Highest Safe Air Pressure?

[Chuck]

I was wondering what is the highest safe air pressure?

[tbaleno]

It depends on the tire and what you mean by safe.

But generaly 100psi is where you should start getting nervous.

By then I'm sure you will get a bunch of distortion on the tire so you wouldn't want to run anywhere near that high since there realy is no benefit to it.

[Chuck]

Just a guess, but before it gets hazardous, uneven wear is probably an issue.

[tigerhonaker]

Well here is my 2-Cents on tire pressure as if this has not been discussed many times in the past on multiple

Forums. Makes no difference though the question has been asked so here is my response.

My original tires on my HCH II at the Sidewall says,

{44 psi Maximum Tire Pressure}

So I have decided that if the Manufacture says this is the (Maximum) I will go with it and not ever give it another thought.

Now that is what I have decided. There are a great many Hypermilers that choose to run their tire pressures at 60 psi to I think 70psi. I have not read in any Forum about even {1-Blow-Out} from them running higher tire pressures. So I think it just comes down to a "Personal-Choice" on what an owner feels comfortable with.

I think one of the differences that owners have commented on with running higher tire pressures is the "Ride-Quality" becomes much Harsher/Firmer with the increased tire pressures. Other than that one thing being mentioned I have not really heard or read any other negative comments revolving around running the higher tire pressures.

Terry (tiger)

[brick]

I'm going to go with the engineers on this one, and say that max sidewall is the maximum cold pressure that you can run with the intended safety margin. I'm quite sure that you could run 150% of that and be fine most of the time, but that's not what the designers intended.

[tbaleno]

Harsh ride also means harder on the suspension. So if you have bumpy roads you might think you can handle it, but you should be aware that you may be shortening the life of your suspension. That's a decision you have to make. Also in the snow traction suffers and i believe stopping in the snow suffers.

As far as the intended saftey magin goes. I don't think thats 100% true. no one said the max sidewall pressure had anything to do with saftey. It could be some law or other factors such as load rating or something. Why do most models of tires have the same number? It can't be because all tires have the same failure points.

Next time I talk to one of the engineers I'll ask them to clarify.

[johnf514]

The benefits of heightened sidewall pressures are noticeable, however, one must consider what is riding on those tires.

If you have a small runabout that you use to commute solo to and from work on low(er) speed roads, higher sidewall pressures are acceptable. Carting the family around with the possibility of a blowout? Doesn't seem worth the extra MPGs.

Just my $.02. If the tire says XXpsi, stick with it.

[tbaleno]

Actualy higher pressures are better and will likely reduce the chance of a blowout under higher load.

If you have a lot of weight in your car you chances of a blow out are GREATER at LOWER psi than higher psi.

Or as the engineers say "load capacity increases with PSI" Nothing wrong with being at max sidewall if thats all you feel safe with. Just remember that you are putting your family in danger if the PSI gets TOO LOW.

For those of you that drive a fully loaded car to get air in before a trip and only put in the psi that the factory recomends (such as 32 or 36 or whatever) that that number is the COLD rating so since air expands when it gets hot you are actualy putting in LESS air than the manufacturer recomends and are running on an underinflated tire. VERY DANGEROUS. Check the tire pressure before the car has been moving and before the sun heats up the tires. Thats when they should read at least what the manufacture recomends. When you get to the pump at the gas station I can gaurantee the PSI has gone up and thats not a bad thing.

So remember the rating is COLD rating. So measure your tires when they are COLD or you will definatly be underinflating them if you fill to the manufacturers recomended PSI when they are WARM.

Bahh.. Enough babbling from me. Just trying to clear some misconceptions.

[johnf514]

Originally Posted by tbaleno

Actualy higher pressures are better and will likely reduce the chance of a blowout under higher load . . .

I couldn't agree more - I run my Taurus at max sidewall (44 PSI) which expands to roughly 46/48 PSI on the roads. 30's are way too low for the tires we're talking about to be run at.

However, 60 PSI? In the heat of a FL summer, I might be leery to make an extended commute with twisties and some high(er) speeds involved. Recall that I speak from the position of a mid-sized vehicle driven as FE as possible.

Anyone in the hot climates run high PSI (55+) that can comment on any of this?

[GaryG]

Here is my two cents:

I jumped to 40psi right away when I noticed that it came from the factory that way. The tires (one or two) were dropping psi to fast for me and I cranked them to 44psi (Max Side Wall). Notice a nice jump in MPG and kept them there.

Later, had a damaged tire replaced and told Goodyear to make sure they put all tires at 44psi. Notice my MPG was better, and when I check the pressure, they were above 50psi.

Pushing my 2,500 pound boat back in the garage takes two people at a running start with the tires at Max SW, 50psi to reach the speed it takes to clear the lip on the floor. If my tire pressure drops below 45psi, it take three people to roll up that inch or so lip. Below 40psi, forget it, I pump the two tires up.

Bottom line, 52psi is the most I push my tires too.

GaryG