Hey folks, I just picked up a set of 18's and was wondering what the correct tire pressure should be or how I could find out the correct tire pressure since the wheels are no longer stock? Here is a link on the rims I got...
http://cgi.ebay.com/ebaymotors/ws/e...TRK%3AMEWA%3AIT

 

look on the sidewall of the tire, the max psi will be listed there. I usually run about 10 psi less than that. I don't know if there is some rule of thumb but I normally run between 32-36 psi.

 

Is there any surefire way of finding out exactly what the pressure should be or do most people do what you do?

 

No, I don't believe that there is just one tire pressure value to use. It depends on what your preferences.

See posts by Maxart in the thread below for some good info:

http://forums.maxima.org/showthread.php?t=390383

 

I am still running the 15" sawblades and recently bought a set of Yokohama Avid H4S all-season tires. The placard calls for 33F/32R. I started inflating my tires more about six months ago and am presently experimenting with 35F/34R.

I think anything less than 32 lbs. is probably too low for optimum fuel economy, tread wear, and perhaps handling for a Maxima.

 

I spoke to someone from Tire Rack about this. He states that as long as the tire size is correct, (meaning for that for a 18 in wheel it should be a 235/40 tire), the amount of airpressure should be the same as stock. Maybe a pound or two higher for performance.

 

It says on the side of the tire the range of pressures that should be run... like someone else previously said...

 

I know that the side says a range, but it's usually a large range and I would like to know specifiaclly within +-5 psi what the pressure should be. I will probably experiment but will put about 35 psi in the tires to start with and see what happens after awhile, thanks for all of your help!!

 

You should be good to go with 35psi. You might want to put one lb. more in the front tires than what you put in the rear.

 

There is a way to determine optimal pressure, what you do is, you take a chalk and draw a line on the tire starting from the middle of the sidewall and across the whole thread (from left to right). After that go out on an empty parking lot and make a couple of fast turns - when your tires start making a slight noise (don’t abuse them though, don’t make them scream)

So after a couple of left and right turns if some chalk is left on the thread near the sidewall, you are overinflated, if some chalk is erased from the sidewall, you are underinflated. For a little more comfortable everyday ride drop 2 -3 psi

 

that's a fine idea...thanks!

 

I've had the 235/40-WR18 setup since 2k2, and do a 35 F / 32 R . Pretty disgusting to put more in the front than rear, huh? But that's FWD for you. I will also admit that my 1st set of 18's seem to have prematurely worn out, possibly due to overinflation (wore out in the center not the edges), so more is not better.

 

What kind of tires were these? 35 psi should not have caused premature wear. Did you ever rotate the tires? How often did you check tire pressure and re-inflate the tires?

 

i was told to use the stock pressure give or take for your personal needs. i use less air for better traction

 

I run 40lbs in my Toyo Proxes 4's just like I did in my Toyo Proxes T1s's (245/40/18).

If I recall correctly the recommended inflation pressure changed based on how fast you planned on driving on them.

 

Frank,

Actually, when they wear out in the center, it is due to under-inflation. The centrifugal force pulls the center of the tire out if there isn't enough air in it.

 

I believe it's the opposite--when a tire is over-inflated, it rides on the center of the tread. When it is under-inflated, it rides on the outsides of the treads and the center makes little contact.

My Sumitomo HTR+'s lasted 29k, and that's sad for an all-season 18. My Kumho's already have about 21k and they look like they haven't seen any wear yet. Sometimes you can take all the advice from the Tire Rack and their surveys and throw it in the garbage (Sumitomos got mucho positive reviews). The data is not statistically valid or reliable, it's totally subjective. You wouldn't want the Tire Rack running clinical trials on new drugs, trust me. And I doubt there are statisticians backing up what they collect. You have to put the tires on the car yourself and observe the results.

The new car will have run-flats, with a 50/50 rule on driving with flats. I have no clue how that changes the equation because I've never previously had them before.

Clue
Culprit
Remedy

Both edges worn
Underinflation
Add more air; check for leaks

Center treads worn
Overinflation
Let air out to manufacturer's specifications

One-sided wear
Poor alignment
Have wheels aligned

Treads worn unevenly, with bald spots, cups, or scallops
Wheel imbalance and/or poor alignment
Have wheels balanced and aligned

Erratically spaced bald spots
Wheel imbalance or worn shocks
Have wheels balanced or replace shocks

Edges of front tires only worn
Taking curves too fast
Slow down!

Saw-toothed wearpattern
Poor alignment
Have wheels aligned

Whining, thumping, and other weird noises
Poor alignment, worn tires or shocks
Have wheels aligned or buy new tires or shocks

Squealing on curves
Poor alignment or underinflation
Check wear on treads and act accordingly

 

It can really go both ways. Low profile, wide tires (I assumed you had a wide tire) act differently than passenger tires and low pressure can be the culprit. Most, if not all, literature you will find was written way before a 40 or 50 series tire existed. I'm going off personal experience. Results will vary. The moral of the story is, "Set the pressure to Manufacturers specifications."

 

I agree with you on the pressure advice. But where I especially agree with the mfg. is the balance between F/R--if the mfg says 31/29, I doubt anyone should go 32/32, or 32/35, etc. Maybe 35/32, but stick F > R.

My g/f's CR-V says 26/26--we went out on a limb and bumped it to 30/30, but kept the F/R equal.

There seems to be a misconception that bigger rim = higher pressure, or one should read the sidewall to find out what to put in. Both of those are wrong.

When I originally got my 18's, I had a flat repaired at a so-called high performance shop, you know, the 10k Hunter balance machines, stick-on weights, etc. Yet the technician told me to inflate my 235/40-18's to 48 lbs, I was like say what?

I continue to use 35/32, don't see any detriment to my Ecsta A/S which I think are a good tire. Why my Sumitomo's lasted 29k with proper balance, alignment, and 35/32 I'll never know....

 

http://www.toyojapan.com/tires/pdf/TTT_17.pdf

http://www.tirerack.com/tires/tirete....jsp?techid=72