Read my posts and links in the thread that Jonathan Woodall linked.
The only authoritative tire pressure recommendations developed by engineering professionals who are in a position to know all the pertinent facts are the ones provided by vehicle manufacturers.
It’s not out of the question that recommendations derived from real-world experience could be suitable, but there will generally be only anecdotal evidence – or no evidence – to support them.
The pressure listed on the tire sidewall is a maximum pressure for the tire – do not exceed it.
The maximum pressure listed on the tire sidewall is NOT proffered as a RECOMMENDED pressure. Tire manufactures do NOT claim it is a recommended pressure. Vehicle manufacturers do NOT claim it is a recommended pressure. Sorry, but only people who don’t know what they’re talking about think it is a recommended pressure.
Use the pressure recommended by the vehicle manufacturer.
Have you ever seen a tire with a recommended pressure written on it anywhere? I sure haven’t. What is written on the sidewall is the maximum pressure rating.
Recommended pressure is defined by the car manufacturer.
Inflating the tires to their maximum pressure will probably result in the center of the tread wearing out prematurely over the long term, and flirts with their safety limits. Going above max can result in them blowing out.
I’m puzzled by this. Wasn’t the big brouhaha between Ford and Firestone over the Explorer and its tires caused by the vehicle manufacturer calling for what the tire manufacturer insisted was a pressure that was too low?
I’ve never seen a “recommended” pressure on a sidewall, but I have seen literature that gave “recommended” pressures which came from the manufacturer and automaker. My “offical” FIAT factory service manual (North American edition) had an insert which gave recommended pressures for a few makes of Pirelli tires and their pressures, which was from Pirelli. I’d say this is very unusual.
Yes. Most everyone except Ford would judge that the recommended pressure was too low. I agree, and believe that Ford screwed up, ignoring safety for the sake of a smoother ride.
Nevertheless, it’s still only the vehicle manufacturers that state recommend pressures. Tire manufacturers know enough about the subject to recognize when the car maker’s recommendation seem to be inappropriate, but it’s up to the car maker to set a recommended pressure.
The pressures are vehicle-specific (e.g., all '95 Camrys call for x psi), not tire-specific. A given model of tire may well be expected to run at x psi on one model car, and y psi on some other model. That’s fine so long as x & y don’t exceed the maximum determined by the tire manufacturer, and so long as the car engineers come up with a suitable pressure. The Ford/Explorer fiasco is the only case I’m aware of where it seems that latter condition was not met.
Since people are getting all testy about a few pounds here and there,
I’d like to say a few words about the accuracy of your typical tire gauge.
They’re terrible.
Especially the ones that are ‘built in’ to the fuel station hose. Honestly, there can be really laughably hig and/or scarily low. The ‘piston’ type ones are shameful as well.
I hear this all the time. However, when I went out and checked my two “pencil”-type gauges against a higher-quality dial-type, I was quite surprised at the agreement. Repeatability was not bad, either. I’d certainly trust them to within 1 psi or so. (I totally agree that the built-in gauges on the air hoses are worse than useless.)
That said, I use the dial-type one when I set my tire pressures (to the values recommended on the door placards! ).
Adding to what Gary T said: Pressure recommendations often differ from front to rear on the same vehicle, which uses four identical tires & wheels (e.g., my 2000 Honda Civic: 30 psi front; 29 psi rear).
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