Technical > Automotive > Tire Pressure Charts

Tire Pressure Charts

Follow the recommended maximum pressure on the sidewalls, no chart needed.

A particular tire will be rated by it's construction, and purpose by the manufacturer.

reply to Loco
The sidewall rating is the max recommended. That doesn't mean you should use it. Use the ratings listed on the vehicle door jam or owner manual. There won't be any charts online, as tire construction, vehicle weight and use, and other variables will dictate the best pressure.

From his previous thread, it sounds like these are not stock sizes on the vehicle, Lurch.

Ok, didn't know. Here is a good article on the subject. It starts talking about this very subject about halfway down. There is a good rule of thumb from BFG in there too.
»www.modified.com/tech/0208scc_ti···dex.html

reply to Juggernaut

Sorry, but I have to disagree. Max pressures are at cold inflation.

so tires internal pressure doesn't increase from road friction, think about that for a second.

»en.wikipedia.org/wiki/Tire_code#Load_index

This is headed nowhere. Do some research, please.

if mfg spec is 30psi with an 86loadrating, and the tire is the same load-rating then 50psi is overinflated.

which will cause poor handling, void any warranties, as well as cause excess wear.

you should do some research.

Listed tire pressures are always listed for cold readings. The manufactures take pressure increases due to heat into account when they make their recommendations.

reply to Juggernaut

reply to Loco
Vehicles all have recommended tire pressure on the door sticker. I'd start there. It might even vary front to rear.

reply to Loco
Since it is not a stock tire, I would recommend inflating the tires to 90% of the maximum inflation pressure. If the maximum is 40PSI, fill to 36 PSI cold. If the ride quality or traction is objectionable, lower the pressure in 2 PSI increments (cold) until the ride seems better. Note that with a low profile sidewall, there isn't much flex available to help cushion the ride, so the vehicle will have harsh feedback which will only be exacerbated by higher pressures.

I would not recommend any pressure lower than 28 psi cold. Recognise that the tires and rims are subject to damage much more easily due to the low profile so it would be advisable to check pressure at least once a week.
--
"from a broken heart to a hole in the sky"

reply to Loco
First of all, the tire pressures on the car itself are for the OEM tires to have the most comfortable ride. They are not necessarily the ideal for tire longevity or performance, and they're completely out the window once you are no longer on the original tires.

I would run no less than 38 psi in the tires listed due to their short sidewall. Expansion after driving may make it 2-3 psi higher but it's not like it will rocket to 60 psi or anything.

The real issue will be keeping them at proper inflation. By they time they "look" low they'll be very low, so checking at a regular interval is a must.
--
John M - Cranky network guy

reply to Loco
Been busy with calculating tire-pressure, with use of the calculation I got hold of , that is used in Europe for decades and also in America since 2006.
But also found out that it can be better, especially for low aspect-ratio tires like here used ( 245/35/ZR20, here the 35) . You have to calculate better with the maximum presssure and not the reference-pressure, as it is called and is 35 psi for standard-load tires in America. But then even , if the tires have a big reserve- load , the advice-pressure can be lower.
I will try to give a link here to my public map of skydrive/hotmail, where you can load several spreadsheets to calculate the new pressures for non OEM tires.

[mod note: link removed]

if this does not show as a link , copy and paste it in the adress-line of the browser.
If you cant work it out, let me know, and give me the needed details.
This forum has no registration, and I selected the email-replie, so see if it works.

jadatis,

Welcome and thanks for helping out. Due to an abundance of caution, I took out the link. If you could post a screen shot of a chart, that would be appreciated.

There's a potential risk from a repository of untrusted files. Too much zero-day entertainment floating around the web to take chances.

Again, thanks.
--
When diet and exercise just aren't enough, there's Ipecac.

reply to Loco
Are those wider than the stock tires? If yes, and not by much, you can use the recommended pressure from the door sticker or manual.

You can google for the "chalk method" and use that to determine the optimal pressure. One issue with overinflated tires is that the contact patch will decrease, and that can cause problems on wet roads.
--
Wacky Races 2012!

I wouldn't put in more than the recommended pressure for your vehicle, however much that may be.
--
Wacky Races 2012!