Shop overinflated my tires. What do I do?

[Dubzino]

Can you guys please help me out with this one. I have 225/35/20 tires on a 2001 Infiniti I30 and where I got them put on they over inflated my tires to 50psi. I am lucky a friend noticed that they looked over inflated. I had been driving on them for a few weeks. I was told whoever did this was trying to mess up my tire tread wear. So what should I be setting my tires presure at normally? Stock specs? 34 psi I think it is?

[audtatious]

I will say on the sidewall what the maximum inflation should be.

[cullenj76]

Can you guys please help me out with this one. I have 225/35/20 tires on a 2001 Infiniti I30 and where I got them put on they over inflated my tires to 50psi. I am lucky a friend noticed that they looked over inflated. I had been driving on them for a few weeks. I was told whoever did this was trying to mess up my tire tread wear. So what should I be setting my tires presure at normally? Stock specs? 34 psi I think it is?

34 is the suggested pressure for OEM tires, not the 225/35 tires you have now. You should generally inflate them to 80% of the max pressure stated on the tire and under/over-inflate from there to suit your preferences.

Make sure you are measuring the tires when they are cold. They might have inflated them when they were cold, and then they were checked by you when they were hot. I doubt they were really trying to mess up your treadwear, because if they wanted to to that they would have under-inflated them. Almost all tires wear prematurely/uneven due to under inflation which caused the outside/inside edges of the tire to wear and not over-inflation which causes wear on the middle tread ribbons.

[Dubzino]

Yea that

I will say on the sidewall what the maximum inflation should be.

Yea thats where I am kind of confused. At one part of the tire it says 40 psi and another part it says 50 psi. So what should I fill them at? ANy help would be great.

[AZhitman]

I doubt it has 2 numbers - Read the sidewall carefully, jot down the wording, and report back.

50psi won't hurt a thing.

What's the load rating on those tires (you can look it up on TireRack.com)?

If it's too low for the car, then the shop may have done you a favor. Higher air pressure will grant a small margin of additional load rating, but is no substitute for properly-rated tires.

225/35/20? Gotta be NO sidewall on those...

[Dubzino]

I doubt it has 2 numbers - Read the sidewall carefully, jot down the wording, and report back.

50psi won't hurt a thing.

What's the load rating on those tires (you can look it up on TireRack.com)?

If it's too low for the car, then the shop may have done you a favor. Higher air pressure will grant a small margin of additional load rating, but is no substitute for properly-rated tires.

225/35/20? Gotta be NO sidewall on those...

Yea you are right. Sidewall is next to none. If I turn my steering wheel all the way to one side the rims look liek they are sitting on the ground. But anyways I did what you said and took a closer look today. The 40psi is the max for seating the beads and 50 psi is the max tire presure. So then I should go 75% of 50 psi correct?

[AZhitman]

I'd run them at 50. You don't live in an area that's hot enough to cause much expansion, plus you'll pick up a little more sidewall strength.

If you wanted to get real technical, on a RWD heavy car, I'd go 50 F and 45 R.

[MaximA32]

Greg, I hate to do it but, considering I work for a tire company I have to step in and say something. The manufacturer puts the inflation on the tire placard for a reason. The pressure the mfg reccomends is for the best gas mileage and for the best handling for the vehicle. Now, the tire placard on Nissan/Infiniti vehicles is generally located either somewhere on the drivers door frame or on the door itself. There are a few more locations that it could possibly be and if its not on the door then get back to me and I'll be happy to tell you the other possible locations.

Now, as for proper inflation. They don't generally change the reccomended pressures all the time, the pressure for that vehicle SHOULD be 29 psi for the front tires and 32 psi for the rear. Although, the tire placard will tell you at what pressure the mfg recomends. It doesn't matter if it's not the OEM tire size or not, the mfg puts that air pressure there for a reason.

[NSR_s30]

...Also with that small of a sidewall it can't hurt to run more air, as the wheel has less to protect it with such a small sidewall and also from hitting say a pothole and cracking the wheel. In wheels like those, I'd suggest running 35-40 psi although you'll give up your handling cause you already have much bigger wheel on there, which will cut short the braking ability of the vehicle with such a bigger mass to slow down. In any case, your tires should be fine, driving on them for a couple weeks like that probably didn't cause any weird edgewear. Just put the pressure at what you want them at, if you want a stiffer ride, have a little more air in them, if you want softer let some of the air out, but like I said with those wheels I'd run 35-40 psi.

[MaximA32]

I concur.

[Dubzino]

Thank guys. Whenever I have an issue or something I am unsure about. You guys are right there to help me along the way.Thanks again guys for all your help.

[audtatious]

...Also with that small of a sidewall it can't hurt to run more air, as the wheel has less to protect it with such a small sidewall and also from hitting say a pothole and cracking the wheel. In wheels like those, I'd suggest running 35-40 psi although you'll give up your handling cause you already have much bigger wheel on there, which will cut short the braking ability of the vehicle with such a bigger mass to slow down. In any case, your tires should be fine, driving on them for a couple weeks like that probably didn't cause any weird edgewear. Just put the pressure at what you want them at, if you want a stiffer ride, have a little more air in them, if you want softer let some of the air out, but like I said with those wheels I'd run 35-40 psi.

Driving "over-inflated" won't cause edgewear, it will cause the center to wear more quickly. Driving under-inflated will cause edgewear because the center section will "cup" and there is more rollover during turns.

[NSR_s30]

[0wn3r]

Greg, I hate to do it but, considering I work for a tire company I have to step in and say something. The manufacturer puts the inflation on the tire placard for a reason. The pressure the mfg reccomends is for the best gas mileage and for the best handling for the vehicle. Now, the tire placard on Nissan/Infiniti vehicles is generally located either somewhere on the drivers door frame or on the door itself. There are a few more locations that it could possibly be and if its not on the door then get back to me and I'll be happy to tell you the other possible locations.

Now, as for proper inflation. They don't generally change the reccomended pressures all the time, the pressure for that vehicle SHOULD be 29 psi for the front tires and 32 psi for the rear. Although, the tire placard will tell you at what pressure the mfg recomends. It doesn't matter if it's not the OEM tire size or not, the mfg puts that air pressure there for a reason.

I disagree.

OK, i suppose you'll want reasons...

For one, you're telling him to look at the placard which would list information for a stock vehicle. Correct me if I'm wrong here, but those wheels don't exactly look stock anymore. My point is, I think unless you're going with OEM tires, you should stick relatively close to what the tire manufacturer recommends. From there, read that word "MAXIMUM" tire pressure and then follow the advice.

Unless you've really heated up your tires, I'd just say let some of the air out and be done w/ it...

[Sentientbydesign]

Different tires are going to require different pressures.

My experience has been as follows. Stock setup- 32psi up front/ 29-32 in the rear (less handles a little better under extreme conditions)

17" Motegi MR7s with Dunlop FM901s tire shop inflated them to mfg recommendation and they looked low and they handled nasty. So I inflated them to 40/38. Much better handling and response.

They're your tires, learn how you like them within safe bounds.

[audtatious]

I know for a fact that running Simitomo 235-40's with low pressure caused a blowout at 80mph. I keep my Yoko 235-40's at 38-40psi.

[Beancooker]

Greg, I hate to do it but, considering I work for a tire company I have to step in and say something. The manufacturer puts the inflation on the tire placard for a reason. The pressure the mfg reccomends is for the best gas mileage and for the best handling for the vehicle. Now, the tire placard on Nissan/Infiniti vehicles is generally located either somewhere on the drivers door frame or on the door itself. There are a few more locations that it could possibly be and if its not on the door then get back to me and I'll be happy to tell you the other possible locations.

Now, as for proper inflation. They don't generally change the reccomended pressures all the time, the pressure for that vehicle SHOULD be 29 psi for the front tires and 32 psi for the rear. Although, the tire placard will tell you at what pressure the mfg recomends. It doesn't matter if it's not the OEM tire size or not, the mfg puts that air pressure there for a reason.

REmember the Ford Explorer/Firestoine problem. Ford says 25psi, Firestone says 40psi. At 25 psi you'ld blow out the tire. At 40 psi the vehicle would want to roll. The Manufacturers placard is only good for OEM tires and wheels. And if it's a Ford, question it!