Overinflation - Is there a tire mileage penalty?

[GasSavers_HAHA]

I bought a 1:st gen CRX in 1985 and ran it with around 40 psi all its life. I noticed no uneven wear and the first set of tyres lasted more than 100000 km. I ran the car quite hard at times, especially in corners and curves (since i never brake). While this isn't over-inflation, I have never noticed any drawbacks, other than noise, from running with high pressure.

Since I started reading this forum, I have increased the pressure in both my cars tyres closer to the maximum 45 - 52 psi stated on the tyre. No wear data from this setting yet...

[brucepick]

Please have a look at this:
http://www.officer.com/article/artic...on=19&id=27281

I've added a post on this to the sticky at the top of the general fuel economy forum.

[8307c4]

Maybe I am wrong in this assumption, but I assume over inflation refers to going past the max psi on the tire. Over inflation to me is not about taking it to the max, it's about going beyond that, that is over inflation.

Max. tire pressure as printed on the sidewall is exactly what you want for both mpg, tire life and handling. Ok, so it is a compromise, but it is the best case scenario overall, and if nothing else it eliminates guesswork.

It may be better for mpg to fill past that, but it's no good for tire life or safety.
Perhaps it is safe to go 10% past, but I know it's no good way beyond.

Yes radial tires are better, but we haven't ran bias-ply's in ages and still tires wear uneven at the wrong psi, radials might not show it as fast but show it they will. And radials do balloon when severely over inflated, not sure if lower %'s of over inflation do it, but why guess?

Of course I've worn them uneven due to too low pressures, that's too easy when all it takes is one of those annoying slow air leaks that needs air about once a week, the pressure you know is never quite right, so...

A higher pressure, I've worn a few tires down the center inadvertently because my first F-250 had actual truck tires that took 80 psi and so my next d-250 I wore the tires uneven until I found out those tires were rated 50 psi...

ALWAYS read what is printed on the tire, then fill to that pressure, that's what I learned.
Eliminate the guessing.

As a rule I always inspect my tires for wear about every 5k miles, or at least twice a year.
You know, just something to look at closely from time to time, make sure.
That's it.

[STSinNYC]

I have a close relative who is in the tire business, very knowledgeable. When we got our previous car, and 02 Accord at 30 K miles, he told me to keep the tire at 40PSI (max. cold inflation is 44 on the MXV4+ tires). I did so, rotated the tire every 6-8K miles and ran them our to 70K miles, no noticeable increase in wear in the center vs. the shoulder areas.

I'm doing the same (40 PSI) on our 03 Accord, we have Kumho Solus KH16tires, wear is very good (only 1/32 wear in 12K miles), and it appears to be very even across the tire.

I would not inflate above the max. cold rating on any tire. You're not going to improve rolling resistance enough to warrant the risks.

[palemelanesian]

My last set of tires, I ran them for the lifetime at 35psi. Car asks for 32, tire sidewall 44. They wore down on the edges and not the middle.

From that, I can say that the automaker's specified pressure is TOO LOW. Can't say about sidewall or above, as the new ones only have 7,000 on them. No wear one way or the other yet.

[8307c4]

Max. sidewall is not over inflation, over inflation is above and beyond max.psi sidewall.

For example if max.psi sidewall calls for 45 psi then 60 or 70 or 80 is over inflation, if it calls for 45 on the sidewall then 45 it is, I'm a firm believer that max.psi sidewall is the only correct psi.

Originally Posted by PaleMelanesian

My last set of tires, I ran them for the lifetime at 35psi. Car asks for 32, tire sidewall 44. They wore down on the edges and not the middle.

From that, I can say that the automaker's specified pressure is TOO LOW. Can't say about sidewall or above, as the new ones only have 7,000 on them. No wear one way or the other yet.

I also don't care what the sticker on the door says to me that is too low.

So take what you see, if it wore down the edges on low psi is it not safe to assume if you were to over inflate (past Max sidewall) it would wear down the middle? You guys can test me on this but it's your tire so...
Tires for my car run $100 each, I can't afford it, the savings in mpg are not worth it.
Not to mention if the tire isn't 100% on the road then you have uneven traction, but enough of this

Other notes on uneven wear:
Small chance you may have an alignment or worn suspension component issue, if this wear pattern continues I would recommend having it looked at, but I as well suspect your problem is fixed if you're now maintaining max.psi

Just watch your tires, it is a good idea to look at them once a month or so, just to see if you notice something odd. Minor issues are fine so long they get no worse, but one can prevent oneself a slew of headache with regular monitoring.