Tire pressure question

[raddksn]

Just finished brake job on grandsons "99" dodge avenger, tires are all low he's running after market wheels and tires. Do I still set psi to the door sticker? Tires are 215/50R17 the side wall says 44psi max, do I need to up the pressure?

 

[pauleyman]

Tire pressure varies car to car. Thats why its on the door. Tire pressure on the tire is the MAX it will do, not what you should inflated it to.

 

[raddksn]

I understand sidewall psi is max, I'm just wondering being tire is such low profile do I up the psi or still set to door sticker?

 

[BFBOB]

pauleyman is right to a point. Where it differs is if you're running a very different type of tire. If the vehicle was designed for bias ply tires, you should use higher pressure in modern radials. Likewise, a much lower profile tire must have higher pressure to avoid wheel damage (your 50's qualify compared to the originals). Check what the OE tire was and choose accordingly.

Speaking for myself, I generally keep tires close to the max to help gas mileage and load capacity, since I'm usually carrying a pretty good load. There's really not a simple answer. Take your best guess and watch the tires carefully for signs of over-under inflation: uneven wear in particular. Wear on the outer edges=underinflation, wear in the center=overinflation. Look at the rear tires for this; fronts can wear on the edges for other reasons, like alignment/suspension problems.
Overinflated tires can also feel excessively bouncy, kind of like worn shocks.

 

[LB-1911]

I understand sidewall psi is max, I'm just wondering being tire is such low profile do I up the psi or still set to door sticker?

215 - 50R 17 is listed as an optional size for a "99" @
http://tire-size-conversion.com/tires/Dodge/Avenger/

What size(s) are referenced on the door sticker?

 

[raddksn]

Boy do I feel stupid, says on the door 215/50R17!

Thanks guys!

 

[Jinks]

Another guide is to inflate to your preferred pressure with the tires cold. Then drive at highway speed at least 50 miles to bring the tires to full temperature. Correctly inflated tires should increase pressure about 10%. Your 44 psi. would read about 48/49 psi. If it reads more than 10% you're under inflated, less than 10% you're over inflated.

 

[volleyball]

I have found that 44psi tires tend to work best around 40 psi to start. You can up or lower a bit from that depending on what works best.
The numbers on the sticker are for the original tires with a smooth ride.
Upping the pressure as long as you don't go too high will result in better performance and longer mileage.

 

[Leadberry]

Recommended tire pressure is related to the physical characteristics of a certain tire/wheel size and load weight. This is why every vehicle has its own recommended tire pressures. Tires have a rated maximum pressure they can safely hold, but this has nothing to do with what pressure may be best for a certain loading. Max tire pressure is a property of the tire, whereas door sticker pressure is a property of the vehicle.

Some German cars still give you a range of tire pressures to use for different passenger and cargo loadings. Some older American cars would give you multiple recommended tire pressures for optimal handling and for increased ride comfort. Some Asian cars provide recommended pressures for just a driver and for a full passenger loading. There is no single right or wrong tire pressure.

For most modern American and Asian vehicles, the pressure provided on the door sticker is based off of the physical characteristics of the OEM size tire, and will give you what the manufacturer has determined to be the best balance of handling, fuel economy, and comfort.

 

[brass89]

so long as they're not above the max psi listed on the sidewall, it's better to err on the high side than low. lower pressures will cause more issues such as handling, hydroplaning in wet/slick conditions, will cause tires to heat up and increase risk of a blow out. just make sure you use a gauge (always good practice) but especially for low-pro tires since they can appear 'good enough' and be nearly flat due to the short/stiff sidewall. doesn't leave much room for error since the rims are already so close to the tire itself. a low/flat tire even being driven for a short distance will allow the rim to cut the inside of the tire and shred the rubber inside without showing much more than a scuff on the outer sidewall and increase chances for a blowout substantially.

glad you found the info you needed.

 

[gene mosler]

That's all good info, but.........what is frustrating is I have 3 gauges ( of different types) and they all read differently. Guess I'll just use the average. So the question is, how do you know that the gauge you are using is actually correct. It's like a thermometer, if you need to be accurate, is it?

 

[c4cruiser]

The "Max pressure" listed on the sidewall is for the max air pressure to use for seating the tire on the wheel bead. If it takes more that that value, the tire installer should be deflating the tire, removing it from the wheel ad figure out why the tire is not seating.

I would start with inflating the tires to the recommended cold pressure as shown on the door sticker. Drive the car to get a feel for handling and ride. Then you can add or decrease the pressure by a couple pounds to see what that change does.

A 40 psi pressure or more on a passenger car is gong to result in a pretty harsh ride and you can expect increased tire wear at the center of the tire. As mentioned, if the car is driven at freeway speeds over a long period of time, the heat generated from that can easily add 3-5 psi. The listed door tag figures are really for a comfortable ride, gas mileage and decent handling.

Even when I tow my 7K lb car trailer with my pickup, I very seldom increase the truck's tire pressure beyond 40 psi.

 

[brass89]

What type of gauges are they? If they're more than 1 psi off from each other, time to get rid of them and get a more reliable gauge. Used to use one of the milton pencil style no frills gauges at the shop, everyone did. They come in various ranges, mine was 20-120psi. All our gauges read the same unless there was human error involved. If I checked the pressure on a tire and 2 other guys came behind me and checked with their gauges, we all got the same reading. You can find them online or at local parts stores for under $10.

That would frustrate me too and leave me with little to no faith in the gauge. Yes it needs to be accurate (within reason, it's not a precision tool like a micrometer). More than that, it needs to be consistent. We never had any way to really 'calibrate' or check them at the shop, if we were unsure we'd compare to everyone else's. If they all read 25psi and one read 22, it hit the garbage bin because obviously there was something wrong with it.

 

[c4cruiser]

That's all good info, but.........what is frustrating is I have 3 gauges ( of different types) and they all read differently. Guess I'll just use the average. So the question is, how do you know that the gauge you are using is actually correct. It's like a thermometer, if you need to be accurate, is it?

I have a large Longacre analog tire gauge that I bought a couple years ago for around $75. I also have a nice smaller digital gauge that cost me $25 and the readings on each are within a half-pound of each other. I have a tiny analog gauge that I got in a goodie bag at a car show and it reads exactly the same as the Longacre gauge. Go figure....

 

[brass89]

c4cruiser, true. higher inflation values will create a 'harsher' more firm ride (we used to call it riding like a log wagon). you have to take into consideration the difference of tires though too. for a regular car or truck tire, you're right but for low profile 'performance' style tires they need to be pretty full. on a standard radial, you have plenty of room for the sidewall distance in the tire to provide a little cushion when rolling over bumps. low profile tires (true low pro's) only have maybe 1.5"-2" of sidewall. if you let some air out to 'soften' the ride you're risking the rim bottoming out. low profile tires in and of themselves will not provide a comfy ride by design. they all ride rough(er) than standard touring radials or lt truck tires.

 

[volleyball]

The "Max pressure" listed on the sidewall is for the max air pressure to use for seating the tire on the wheel bead. If it takes more that that value, the tire installer should be deflating the tire, removing it from the wheel ad figure out why the tire is not seating.

I would start with inflating the tires to the recommended cold pressure as shown on the door sticker. Drive the car to get a feel for handling and ride. Then you can add or decrease the pressure by a couple pounds to see what that change does.

A 40 psi pressure or more on a passenger car is gong to result in a pretty harsh ride and you can expect increased tire wear at the center of the tire. As mentioned, if the car is driven at freeway speeds over a long period of time, the heat generated from that can easily add 3-5 psi. The listed door tag figures are really for a comfortable ride, gas mileage and decent handling.

Even when I tow my 7K lb car trailer with my pickup, I very seldom increase the truck's tire pressure beyond 40 psi.

I disagree with the entire statement. Where did you get the "fact" that the max psi was for installers? The oddest thing I've heard here in awhile.
40 psi doesn't give a harsh ride. You'd have to be used to sitting on your sofa if a firm tire feels harsh. At 32 a tire will feel squirrely. You have to drive very moderately, especially around turns or else your front tires wear out on the outside edge because they are turning under the vehicle. You lose a lot of contact area on the most important tire at the moment.

 

[WhiffySpark]

50 series are hardly low profile. 32 psi is what I would run

I have 40/45 on truck and only run 35

 

[brass89]

i've had a ton of customers who complained about 36psi on most passenger vehicles (cars and minivans, even some suv's) being too firm of a ride. i wouldn't go any lower than 30, usually ran mine at 32-33. i'm not sure what tire you're running that's squirrely at 32psi, i ran mine over 100mph no issue. combination hwy and city driving, with some curvy backroads thrown in. no edge wear on hankook's. both a civic and cobalt. unless you're racing or something, even 28-29 won't be hard to handle around corners (driving like a sane person) whether it's a ram1500 or a jag vanden plas. my boss ran 32psi on his denali even pulling his boat, it wasn't squirrely at all. i suppose to each their own. granted harsh is subjective, but to say 32 (within the acceptable recommended range on most door stickers with some variance 29-35 depending on the make/model) is somehow dangerous or could cause instability during legal city/hwy driving is a little off. sorry.

 

[Onewolf]

I disagree with the entire statement. Where did you get the "fact" that the max psi was for installers? The oddest thing I've heard here in awhile.
40 psi doesn't give a harsh ride. You'd have to be used to sitting on your sofa if a firm tire feels harsh. At 32 a tire will feel squirrely. You have to drive very moderately, especially around turns or else your front tires wear out on the outside edge because they are turning under the vehicle. You lose a lot of contact area on the most important tire at the moment.

40 PSI would feel like driving on Fred Flintstone stone wheels for every car I have owned over the last 20 years. BMW, Porsche, Infiniti, etc. I keep my fronts around 32 and rears around 34.

 

[volleyball]

Different pressure is like the firmness of your bed. You get used to what you have and something new won't feel right. Give it a few weeks and you may not want to go back.
I had a sedan and while it was in for service, the dealer loaned me a CUV of the same chassis. Just driving the speed limit of the corners made me tap the brakes as the lean was something I wasn't used to. My sedan was much more sure footed at a much quicker speed. I didn't get that CUV.
My friend drives like my grandma did change his same sedan for the CUV and did notice but only after I pointed it out.
You do feel more with higher pressure just as you do with going with a performance tire of the same size compared to that cheap basic tire. But you also feel much more confident in an emergency or just changing lane over a rough road.
If I were selling tires, keeping the pressure at the door sticker is good for business. Tires will wear out much faster and need replacing sooner. If the customer wants a soft ride, they pay to play. Nothing wrong with that. Same with the guy who smokes 5000 miles of rubber off going 20 feet.

 

[tdkkart]

So. Much. Wrong. Here.


Since when are tires so misunderstood??

 

[Rod N]

So. Much. Wrong. Here.


Since when are tires so misunderstood??

lol
I'm still chuckling on 17" being low profile.
I'd just use what's on the door or get a pyro meter.

 

[tdkkart]

I'm still chuckling on 17" being low profile.

Heh,
Wonder what they think of the 275/40-20's on the back of my car, or the 295/30-20's that will likely be the next pair??

yep, door post numbers work for me too........

 

[TAMPAGT07]

My wifes deville has 245/35/20's... We have run 40psi for years, it seems to wear out the tires evenly... When I ran 32 psi, it seemed like the edges wore out before the middle..It does ride a little firm though..

 

[saryon7]

Just fill most normal tires to 32-35psi. Filling them toward the higher range equals a harsher ride and better gas mileage. It is also easier to turn the steering wheel. The lower end is a softer ride and lower fuel mileage. Steering wheel is harder to turn. I have had customers complain the ride is too rough at 35 psi. I can't really tell the difference. If you see the tire outside edges wearing too quick it can mean it is under-inflated, and if the center of the tire is wearing too quick it can mean it is over-inflated.
The max tire rating is used for when the vehicle is loaded down with weight near its maximum carrying load.

 

[brass89]

I always ran my tires around 32-33psi on a smaller car (civic and cobalt). Drove 100mi a day round trip to work for over 6yrs and both got similar mileage, around 34mpg with 80% hwy and 20% city driving. It probably would have been better running at 60mph rather than 65-75+. I rotated them every other oil change and despite the brand typically got 60k mi out of my low end tires without them going completely bald. Uneven tire wear also has to be considered with driving style and alignment maintenance. I think the size of the wheel doesn't really have much to do with whether or not it's low profile, low profile means the height of the rubber from road to rim. A 17" wheel on 44" super swampers isn't low profile. Michelin makes a 335/35-r17, so yea a 17" tire can be low profile. (typically called low pro when they're ***/40 and under)

 

[stikman56]

Cold tire pressures are figured at 65 degrees. That's important when you're checking them. If they're hotter the pressures will be higher and colder, lower.