vehicle dynamics. Usually a harsher ride, and possibly a tire that bounces a lot on rough roads, as the shocks can't control it as well as a softer one, but by and large, it is safe. Safer that softer tires. Better at evacuating rain water. Grippier in the dry because there's more pressure on the contact patch. Conversely, when we go off-road, we air down our tires because we want less pressure on the contact patch, so the tires won't sink as far into the mud... But the pressures we use there would be DANGEROUS on the highway!

I've actually seen center rib wear at high pressures on some extra wide low profile tires, but most ordinary tires will see no extra center wear at 40-45 psi.

[ecomodded]

Originally Posted by slowmover

Stay inside the vehicle manufacturer specifications for tire pressures. Ever since the Ford Explorer / Firestone fiasco of a decade ago the testing of tires, the determination of pressures-versus-loads, etc, by the automakers has made them serious about the relation of tires and suspension in handling dynamics.

If i remember correctly the ford/firestone highway roll over issue was due to low pressure not high pressure.
Low pressure will also cause your tire to roll off the rim on corners.
Never drive with under inflated tires, My advice is to put them 5 psi over at the gas station as they are warm and sidewall rating is for a cold tire.

[redpoint5]

Originally Posted by ecomodded

Often the front tires will have bald edges,if excessive it is due to worn/ loose suspension parts.

The edges wear out on mine because I don't use my brakes, especially for cornering. Straight speed isn't fun for me, but I do like to go through a turn quickly.

Originally Posted by slowmover

Longest tire life -- [1]] given the expense of premium tires; and, [2] the absolute centrality to safe road performance of predictable vehicle dynamics based on the interplay of tires & suspension -- is worth more on several fronts than the small mpg gains of "over" inflation.

Has it been shown that over-inflation has a negative impact on tire life? I believe the opposite is true, up to a certain amount of pressure. I hear what you are saying on point 2 also, but everything in life is a compromise. What may be within a comfortable safety margin for one person might be outside of that safety margin for another.

My advice is to try various pressures and see how it handles, sounds, and consumes fuel. Finding the balance of these things is up to the individual.

[some_other_dave]

Originally Posted by Sven7

... autocrossers and circuit racers pump em up to reduce sidewall roll (when the tires tuck under a bit during cornering, as below) and improve handling.

Depends on the tire. For instance, many of the dedicated track tires grip better with lower pressures. (It used to be "most"; I'm not sure about now.) Most of the actual street tires grip better with higher pressures.

There are exceptions in each, of course, which is why testing is important.


Like redpoint5, I don't like to slow down for corners. So far, I have worn out two sets of tires at "high" pressures, and neither set had significantly more wear in the center of the tread than at the edges.

-soD