Tire Pressure Question

[hans030390]

I'm trying to find the optimal tire pressure for my car/tires. I'm driving a 2011 Fusion SE with Hankook Ventus V2 Concept tires (225/50R17/94V). When I got the car last week, they were all at 40psi. The sticker in my car says all tires should be 31psi, so I lowered the pressure to about 33psi on all tires.

I'm asking because I'm not sure if the recommended pressure would change based on different types of tires. I think these are somewhat low-profile tires. I've done some research on the recommended pressure, and I'm getting very mixed results. Some say to still follow what the manufacturer recommends. Some say these types of tires, or even just lower-profile tires in general, require a hire pressure than that. So, basically, I'm seeing varied reports of setting them anywhere between 30-45psi (45psi seems extreme given the max 51psi listed on the sidewall).

I'd appreciate any insights you might have on the matter! And for anyone that saw my post a month or two back, I ended up going with a Fusion because I got a great deal on a used fleet car. Loving it so far!

 

[satyajitmenon]

On most cars, a few psi over recommended tire pressure is ok. But on some, depending on the actual tire you're running, every psi makes a difference. You have to do a little trial and error to figure out what feels best.

On my previous BMW, the recommended pressure was perfect. Good balance of ride comfort and fuel efficiency. Higher led to slightly (barely noticeable) higher fuel efficiency, but significantly worse ride comfort/handling.

On my Miata, I run 2 psi under recommended tire pressure. Then again, I run sticky summer tires on aftermarket wheels slightly wider than stock.

 

[unokitty]

No one tire setting is correct for all cars and all driving conditions.

That said, if you are talking about driving on the street, I would start with what is in your owners manual and raise or lower that by 5 or 10% per driving session and see what suits your driving style best.

For example, drive for a few days with 31 lbs. Then drive for a few days with 34 lbs. Then drive for a few days with 38 lbs. Higher tire pressure will give you improved gas consumption with a harsher ride. In wet or muddy conditions, lower tire pressure will give you better traction but will also use more gas.

I would also peruse any forums that are specific to your car and try to glean some information there. For example, when I had my Miata, Miata dot net was very helpful.

Best of luck,
Uno

 

[BUTCH1]

Huh? I guess you haven't heard the "inflate to sidewall" recommendation from a noted member..

 

[waggy]

Huh? I guess you haven't heard the "inflate to sidewall" recommendation from a noted member..

duh everyone knows that is the best thing to do. fucking newbs.

 

[Doppel]

Inflate to sidewall. Always.

 

[bruceb]

Your car sticker says 31PSI, but that is a compromise between handling and ride quality. For a car like that, I would try around 35PSI and see how it rides / handles. Then adjust a pound or two each way, until you like it. But do not run anywhere near max pressure on sidewall. Ride will be very very harsh.

 

[phucheneh]

There are basically three factors at play.

One is tire wear. The manufacturer's spec is usually fairly optimized for even wear. The weight/weight distribution of the vehicle, the tire size, the size of the wheel it's mounted on...lots of factors effect what pressure will make the contact patch flat and evenly loaded. Too much pressure, and the 'ballooning' of the tire lifts the edges of the tread away from the ground and pushes the center out. Which of course results in the center of the tire going bald first. Too little pressure, and the opposite occurs (feathering on both edges of the tire, more tread in center).

The other two things are handling-related. One is responsiveness. The other, I guess I would call 'adhesion.' Or grip. Traction. Ect. How much the tire 'sticks' to the ground.

Higher pressures mean a firmer tire, and generally better response. Lower pressures generally give more grip...just don't make a linear association between 'grip' and 'handling.' You've gotta balance it with that whole 'responsiveness' angle.

Most cars have a spec in the 29-33psi range. I wouldn't go under it. I generally (there's that word again...remember, I'm only generalizing here) like about 3-5lbs extra. Makes the common, widespread 'standard' of 35psi pretty appropriate.

The side effect of running a little high is also that treadwear is usually pretty optimal. I'd rather wear the centers a little extra than I would the edges...a bald center doesn't pose much safety risk. Bald corners are tread separation waiting to happen. Plus, most people don't check their tires very often...so if spec is 32, and I set it to 35...chances are, it'll be back down to ~30 by the time the car goes in for service again. So your 'average' pressure is around spec. And a gradual loss of pressure (especially when transitioning to colder weather) won't trip the tire light.

/overthink