U.S. CitiesCity-Data Forum Index
Celebrating Memorial Day!
Go Back   City-Data Forum > General Forums > Automotive
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old Yesterday, 10:53 AM
 
13,894 posts, read 12,679,478 times
Reputation: 18809

Advertisements

Quote:
Originally Posted by HumbleMerchant View Post
Why do people keep repeating this nonsense is way beyond me. If you don't alter the tire dimensions drastically, your door placard will show the correct pressure for your car. The pressure shown on the tire itself shows the maximum pressure this tire can safely be operated at.
How is it nonsense? You even countered your claim with "If you don't alter the tire dimensions drastically..."

Is a mechanic going to know if you altered your tires significantly? Id the mechanic going to be well versed in knowing if my SUV came with "P" rated, "C" rated, or is the current "E" rated the OEM ones? If the mechanic aired my tires to what my door says, they will be severely under inflated as my car came with "P" rated yet has "E" rated tires on it.

Likewise, someone who say has an F-250 that came with "E" rated tires, now all of a sudden put some "D" rated off-road tires on it, going by the door will over inflate the tires.

The rule of thumb for mechanics is that absent any knowledge of your tires in relation to your car, airing up a few pounds under the max will ensure they are not over nor under inflated.
Reply With Quote Quick reply to this message

 
Old Yesterday, 11:20 AM
 
342 posts, read 182,618 times
Reputation: 557
Car manufacturers test the car as a whole with the tires set to the specified pressure that's on the label.

Tires are made to fit more than one car, and tire manufacturers don't even come close to testing it on every car that can fit that tire size. Their max pressure is for the tire itself, and does not take into account how that effects the best performance of a particular car.

It's a free country and you can put whatever size tire you want on your car and set it to whatever pressure you want. But if you're not using a recommended tire set to a recommended pressure, that's all you if something goes wrong. Those 'technicians' at the shop who fill it to what the tires say are more than happy to sell you another set of tires.
Reply With Quote Quick reply to this message
 
Old Yesterday, 11:49 AM
 
Location: Billings, MT
9,340 posts, read 7,426,493 times
Reputation: 12916
YOU can do what YOU want. It is, after all, YOUR vehicle.
For me, I watch for tread wear.
If the tread is wearing mostly in the middle, I know the tires are over inflated; I need to reduce pressure.
If the tread is wearing on the edges, I know the tires are under inflated. I need to increase pressure.
For safety, I want the largest contact patch of the tread on the road surface. If the tires are running on the edges or the center of the tread, I do not have an appropriate contact patch, and my traction is compromised. That is unacceptable, at least to me.
If I want an immediate test, I make a few chalk marks across the tread, and drive the vehicle a hundred yards or so on a hard, clean surface (asphalt/concrete, no gravel on it). If the chalk marks are worn off evenly, good inflation. If the chalk marks are worn off on the edges, underinflated. Fix it. If the chalk marks are worn off in the center, over inflated. Fix it.


As for the inflation pressure on the tire sidewall, read the entire statement. It probably says "Max Load XXXX lbs. at XX PSI" Is your vehicle EVER loaded to the point where the weight on the tires meets that "Max Load" number? No? Then you do not need that inflation pressure!


Load Range inflation pressure? Well, the Jeep Wrangler Rubicon I used to have came from the factory with Load Range E tires. Inflation pressures recommended by Jeep? 33 PSI highway, 12 PSI minimum off road. Inflation pressure on the tire sidewall? 80 PSI!


It really doesn't take a Master's Degree in Mechanical Engineering to figure this out...
Reply With Quote Quick reply to this message
 
Old Yesterday, 11:49 AM
 
Location: Davidson, NC
109 posts, read 53,137 times
Reputation: 264
Quote:
Originally Posted by turf3 View Post
Well, I guess we know SOMEONE slept through physics class in high school!
Good one. Yes, I know air is roughly 80% nitrogen. I'm talking about nitrogen out of a nitrogen bottle which has typically been through a drier versus your typical air compressor setup in a garage.

Interesting read if you also slept through physics.
https://www.air-compressor-guide.com...-calculations/
Reply With Quote Quick reply to this message
 
Old Yesterday, 11:50 AM
 
Location: Myrtle Creek, Oregon
11,543 posts, read 11,904,621 times
Reputation: 18014
Quote:
Originally Posted by TheGrandK-Man View Post
My point is that the concept of following instructions has gone out the window, even among supposedly certified or otherwise qualified mechanics.

What's your definition of "better handling"?
The higher the inflation pressure the less likely a tire will roll onto the sidewall during high-G maneuvers. The Firestone/Ford fatalities were caused by inflating to the lowest recommended pressure to smooth out the ride. Tires popped off the rim and caused rollover accidents. People were killed. Firestone took the heat for tire failures, but it was Ford's recommended low inflation that caused the problem. Put another 8 PSI in the tires and there was nothing wrong with them.

I agree with the locals. Inflating to max tire pressure may lead to uneven wear. For my tires that have a max of 44 psi, I run them at 40. For my tires that have a max pressure of 55 PSI, I run them at 45, or 55 if I'm hauling a load that puts more than an additional 500 lbs. on the tire.
Reply With Quote Quick reply to this message
 
Old Yesterday, 12:01 PM
 
13,894 posts, read 12,679,478 times
Reputation: 18809
Quote:
Originally Posted by Redraven View Post
YOU can do what YOU want. It is, after all, YOUR vehicle.
For me, I watch for tread wear.
If the tread is wearing mostly in the middle, I know the tires are over inflated; I need to reduce pressure.
If the tread is wearing on the edges, I know the tires are under inflated. I need to increase pressure.
For safety, I want the largest contact patch of the tread on the road surface. If the tires are running on the edges or the center of the tread, I do not have an appropriate contact patch, and my traction is compromised. That is unacceptable, at least to me.
If I want an immediate test, I make a few chalk marks across the tread, and drive the vehicle a hundred yards or so on a hard, clean surface (asphalt/concrete, no gravel on it). If the chalk marks are worn off evenly, good inflation. If the chalk marks are worn off on the edges, underinflated. Fix it. If the chalk marks are worn off in the center, over inflated. Fix it.


As for the inflation pressure on the tire sidewall, read the entire statement. It probably says "Max Load XXXX lbs. at XX PSI" Is your vehicle EVER loaded to the point where the weight on the tires meets that "Max Load" number? No? Then you do not need that inflation pressure!


Load Range inflation pressure? Well, the Jeep Wrangler Rubicon I used to have came from the factory with Load Range E tires. Inflation pressures recommended by Jeep? 33 PSI highway, 12 PSI minimum off road. Inflation pressure on the tire sidewall? 80 PSI!


It really doesn't take a Master's Degree in Mechanical Engineering to figure this out...
They came with load range "C", 33 psi in any "E" tire will be very under inflated.

What year was your rubicon?
Reply With Quote Quick reply to this message
 
Old Yesterday, 12:08 PM
 
13,894 posts, read 12,679,478 times
Reputation: 18809
Quote:
Originally Posted by Larry Caldwell View Post
The higher the inflation pressure the less likely a tire will roll onto the sidewall during high-G maneuvers. The Firestone/Ford fatalities were caused by inflating to the lowest recommended pressure to smooth out the ride. Tires popped off the rim and caused rollover accidents. People were killed. Firestone took the heat for tire failures, but it was Ford's recommended low inflation that caused the problem. Put another 8 PSI in the tires and there was nothing wrong with them.

I agree with the locals. Inflating to max tire pressure may lead to uneven wear. For my tires that have a max of 44 psi, I run them at 40. For my tires that have a max pressure of 55 PSI, I run them at 45, or 55 if I'm hauling a load that puts more than an additional 500 lbs. on the tire.
Well, did they ever come to an exact conclusion? last I read it was a combination of design issues, but the low tire pressure recommended by Ford, against what Firestone has said should be, was the contributing cause that exploited the design issue.
Reply With Quote Quick reply to this message
 
Old Yesterday, 12:34 PM
 
Location: SWFL
22,120 posts, read 18,661,057 times
Reputation: 19825
Quote:
Originally Posted by jimazee View Post
Add more factors like: gas mileage, tire wear, winter/summer tires, leaky wheels (esp. aluminum wheels and potholes in the North country), and temperature changes to the formula...

No wonder manufacturers are trying to perfect airless tires...maybe they can invent an automatic refill system?

I use what's on the door sticker and check 'em occasionally, they always require some refilling and balancing ... ... good thing I have a garage and a compressor.

(remember when filling stations would sometime actually check the air and correct for drivers? ... or at least when stations had free air pumps, and cars had spare tires?)

Nothing to worry about.
Oh yes!! That's why I didn't have a clue as to how to put air in my tire the first time I had to do so! Also Daddy and hubby used to be "in charge " of that kind of stuff.

Quote:
Originally Posted by elhelmete View Post
LOL at believing one can feel 1PSI diff in an econobox on public roads.
Hey!!! My 2017 Hyundai Sonata Sport is Not an "econobox"!! It is a very comfortable mid-size sedan to me. It has fit 5 comfortably.

I have never had to add air for summer and winter before moving to SWFL!! EVERY time it gets chilly down here I have to add a lb or 2 of air. I even bought a compressor because my readout of low tires freaks me out! I set all of them to 32psi and people compliment my car on a comfortable ride. I also have 3 modes of driving....eco, sport and whatever. Lol, I use eco all the time.
Reply With Quote Quick reply to this message
 
Old Yesterday, 01:10 PM
 
Location: Metro Detroit Michigan
3,449 posts, read 940,720 times
Reputation: 2791
Just put in what the manufacture says they built it so they should know.
Reply With Quote Quick reply to this message
 
Old Yesterday, 01:17 PM
 
Location: Aurora Denveralis
5,290 posts, read 1,765,546 times
Reputation: 8005
Quote:
Originally Posted by TheGrandK-Man View Post
...running those cold pressures make the ride a tad rough for me...

...the steering is a bit too light and twitchy for my tastes.
And that's what's at the bottom of this thread: personal tastes. A little lower pressure for a softer ride and more steering feel, a little higher for better mileage - as long as it's within safe variation, there's no reason to religiously maintain the factory spec. And it does seem that you understand what "better handling" means by preferring lower pressure/better steering response.

Particularly on econo vehicles, OEM pressure is often is set high to maximize mileage, the opposite of setting it low to promote ride comfort. It depends on the vehicle and its market and is NOT some fantastically engineering-driven value optimized for all conditions and drivers. The overall range might be, but the exact number is chosen as much by the marketing department as the track engineers.

Quote:
It seems like the growing majority of owners and garages and service centers are running pressures higher than vehicle recommended, or at Max Cold on the tires.
The argument has been around for decades. Many of them. It's not new. Going up to the tire's cold limit or around 10% below OEM spec is a non-issue for tire safety, although if the difference between OEM and max is more than about 10-15%, it could make the handling too spidery for safe driving.

Otherwise, knowing how to calculate relative load psi is a good starting point for those who want to experiment. Or just meticulously following the door sticker if you think manufacturers are infallible.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply

Quick Reply
Message:


Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Automotive
Follow City-Data.com founder on our Forum or

All times are GMT -6.

2005-2019, Advameg, Inc.

City-Data.com - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 - Top