U.S. CitiesCity-Data Forum Index
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)
 
 
Old 11-25-2014, 08:35 PM
 
4,803 posts, read 10,163,085 times
Reputation: 8245

Advertisements

Whether I go to a dealership, a jiffy lube type place or private mechanic when I check my tire pressure afterward it's always around 37 or 38 psi. This is on a regular passenger car with standard tires. The information sticker on the door clearly states 30 psi and yet they all do it. When I get home I have to let air out.
Not a huge deal but I don't get it. What's so hard about inflating tires to the proper pressure and why should I have remind mechanics 38 psi is too high for most standard tires?
Anyone else have this problem?
Quick reply to this message

 
Old 11-25-2014, 08:50 PM
 
Location: City of the Angels
2,223 posts, read 1,521,436 times
Reputation: 5363
It could be that you're checking it when the tires are hot.
Check the pressure when they're cold and see if there is a difference as hot weather, extreme temperatures and other conditions can cause the air in your tires to expand, and PSI can subsequently increase.

How To Check Tire Pressure - How to Guides at DMV.org: The DMV Made Simple
Quick reply to this message
 
Old 11-25-2014, 08:59 PM
 
10,868 posts, read 41,128,193 times
Reputation: 14009
most likely the shops you're at are inflating the tires to the "max tire pressure" rated on the sidewall of the tire, and they're doing a poor job of it at that.

few will look at the factory posted tire pressures from the stickers on the car to know the correct inflation pressures.

I've found the same problem with cars serviced at quick lube centers, particularly with inlfations variations between the tires.

If you're paying attention to your car tire inflation pressures, probably best to tell the service folk to "not check the tires" and hope they don't.
Quick reply to this message
 
Old 11-25-2014, 09:31 PM
 
Location: Texas
5,586 posts, read 11,831,318 times
Reputation: 10545
Last time I checked, no car maker makes tires. The inflated pressure on the door is for the tires that it came with from the factory, not replacement tires. The guys will look at the tire makers max pressure to give you maximum fuel mileage. You should be thankful for that. I can just see my Bronco with 12.5 x 31 tires going down the road with 28 lbs of air.....until it's upside down in a ditch.......the tires take 50lbs.
Quick reply to this message
 
Old 11-25-2014, 09:39 PM
 
12,623 posts, read 12,065,272 times
Reputation: 17261
Quote:
Originally Posted by TrapperL View Post
Last time I checked, no car maker makes tires. The inflated pressure on the door is for the tires that it came with from the factory, not replacement tires. The guys will look at the tire makers max pressure to give you maximum fuel mileage. You should be thankful for that. I can just see my Bronco with 12.5 x 31 tires going down the road with 28 lbs of air.....until it's upside down in a ditch.......the tires take 50lbs.
There was an entire thread on this recently, seems half the people did not understand this concept no matter how it was explained to them.
Quick reply to this message
 
Old 11-25-2014, 10:07 PM
 
4,429 posts, read 3,103,104 times
Reputation: 5262
Why would you inflate to the MAX tire pressure on the tire?

Regardless of tire, it is still better to inflate to recommended tire pressure on car side door than MAX tire pressure on tire.

It is FOOLISH to inflate to MAX tire pressure
Quick reply to this message
 
Old 11-26-2014, 07:31 AM
 
Location: Central Texas
13,720 posts, read 24,608,598 times
Reputation: 9173
Quote:
Originally Posted by TrapperL View Post
Last time I checked, no car maker makes tires. The inflated pressure on the door is for the tires that it came with from the factory, not replacement tires. The guys will look at the tire makers max pressure to give you maximum fuel mileage. You should be thankful for that. I can just see my Bronco with 12.5 x 31 tires going down the road with 28 lbs of air.....until it's upside down in a ditch.......the tires take 50lbs.
You are missing the point entirely. The carmakers recommend a tire pressure for a specific tire size. They choose the tire pressure to produce a desired ride and handling combination. The maximum tire pressure on the sidewall has no relationship to the proper tire pressure unless the maximum is LOWER than what the carmaker requires.

A tire of a specific size, such as 215/70/15, has the same internal volume (within very small differences by brand), regardless of brand. If the carmaker says 28 psi with the OEM tire (which might have a sidewall rating of 36 psi) a replacement tire should be inflated to 28 psi even if the replacement tire has a diffierent/higher max sidewall number. The carmaker wants a specific contact patch and ride height, controlled by the air in the tire, not the sidewall rating.

Carmakers know there is a high probably their owners will choose a different tire as a replacement than what was originally on the car.

In truck tires where load range is often a factor the sidewall rating becomes important when tire pressure is higher. But if you replaced an OEM tire with a higher load range tire that does not mean you suddenly should put far more air in the tire.
Quick reply to this message
 
Old 11-26-2014, 07:49 AM
 
33,134 posts, read 39,067,107 times
Reputation: 28484
You ever tried using a different tire pressure gauge ?
Quick reply to this message
 
Old 11-26-2014, 08:10 AM
 
1,212 posts, read 1,350,242 times
Reputation: 1563
My experience with this is that you can run lower or higher pressure if you want. Lower pressure will give you a softer ride, but fewer miles per gallon. If you run lower pressure, over time, your tires will tend to wear more on the outer edges and you will need new tires sooner. People don't check their tire pressure all the time. Over time, especially when the temps are getting lower in the fall, the pressure declines and they need air. I run about 37 psi because the gas mileage is better and the tire wear is more even. The tires seem to last longer. I don't exceed the max pressure indicated on the tire. It is good to have all 4 tires inflated to about the same psi. I don't like running a vehicle down the road, especially the highway, with lower tire pressure. It is harder on the tires. You want the pressure up to the recommended level indicated on the tire, not to exceed the max.
Quick reply to this message
 
Old 11-26-2014, 08:36 AM
 
Location: Texas
5,586 posts, read 11,831,318 times
Reputation: 10545
Quote:
You are missing the point entirely. The carmakers recommend a tire pressure for a specific tire size. They choose the tire pressure to produce a desired ride and handling combination. The maximum tire pressure on the sidewall has no relationship to the proper tire pressure unless the maximum is LOWER than what the carmaker requires.
You're assuming that all tires of a given size are made exactly the same, they are not. Even tires that come as factory installed are not the same as those sold as replacement tires of the same brand and model. It is true, the car makers recommendation on the door is a compromise of ride quality primarily and decent handling for the factory installed tires, but neither are optimized. If you want better fuel mileage and better handling, max the pressure of the tire to what the TIRE MAKER says is a safe working pressure. The decreases rolling resistance. Most tires can be over filled by 10 lbs over the max pressure on the sidewall with no hazardous results. That info came from a tire maker. But instead of the offhanded remarks, if you don't want anybody fooling with your tires, tell them to leave them alone. But then, it's a lot easier to sound like intelligent at others expense when in fact you are making a fool of yerself with the cheap remarks.
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.


 
Please update this thread with any new information or opinions. This open thread is still read by thousands of people, so we encourage all additional points of view.

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
Similar Threads
Follow City-Data.com founder on our Forum or

All times are GMT -6.

2005-2018, 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