Tire Pressure

[ferrethouse]

Tire pressure is a safety issue.

If 40 PSI compromised safety then the max pressure would be 40. There is no way in hell a tire manufacturer is going to expose itself to liable by making the max psi 50 if 40 compromises safety.

The reason 35 PSI is recommended is because that is what is required to operate it safely under max gross load. Since none of us drive it under max gross load it is fine to run higher.

From TireRack...

Higher inflated tires cannot isolate road irregularities well, causing them to ride harsher. However, higher inflation pressures usually provide an improvement in steering response and cornering stability up to a point.

I'll let them know that they are wrong

 

[kev4]

Well I'm kind of glad they didn't as I like 40 psi. I have 6500 miles on it and tire wear is even across the tire and going into winter I am even less concerned with being 5 psi over (hot reading).

http://i.imgur.com/Xai7enl.jpg
http://i.imgur.com/afMpu1P.jpg Saudi tire problem, do what you may, it's your car. Hopefully your ignorance won't cost harm to someone else.

 

[jimb100]

If 40 PSI compromised safety then the max pressure would be 40. There is no way in hell a tire manufacturer is going to expose itself to liable by making the max psi 50 if 40 compromises safety.

The reason 35 PSI is recommended is because that is what is required to operate it safely under max gross load. Since none of us drive it under max gross load it is fine to run higher.

From TireRack...



I'll let them know that they are wrong

While you're at it, let the Hyundai engineers and the Hancook engineers know that they are wrong, too.

I'm sure after reviewing your credentials they'll change the spec ASAP.

Look, you might run at higher PSI forever and not have a problem. Or, on some hot day you might be riding at sustained highway speeds and a flaw in a tire will be exposed by the higher pressure and thus, heat.

Is the ride really that much more to your liking?

 

[Roikins]

When I get the car, it was at 40, I noticed that it rides very stiff and I feel every bump, I lowered to 34, and it was much better ride, 2 days ago I was at dealership and asked them to inflate tires with nitrogen, and again when I left them the pressure was 38 at front and 36 at back. I don't know, they didn't check it right or what, but I lowered again to 34. I noticed that I have 1 PSI difference what my display shows and what manual pressure meter shows, it's digital and not one of those cheap ones.

 

[Mark_888]

If 40 PSI compromised safety then the max pressure would be 40. There is no way in hell a tire manufacturer is going to expose itself to liable by making the max psi 50 if 40 compromises safety.

The reason 35 PSI is recommended is because that is what is required to operate it safely under max gross load. Since none of us drive it under max gross load it is fine to run higher.

From TireRack...

Higher inflated tires cannot isolate road irregularities well, causing them to ride harsher. However, higher inflation pressures usually provide an improvement in steering response and cornering stability up to a point.

I'll let them know that they are wrong

When an auto manufacturer recommends a tire pressure, it is the cold tire pressure (which means car has not been driven for several hours, and ambiet temps are about 70 F).

For each 10 degrees difference in ambient temperature (away from 70 F), the tire PSI changes by about 1 PSI (up or down). In addition, tires get anywhere from 2 to 5 PSI higher (depending on driving speed) after being driven for awhile. This is because of the flexing of tire belts, which are typically made of steel or other material that heats up when rapidly flexed.

The net effect of the above is that if you put in 40 PSI cold tire pressure, by the time you have been driving on a hot day at 70+ MPH, you tire pressure could be about 45-48 PSI. Depending on the speed rating of the tire (H, V, Z, etc), it could be dangerous to the tire.

With regard to the handling of the car at a particular PSI, that is determined by the car manufacturer, not the tire manufacturer. Auto manufacturers are a little more concerned with ride comfort (to help sell cars), so you can increase tires to a few more PSI than the auto manufacturer recommends, but if you go too far beyond that then you could be affecting the safe handling of the car.

With regard to the Tire Rack quote, they mean "somewhat" higher. At some point the handling will actually diminish if you go too high, and the safety of the tire itself can be compromised if PSI is too high. As stated before, the risk changes depending on ambient temps, driving speed, and tire speed rating (H. V, Z, etc).

 

[Mark_888]

When I get the car, it was at 40, I noticed that it rides very stiff and I feel every bump, I lowered to 34, and it was much better ride, 2 days ago I was at dealership and asked them to inflate tires with nitrogen, and again when I left them the pressure was 38 at front and 36 at back. I don't know, they didn't check it right or what, but I lowered again to 34. I noticed that I have 1 PSI difference what my display shows and what manual pressure meter shows, it's digital and not one of those cheap ones.

Cars are shipped with PSI at higher than normal levels to make sure they survive the boat trip without having to be refilled. they are supposed to be reduced to recommended levels during dealer prep.

I would assume that your own digital gauge is more accurate than the internal one, which is mainly there for safety and fuel efficiency purposes, to flag grossly underinflated tires.

 

[Midnightsun]

When I get the car, it was at 40, I noticed that it rides very stiff and I feel every bump, I lowered to 34, and it was much better ride, 2 days ago I was at dealership and asked them to inflate tires with nitrogen, and again when I left them the pressure was 38 at front and 36 at back. I don't know, they didn't check it right or what, but I lowered again to 34. I noticed that I have 1 PSI difference what my display shows and what manual pressure meter shows, it's digital and not one of those cheap ones.

all those gauges are rather cheap even if you think otherwise. Being digital or pay a few $ more has no bearing on precision. Some gauges are off by up to 5 psi that I have seen. In fact my very good friend who ones a tire shop just put on my winters. The checked pressure on the door jamb and inflated to 35psi as recommended however when I left my indicators showed 40 all around except for 1 which was 39. When I got home I checked with my personal gauge and it coincided with the TPMS numbers. Called my friend and he is having a gauge calibrated to use as a tester to ensure all his gauges read correctly in the future.

Heck we even have one in the shop that reads 7 psi more than actual. You really need to check these things out and never assume they read correctly.

I have one of these on a compressor at home. Verified to be pretty much dead on and highly recommended. [ame="http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=cm_cr_pr_product_top?ie=UTF8"]Amazon.com: Astro Pneumatic 3018 3-1/2-Inch Digital Tire Inflator with Hose: Automotive[/ame]

 

[Mark_888]

I have one of these on a compressor at home. Verified to be pretty much dead on and highly recommended. Amazon.com: Astro Pneumatic 3018 3-1/2-Inch Digital Tire Inflator with Hose: Automotive

I have this portable one (not attached to compressor), which is also very accurate:
[ame="http://www.amazon.com/Accutire-MS-5510B-Racing-Tire-Gauge/dp/B000BNS7Y2/ref=sr_1_31?s=automotive&ie=UTF8&qid=1415458977&sr=1-31&keywords=air+gauge+tire+pressure+digital"]Amazon.com: Accutire MS-5510B Racing Tire Gauge: Automotive[/ame]

 

[Nikgen]

all those gauges are rather cheap even if you think otherwise. Being digital or pay a few $ more has no bearing on precision. Some gauges are off by up to 5 psi that I have seen. In fact my very good friend who ones a tire shop just put on my winters. The checked pressure on the door jamb and inflated to 35psi as recommended however when I left my indicators showed 40 all around except for 1 which was 39. When I got home I checked with my personal gauge and it coincided with the TPMS numbers. Called my friend and he is having a gauge calibrated to use as a tester to ensure all his gauges read correctly in the future.

Heck we even have one in the shop that reads 7 psi more than actual. You really need to check these things out and never assume they read correctly.

I have one of these on a compressor at home. Verified to be pretty much dead on and highly recommended. Amazon.com: Astro Pneumatic 3018 3-1/2-Inch Digital Tire Inflator with Hose: Automotive

Did you have it calibrated? If not, how do know it's really dead-on?

 

[Midnightsun]

Did you have it calibrated? If not, how do know it's really dead-on?

I happen to own a hydraulics shop and we do have a couple of calibrated gauges. I have verified the pressure with one of the calibratd ones just for shits and giggles and yes it was accurate to with in .3 psi. As in the business, you simply mark the gauge with a + .3 psi and now you know exactly where you are at each time you take a reading.

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[Nikgen]

I happen to own a hydraulics shop and we do have a couple of calibrated gauges. I have verified the pressure with one of the calibratd ones just for shits and giggles and yes it was accurate to with in .3 psi. As in the business, you simply mark the gauge with a + .3 psi and now you know exactly where you are at each time you take a reading.

Ok, thanks - unfortunately, most of us don't have access to calibration for our tire pressure gauges, but I suspect that the better gauges are pretty darn close right of the box - certainly good enough for the end use, at least.

 

[Midnightsun]

Ok, thanks - unfortunately, most of us don't have access to calibration for our tire pressure gauges, but I suspect that the better gauges are pretty darn close right of the box - certainly good enough for the end use, at least.

The easy way is to double check with your on board tpms. If your hand held gauge differs most likely it is the hand held one which is bad. Look at it this way. If you fill to X pressure with gauge X, and the readings are all pretty much the same on your dash, this means you have 4 different gauges giving you the same readings compared to gauge X. See my point?

 

[Nikgen]

The easy way is to double check with your on board tpms. If your hand held gauge differs most likely it is the hand held one which is bad. Look at it this way. If you fill to X pressure with gauge X, and the readings are all pretty much the same on your dash, this means you have 4 different gauges giving you the same readings compared to gauge X. See my point?

Sure - my handheld generally matches the TPMS (though TPMS only deals in 1 psi increments).

 

[Roikins]

Cars are shipped with PSI at higher than normal levels to make sure they survive the boat trip without having to be refilled. they are supposed to be reduced to recommended levels during dealer prep.



I would assume that your own digital gauge is more accurate than the internal one, which is mainly there for safety and fuel efficiency purposes, to flag grossly underinflated tires.

That's what I thought too, but reading posts after your post, got really confused Now I don't know which readings to trust, because my pressure gauge wasn't calibrated, but 1 PSI off it's not that big of a deal, I live in South Florida, and that's why I try to keep the pressure close to recommended , because in hot weather driving on highway for more than 15 min, the pressure increases for 3-4 PSI more than when it was before I start driving. And I really don't like stiff drive, that's why I asked to fill up with nitrogen, and when we got cold front coming in, the TPMS light comes on right away in morning , I got the compressor as well with automatic shut off when it gets to pressure i program , but the compressor is portable small, from the Walmart, I would say the cheap one so I could put it where the spare tire is out of way. But at least I can inflate the tires if needed without going to gas stations , I liked those gauges what was mentioned from Amazon, I don't have that cool one
What else I noticed that before the driving all tires was equal pressure but after driving a while the readings from each tire was different, by at least 1 PSI, some times even 2 , I think it's because doesn't show exact pressure like for example the pressure could be one tire 34,7 and other 34,1 and after driving the 34,7 and 34,1 would be different by 1 PSI. Just my thoughts, sometimes I even have a readings for each tire different , but I guess it's not that big deal if your front left tire is 1 PSI more than front right tire,or vice versa, I didn't feel that the car would leaning towards to that side which has lower pressure.

 

[Roikins]

all those gauges are rather cheap even if you think otherwise. Being digital or pay a few $ more has no bearing on precision. Some gauges are off by up to 5 psi that I have seen. In fact my very good friend who ones a tire shop just put on my winters. The checked pressure on the door jamb and inflated to 35psi as recommended however when I left my indicators showed 40 all around except for 1 which was 39. When I got home I checked with my personal gauge and it coincided with the TPMS numbers. Called my friend and he is having a gauge calibrated to use as a tester to ensure all his gauges read correctly in the future.

Heck we even have one in the shop that reads 7 psi more than actual. You really need to check these things out and never assume they read correctly.

I have one of these on a compressor at home. Verified to be pretty much dead on and highly recommended. Amazon.com: Astro Pneumatic 3018 3-1/2-Inch Digital Tire Inflator with Hose: Automotive

Well that one is really nice, I like it, just made a order from Amazon

 

[Monolith2001]

http://i.imgur.com/Xai7enl.jpg
http://i.imgur.com/afMpu1P.jpg Saudi tire problem, do what you may, it's your car. Hopefully your ignorance won't cost harm to someone else.

I'm afraid I know very little about your tire problems in Saudi Arabia as I live in the US. Tire pressure is not a static as it changes based on weather and driving conditions. I am pretty certain that being +5 psi (my hot reading in mid September) above Hyundai's cold recommendation was not a major safety hazard but probably closer to expected and when I deflated them to 35, they were probably less than 35 cold.

The good thing about this thread as it made me actually go check my pressures since I haven't since mid September and they are 37/38 cold today (was cool last night) and I am very comfortable with that. If I see a white Genesis (assuming that is your car in your sig), I'll be sure to slow down so I don't blowout in front of you from having 3-5 psi more than Hyundai's recommendation though I am 10-13 under the tire limit.

 

[kev4]

I'm afraid I know very little about your tire problems in Saudi Arabia as I live in the US. Tire pressure is not a static as it changes based on weather and driving conditions. I am pretty certain that being +5 psi (my hot reading in mid September) above Hyundai's cold recommendation was not a major safety hazard but probably closer to expected and when I deflated them to 35, they were probably less than 35 cold.

The good thing about this thread as it made me actually go check my pressures since I haven't since mid September and they are 37/38 cold today (was cool last night) and I am very comfortable with that. If I see a white Genesis (assuming that is your car in your sig), I'll be sure to slow down so I don't blowout in front of you from having 3-5 psi more than Hyundai's recommendation though I am 10-13 under the tire limit.

I am sure you know best. No need to rely on expert design and testing. Take care of your family and loved ones. They rely on your knowing what Hyundai should have written on the inside of your drivers door. PS. no need to continue with this conversation. You can lead a horse to the water bla bla bla...

 

[Roikins]

I'm afraid I know very little about your tire problems in Saudi Arabia as I live in the US. Tire pressure is not a static as it changes based on weather and driving conditions. I am pretty certain that being +5 psi (my hot reading in mid September) above Hyundai's cold recommendation was not a major safety hazard but probably closer to expected and when I deflated them to 35, they were probably less than 35 cold.



The good thing about this thread as it made me actually go check my pressures since I haven't since mid September and they are 37/38 cold today (was cool last night) and I am very comfortable with that. If I see a white Genesis (assuming that is your car in your sig), I'll be sure to slow down so I don't blowout in front of you from having 3-5 psi more than Hyundai's recommendation though I am 10-13 under the tire limit.

Who is from Saudi Arabia? Somebody here?
Didn't notice anyone.
Don't worry about me blowing your tires on front of me, I'll notice you driving from that rattling sound of your car due to the overinflated tires.