i have 225/40/18 size tires and was wondering whats a good air pressure i should keep my tires on?......should their be more in the back than the front or equal all around?

thanks

 

What does the tire recommend? I keep 32-33 all the way around, and equal pressures.

 

the tires are toyo fz 4..........and the max pressure is 50

 

Max pressure is the maximum the tire can handle, and NOT the "recommended" pressure that you should be riding on. Didn't the tire dealer recommend it to you? If not, go and get yourself a small tanked air compressor. It's a worthwhile investment together with an Accutire air pressure gauge. Try an all-around pressure from 32-38 PSI then see what works for you. On winter 16's on stock Michelin Energy, I use 34 front and 32.5 rear and on my OEM 17's, it's 35 front and 33 rear. The stock 32 PSI all around is simply too lively for me. It all depends on your driving style.

Whatever you do, DON'T drive the car with the max 50 PSI on the tire.

 

on aftermarket low profile tires, the recommended tire pressure is 36-38psi. I have 225/45/18's and they recommended 36 all around. If you check your pressure after you drove it, it should be around 38-39, but checking psi on warmed up tires isn't recommended either. so to answer your question 36-38psi.

 

Always follow what's on the car... ie: 34psi front/32psi rear. the label on the tire is what the tire can handle.

 

Quote:

Originally Posted by goldendragon576

on aftermarket low profile tires, the recommended tire pressure is 36-38psi. I have 225/45/18's and they recommended 36 all around. If you check your pressure after you drove it, it should be around 38-39, but checking psi on warmed up tires isn't recommended either. so to answer your question 36-38psi.

One of the reasons why I got myself a portable compressor, so I can check my air once per week BEFORE I drive it off. Once I had a scheduled maintenance and they checked my tires. I guess they put it back to the factory PSI load, and the front of the TL looked flat. Plus, they put it back to 32 PSI WARM. So Cold was like 29 PSI. I freaked on them the following days as the tires had a higher scrub mark due to being underinflated. You have to remember that this is a front-heavy car (likely 60%F, 40%R) so the all-around pressure even when you just drive it by yourself still won't be right. My load is 50% of time alone and 50% with a wife and 2 kids, so 35F/ 33R seems to be my sweet spot, at least for these crappy Michelin OEMs.

 

Be carefull...this advice only applies to the stock tires it comes with. If you go with an aftermarket tire, then this definitely does NOT apply. Generally speaking, anything below 70% of max air pressure is considered UNDER INFLATED.

For the stock Michelins, 70% = 29 PSI. But...for my Sumitomo's 70% = 36 PSI. If you are that concerned about tire pressures, then you can always call the tire manufacturer and they'll tell you (I did...that's how I found out about the 70%).

Even with the stock tires, I always run @ 85% of max.