Tire Pressure - Page 2

JDookie · 04-04-05, 05:27

Quote:

Originally posted by bet993
Not to pick on JDookie but 35psi is not a good round number to just throw out to the general public. 35 psi on the 18” rear wheels, of my rear engined 996 would result in rim damage and/or tire damage on all but the sedatest driving and/or on the smoothest roads. The factory recommendations for the rear tires on my car are 44 psi (fronts are 36psi).

Don't worry, everyone is entitled to their opinion and I don't take anything personal in open discussions as this, but I would like to comment on your view.

35psi is my rule of thumb as a *minimum* amount of air pressure in a *passenger car*. If you re-read my previous statements, you will see that I used the word minimum because I feel anything under 35psi is just too low. I wouldn't consider you car a *passenger* car even though it does in fact carry a passenger or two.

Now, as far as your car's rear tire pressure, I'm sure Porsche doesn't expect you to only drive in straight lines under 35mph to the grocery with a 996, so they are giving you a tire pressure that is compatible with any type of driving style you may have, regardless of whether that means your grandmother driving your car at 30mph or you racing your car at the local SCCA meet, so 44psi in your rear tires is meant to cover all bases.

I'm not saying you should lower your tire pressure by any means, I voted for following the manufacturer's specifications and follow those specifications to the "T" when checking my tire pressures, but to say that you *can't* drive your car with 35psi in your rear tires is untrue. Of course you can. I have 22" wheels with very wide and low profile tires and only run 35psi all the way around, and I'm positive my vehicle is heavier than yours and am not in any danger of damaging my wheels.

To the general public, I say to always follow the manufacturer's specifications, but sometimes a little *adjustment* of your tire pressure isn't a bad thing.

hirosh · 04-04-05, 05:49

Quote:

Originally posted by HRP
As mentioned above: Taylor your pressure (within the specs of the tire) to the specific application and your preference in ride and handling.

yup. no more than 44 psi, but more than Ford's recommendation on my mustang. i guess because i like the stiffer feeling a higher psi gives. anything under 40 psi feels like the sidewalls are folding over or something.

JDookie · 04-04-05, 05:52

Quote:

Originally posted by hirosh
yup. no more than 44 psi, but more than Ford's recommendation on my mustang. i guess because i like the stiffer feeling a higher psi gives. anything under 40 psi feels like the sidewalls are folding over or something.

Try driving on 28" ET Drags with only 12psi in them!

SergC · 04-04-05, 08:00

Quote:

Originally posted by kartoon
I only follow the vehicle manufacturer's recommendations.

The tire manufacturer does not know the kind of vehicle, load and other factors. They usually specify optimum or maximum tire pressure.

Same here.

bet993 · 04-04-05, 09:16

Quote:

Originally posted by JDookie
I'm not saying you should lower your tire pressure by any means, I voted for following the manufacturer's specifications and follow those specifications to the "T" when checking my tire pressures, but to say that you *can't* drive your car with 35psi in your rear tires is untrue. Of course you can. I have 22" wheels with very wide and low profile tires and only run 35psi all the way around, and I'm positive my vehicle is heavier than yours and am not in any danger of damaging my wheels.

To the general public, I say to always follow the manufacturer's specifications, but sometimes a little *adjustment* of your tire pressure isn't a bad thing.

It is interesting that you say that because I actually do not follow the factory recommendations. I run slightly lower pressures than the factory recommends for my car (34/39 which is closer to the GT3 specs.). It has helped to dial out a little of the understeer.

I will say that while messing around with tire pressures on my old 993 I managed to crack a rear wheel at some point. The turbo twist I had were notorious for bending and/or cracking, so I am not sure whether it was the tire pressure or the pavement/wheel that was the problem).

I guess my biggest concern for making broad general statements about significant items such as tire pressures is that it could mislead the uninformed. I like to make disclaimers when making such statements (guess it comes from my job). I honestly don't know whether 35 psi is appropriate for the majority of passenger cars or not. I know that my wifes car has a factory recommendation of 32/36 for general purpose use.

HRP · 04-05-05, 07:43

Thought this link discussing tire pressure by people from driving schools would be of interest:
http://www.drivers.com/discussions/m...6440184#POST41

O4cobra · 04-05-05, 08:00

As JDookie said the problem with the Explorer was the tires and being underinflated. Ford actually said to run them at 26 all the way around, way to low. But if you think about, all of the problems they had, how many people do you think really ran the tires at 26, so I think it was a Firestone problem more than anything!

As far as pressure, no tire has a recommended tire pressure. You will never find a tire with a recommended pressure on it, street tire that is. As some others have said the tire manufacturer has no idea what vehicle the tire will come on. For instance, I work for Goodyear company owned store. We sell the RunFlat tires for the Vettes, that is the only vehicle we can put those tires on. And the tire only has a MAX pressure, not a rec. pressure. So even knowing what vehicle they will go on, they still will not give a recommendation on the PSI. Always go by what the vehicle manufacturer says, within reason. The general rule of thumb I give my customers is if you want a lot of air in the tires, go a couple of pounds below the max, I try to never put the max in the tire just to be safe. If it says 44, go 40 or 42. If it says 35 go 33. Tires are not a part of the car to take lightly or to overlook.

Guess My Name · 05-06-05, 09:10

Never seen where a tire manufacturer recommended tire pressure for my truck....

So I start with the door jam sticker and work from there..

jasonmac · 05-11-05, 06:08

Vehicle manufacturers, though it depends slightly on if summers or winters are on.

rjstaaf · 05-11-05, 06:35

Quote:

Originally posted by hirosh
yup. no more than 44 psi, but more than Ford's recommendation on my mustang. i guess because i like the stiffer feeling a higher psi gives. anything under 40 psi feels like the sidewalls are folding over or something.

Reid,

What tires are you running on your Mach1? Are you still on the stock Goodyears? If so, ditch them as soon as possible

rjstaaf · 05-11-05, 06:38

I run 35 all the way around on my GT with BFGoodrich KDW tires. If I recall, the sticker in the glove box says 30 front and back. The KDWs have a very stiff sidewall and are very different than the stock Goodyear Gatorbacks. Here is a case where you have to use your own judgement and monitor your tire wear adjusting pressure as necessary. Initially following the manufacturer's recommendation with these tires I noticed excessive wear on the edges. The balance and alignment were perfect so I bumped the pressure up to 35 lbs and with regular rotations and constant monitoring the tread wear has been perfect ever since.

The manufacturer's recommendations are based on a certain tire so what works for one tire may not work if you replace your tires with a different type.

JasonC8301 · 05-11-05, 07:19

I follow the manufacturer's recs. on the doorjamb. 30 psi all around.

After checking my tire pressure every 1000 miles (got 4K so far), tread seems normal. Even with a little spirited driving, tread wear is normal (sometimes I take corners a bit too fast and use the abs a little.)