Overinflated tires

If you do happen to hit a pothole, you could end up damaging something more than just the tire... rim, ,suspension, alignment. Chances are better with that higher pressure I would think.

 

I run 44/42 normally as it is my wife's daily driver, and she wouldn't want the ride any harsher than that. When I take a solo trip, I am comfortable at 50 with my 44 max tires.

 

I had to check my calendar to confirm this wasn't an April fools post.

If you did a search, you'd find lots and lots of posts/opinions on this subject. My guess is this is probably the most discussed topic on this forum.

 

I personally do not think that running your pressures up to 50psi is a very good idea. If you get a 1.5 mpg bump (no punn intended) over stock that's what?....about a 15 mile increase in tank range? That's if you can quantify a real 1.5 MPG delta. We'll presume that you can for the purposes of this post.
Balance that increased range against the possibility of exacerbating an already rattle prone interior, and against an (albeit slight) increase in the possibility that you'll suffer tire and/or suspension damage from whamming into potholes with board-stiff tires.
In my never to be humbled opinion, the increased fuel efficiency is pretty insignificant.
The consequences of a catastrophic tire failure, and possible insult to other suspension (and interior) components are simply too great to gamble over this slight benefit.

But hey…..I’m a live and let live kinda guy! As long as you’re not hauling crumb crunchers around…I’d say it’s your car and you should be allowed to do as you please.

JMHO....

 

Hi Chief: Crumb crunchers.......I like that !!!!!!!!!

 

Do overinflated tires cause more tire wear and increase stopping distances? I have read that the center of the tread will wear faster, requiring premature replacement. I would question the advisability of overinflating if this is true.

 

This is not true. Within reason, higher pressures increase tread life, improve handling and traction. The cost is in terms of NVH (noise vibration harshness). It is all in how you drive, where you drive, and what value judgments you make. By within reason, I mean max sidewall or slightly above.

 

+1:rockon:

In addition, uneven tread wear from over inflation was a bigger problem with old bias ply tires. Most radials don't have that problem at reasonable pressures. Under inflated or normally inflated tires (and their wheels) are more likely to be damaged by hitting potholes or curbs.

 

Unless, of course, you take it on the beach for some dune romping.

 

When I was active at a different efficiency forum, a number of regulars would not publicly admit to their tire pressures, out of liability fears. But they did acknowledge exceeding 50.

Some of them pointed to an outside article by a police trainer / stunt show driver, who used 100. But for liability reasons, his department stuck to sidewall max for patrol vehicles.

Prii come with several different brands/models of tires, and I thought one of them has (or had) a sidewall rating of 51 psi. Mine have the same 44 rating as yours, so that is my limit.

Center wear was a problem in the old days with bias ply tires, as they would bulge like a balloon. Modern radials have multiple steel belts around the tire circumference, just below the tread. These steel belts don't bulge out at anything close to reasonable pressure.

Increased tread life is one of the common reasons for using higher pressures, at least up to sidewall max. After seeing it greatly reduce edge wear on a past car, I'm a believer.

 

In 2001 I bought a Prius. For the first 10k miles or so, I followed Toyota's pressure rec. The excessive tire edge wear was obvious. Then I went to the tire sidewall max pressure in front, and -2 psi in the rear. The reasons for that diff can be found in PC archives.

Tread wear (edge to center) balanced out, mpg improved, and handing (subjective) also improved. For subsequent tires on that car, my guideline was on the tire sidewall, not the Prius doorframe.

Over the years we have indeed beat this horse (perhaps not yet dead), but I find that the doorframe rec. tends towards "comfy". Not long tire life, not emergency handling, and not mpg. I don't know what the doorframes say nowadays; perhaps Toyota has joined me? Or not.

But the major issues here are: Safety - if you feel that higher inflation gives you less control over the vehicle, reduce it! Tread life - but then of course you'd need to measure it. The $20 Asian digital calipers do this very well. Comfort - If the NVH gets to you, try lower psi.

I have read, here and there, that high-pressure tires are more likely to kablooie through a pothole. evidence seems to be lacking. Correct me here please.

Click and Clack are our vehicle gods, but they still seem to be behind the curve about center tread wear (for radial tires) under 'over infaltion'. Sad.

If you are serious about tire safety, maintaining (whatever) air pressure is not the whole story by far. You should visually inspect your tires every few k miles, and certainly before any long high-speed flight.

Cousin Tony suggests that exceeding the tire sidewall psi is a personal responsibility decision. I agree.

(edit) Oh just one more thing. The wear bars on your tires are like 1.3 or 2 mm. Wet adhesion decreases rapidly below 4 or 3.5 mm. I would be happy if all my friends driving Prius replaced their tires before the wear bars show. Sorry about the rubber waste, but if your tires don't do what you ask, youse could die.

 

My very first vehicle was a '91 Miata and I overinflated the tires to try and improve fuel economy. The center wear was painfully obvious after 10,000 miles which gives me pause to ever purposely overinflate again.
For safety and liability reasons I maintain psi below max sidewall.

 

When gas goes over the $5.00 per gallon mark
every little bit of gas mileage is going to count.

If you inflate your tires to MAX Sidewall Pressure, usually
44 to 51 PSI, each tires is clearly marked on the sidewall.

Once inflated to MAX Sidewall pressure your tires are still
safe, and you will get a gain in MPG's over the recommended
air pressure from Toyota.

Your ride will be a little harsher perhaps, but its a lot better
than walking the extra distance you will get with the inflated tires.

al

 

J5A, one would want to know if those were radial tires, and how far 'over' you were.

It is clear that xs center tread wear proves that your contact patch has become tiny. Not so safe.

 

I am pretty sure overinflation will DECREASE traction in winter in any car- I do like to overinflate the other 9 months thou