12 Inch Tire Pressure

[jrbauerjr]

Tire Pressure

I want to thank all of you that gave me original factory numbers and caution those of you that are filling to maximum sidewall pressure. If you spend any time around heavy vehicles, over the road trucks, mining equipment or Class A RV's you quickly and expensively learn that what is importaint is the load range of the tire and the axle loading (weight). Load range specs have not changed since they were introduced years ago. A load range G or H is the same as it was 20 years ago. Nor has the weight of the car changed that much (even though I'm 45 pounds heavier since 1990).

So go ahead and run the full sidewall rating and watch the centers of your tires wear out and your suspension components take a beating that they weren't designed for. Otherwise go to the tire rating books and match the load to the rating and determine the optimum pressure or use the OEM specs if the load rating is the same.

There are a lot of things that are more expensive than the savings from 5 more MPG.....

Older and wiser....

Jim Bauer

[GenevaDirt]

I want to thank all of you that gave me original factory numbers and caution those of you that are filling to maximum sidewall pressure. If you spend any time around heavy vehicles, over the road trucks, mining equipment or Class A RV's you quickly and expensively learn that what is importaint is the load range of the tire and the axle loading (weight). Load range specs have not changed since they were introduced years ago. A load range G or H is the same as it was 20 years ago. Nor has the weight of the car changed that much (even though I'm 45 pounds heavier since 1990).

So go ahead and run the full sidewall rating and watch the centers of your tires wear out and your suspension components take a beating that they weren't designed for. Otherwise go to the tire rating books and match the load to the rating and determine the optimum pressure or use the OEM specs if the load rating is the same.

There are a lot of things that are more expensive than the savings from 5 more MPG.....

Older and wiser....

Jim Bauer

load ratings and tire pressures are in the books with the OEM tires....not any after market tires. If you differ from the rating on the sidewall pressure then you run the risk of tire failure for that paticular tire whether you are over inflating or underinflating. Just ask the people that were involved in all the tire related roll overs in recent years. If a tire says 45 psi and you put 32 in it because that was an original rating in your book....then you are going to have a tire that feels like it is going flat and has more give in the sidewall making it unsafe to drive that way...so go ahead and go by what your book says no matter what the tire recommends.
Older does not make you wiser in some instences and you were the one that asked the question. If you knew so much then why ask it in the first place. I have been driving truck and such in a commercial aspect for over 25 years,,,, does that make me wiser? I do not think it does...at least I wouldn't just throw it out there and snub the people I asked to help me with something I didn't know just because I feel I am older and wiser.

[littlecar]

Thank you jrbauerjr. I agree, and having worked on cars all my and seen customers come back time and time again with tire issues from over/under inflation. I can tell you that its true, many problems can arise because of inflation issues. However, thinking it over, if the tread of your tire is 3 to 5" wide, you're not going to notice these problems as quickly or easily, perhaps not all due the narrowness of the tread. You could argue either way, but I use factory numbers for factory set ups. Aftermarket is different.

[littlecar]

Just pointing it out he never said what he was running on.

Is it factory fitment tires or something different?

[GenevaDirt]

Just pointing it out he never said what he was running on.

Is it factory fitment tires or something different?

doesn't matter at this point....if you do not have the tires the car came with ....then you are running after market tires and differant brands have differant pressure ratings. Just because they ar 155/80r/12's does not make them all use the same pressure. I have 3 differant brands and 2 of them max at 35 and 1 set max's at 45. Recommended pressure is on the tire...not the door jamb or in a book of a 20 year old car.

[littlecar]

What if the tires you run don't have a recommend psi setting on them? I know my yokohamas don't. What would you do then?

[Pu241]

What if the tires you run don't have a recommend psi setting on them? I know my yokohamas don't. What would you do then?

All passenger car tires by law must have a maximum inflation pressure listed on the side wall.
Usually in small print, but it's there. just have to look a little closer

[littlecar]

Yes, it does. I'm well aware of this. That is the maximum psi not the recommended psi.

There is a difference in maximum and recommended, or else they would have the same name, no?

So, are you recommending the maximum? Or something else?

[Pu241]

I run the maximum, you may not care for the ride though!
The recommended pressure depends on the size and type of tire as well as the vehicle weight!
The recommended pressure is also just that, a recommendation based on the above factors plus what the manufacturer determines is an acceptable ride.
So, if you can't stand the ride at Max. pressure reduce it till it's to your liking, but I wouldn't go less than 8-10 psi less than the max pressure.
Otherwise you will likely be in an under inflated condition which is just as bad as over inflation as far a tire wear and handling are concerned.

[littlecar]

It's very interesting to hear the opinions of people who aren't technicians. Please, no one take offense to that. I still value your opinions and contributions. As a full-time Ford technician and part-time tire tech. at another location, I find everyones opinion interesting.

[Pu241]

Well then Mr. Part-time tire tech,
What is your valued opinion of the "recommended" tire pressure using Falken 175 60 13 tires on Mazda 323 alloys with FMS lowering springs?
And of course we value your opinions and contribution, many thought they have been!

[littlecar]

Well, so much for not upsetting anyone.

If stock size, load and speed ratings are maintained, factory settings are best.

If you choose to change any of these, well throw it out the window.

That's all I'm saying. That information is correct, if follow the book. I'll be the first to tell you or anyone else that I don't follow factory specs in my own cars.

I didn't mean to upset anyone. Weekend warriors like many of the people on here are very smart and helpful. However, sometimes a better answer can be had. What most of you have is said is not wrong in any way. It just isn't what the factory calls for. When, some one asks for specs, I start with factory specs, then branch into my after market opinion.

As far your falkens are concerned, I don't think you give a Snot what I think anymore. I was just trying to help, so much for that.

[Pu241]

I wouldn't have wasted my time if I didn't want your opinion!
I know what I run them at(psi), but I'm not adverse to learning a better way.
You just come across a bit of a "know it all", and many people here have run these cars almost as long as you have been alive.
And their opinion counts for quite a bit to me!
You have yet to provide as much useful info.
Perhaps a run down on what to consider when running various size tires, wheels, and suspension components would be inorder.
Maybe, if done well it could be made into a sticky!
Now that would be valuable.

[bhazard]

NO! not at all safe

Been running them like that for 6 months with nothing bad happening, they arent even wearing unevenly, not that I really care about the wear. Theyre $20 spud specials (spuds is the junkyard I got them from). That even included the metro wheels they were on.

[turqfest]

I run 29 psi in front and 32 in the back (checked and filled cold), when the roads are wet so I don't spin out as must across the crosswalk paint at intersections. In the summer I go with 31 psi all the way around with no problems. 27 psi or whatever works all the way around if I get stuck in a snowstorm Seems to work for me.