15 more PSI = 7% better MPG

[gone7]

Originally Posted by mcrews

hummmmm.........
must be the really new & expensive cars that have that button......
We are talking factual reality here....what are you talking about.?

LOL!

Qute, but not applicable. This forum in all of its threads appears to contain any possible idea anyone has for increasing fuel economy.

That said, exactly what do you think would happen if someone adds fairings and other parts to their vehicle? Did you think it would get lighter?

Why wouldn't a person take off parts and eliminate extra passenger space if that person was the only one riding in the car? Wouldn't that be more energy efficient?

That's kind of a "Duh", IMHO.

[Joggernot]

I have had tires wear the center tread. 1982 Honda Accord with Michelin tires (first set after OEM). Haven't had the problem since, but I've never had Michelin tires again.

[cbaber]

Originally Posted by ACEV

The bottom line is to try and see. It is a free country. You can do as you like. But let us know the results after that 65,000 mile warranty runs out. Until then, it is all conjecture.

This shouldn't even be a debate on ecomodders. We have so many veteran members who have proven that over inflation does not cause uneven wear, when the tires are otherwise properly maintained.

It's easier to believe their claims because all the planets have to be aligned to not experience wear. Meaning proper tire maintenance was followed. It's not as easy to believe someone that says they experienced center tire wear from over inflation, because of all the variables involved that could have caused the wear. With that in mind, the overwhelming majority of ecomodders report success with over inflation.

Consulting tire manufacturers for information is interesting. I read somewhere that over inflating your tires can wear your suspension faster because of the increased stiffness. That's a very bold claim, considering all the variables that could contribute to suspension wear. For example, how fat are your friends, the road quality in your area, climate, driving style, etc. The information they put out isn't exactly science.

[California98Civic]

Originally Posted by ACEV

I'm always amazed at those who will not even take the time to search the same Internet they problably have access to 24/7. In just a few minutes I found:

With such an imperious opening, I expected a great set of data, which would have been welcome and fun.

Originally Posted by ACEV

Experts:
More About Larry Carley:
Tire Industry Association | Tire Industry Association
http://www.tirerack.com/tires/tirete....jsp?techid=72
Tips to controlling inflation pressure

There is no data in these links and they're hardly relevant to this thread on tire wear. One link is a profile of "Larry" and another is about HIGH speed driving and psi--not wear--while a third is an industry association site's generic main page and the fourth is a goofy and ancient site called "tire world information" that offers no data.

No there, there, despite the dramatic flourish.

[gone7]

With such an imperious opening, I expected a great set of data, which would have been welcome and fun.

Hardly. Do your own research.

There is no data in these links and they're hardly relevant to this thread on tire wear. One link is a profile of "Larry" and another is about HIGH speed driving and psi--not wear--while a third is an industry association site's generic main page and the fourth is a goofy and ancient site called "tire world information" that offers no data.

No there, there, despite the dramatic flourish.

Should have dug deeper.....

I spoke with Marvin Bozarth, Senior Technical Consultant for TIA, and he agreed with my assessment. Of course he only has over fifty years experience. In particular, while he minimized the tire wear pattern found in overinflation since the advent of radials, he made clear that vibration was a predominant problem with overinflation. It is not something that most people will ever notice because they associate part failure with the part and not the real cause from the abuse of vibration damage. The whole car wears a great deal more with overinflation rather than sticking with factory specs. The high cost of that damage to the car must certainly out-weigh any supposed savings in fuel.

He also said that he has seen very little difference in fuel economy when overinflating. While some may overinflate by 2 or 3 or 4 pounds for heavier loads, wet pavement issues and impact damages become significant.

Now, go do your own homework.

And remember, while trying to save a few bucks on fuel may be admirable, the real fundamental issue is that cars must be designed from the ground up for the purpose desired, as I implied before.

[cbaber]

Originally Posted by ACEV

He also said that he has seen very little difference in fuel economy when overinflating. While some may overinflate by 2 or 3 or 4 pounds for heavier loads, wet pavement issues and impact damages become significant.

Now, go do your own homework.

And remember, while trying to save a few bucks on fuel may be admirable, the real fundamental issue is that cars must be designed from the ground up for the purpose desired, as I implied before.

Did you not read the whole point of this thread? Going from the factory spec of 30 PSI to the maximum sidewall pressure of 45 PSI I gained 7%. That is my own personal experience and many, many, many others have had the same result or even better. That isn't even over inflating, so there is still more to gain if I decide to over inflate the tires.

Clearly, your conversation with Marvin confirmed the fact that center wear on radial tires because of high pressures is a myth. But the vibration issue really struck me as odd. Tire/wheel vibrations happen when tires are not properly balanced. I don't see how increased pressure would create a vibration, unless the quality of the tire allowed it to deform under stress. Now, the entire point of the thread was to discuss if over inflating beyond the indicated sidewall pressure could have these results.

If you have a tire that deforms at 60 PSI, it's probably the worst quality tire in the world. As many have advised me in this thread already, modern tires are capable of handling more than their indicated max pressure.

[mcrews]

Originally Posted by ACEV

LOL!

Qute, but not applicable. This forum in all of its threads appears to contain any possible idea anyone has for increasing fuel economy.

That said, exactly what do you think would happen if someone adds fairings and other parts to their vehicle? Did you think it would get lighter?

Why wouldn't a person take off parts and eliminate extra passenger space if that person was the only one riding in the car? Wouldn't that be more energy efficient?

That's kind of a "Duh", IMHO.

Especially since members are already removing seat etc. duuhh

[niky]

Originally Posted by California98Civic

another is about HIGH speed driving and psi--not wear--

Not to mention the fact that it points out that higher pressure is necessary at higher speeds.

Originally Posted by ACEV

vibration was a predominant problem with overinflation.

Originally Posted by ACEV

The whole car wears a great deal more with overinflation rather than sticking with factory specs. The high cost of that damage to the car must certainly out-weigh any supposed savings in fuel.

Have you ever dealt with vibration damage? I have. What it equates to is changing your suspension bushings maybe a few hundred kilometers earlier (like 120,000 kms instead of 125,000) and tightening your body bolts.

One should note that modern cars are built for stiffer tires (as reflected in the higher door sticker pressures indicated versus older cars), and suspension design nowadays takes into account stiffer tire carcasses and higher inflation pressures.

Originally Posted by ACEV

He also said that he has seen very little difference in fuel economy when overinflating. While some may overinflate by 2 or 3 or 4 pounds for heavier loads, wet pavement issues and impact damages become significant.

Wet issues... so-so. Actually... it's dry performance that suffers, particularly in terms of braking. Hydroplaning lessens at higher pressure.

-

There is no doubt that running very high pressures is bad for the suspension and if you run them high enough, the tire will experience greater wear. But there is no universal "too high" pressure. Some tires run fine over maximum sidewall. Some run crappy and experience center tread wear even below maximum sidewalll, even if you run them at the "proper" door pressures.

All tire carcasses will happily accept higher than maximum sidewall... though again, as some of us have pointed out, the diminishing returns beyond a certain inflation pressure (again, there is no universal pressure at which this happens) mean that you have to experiment to find the best compromise.

[RedDevil]

Originally Posted by Joggernot

I have had tires wear the center tread. 1982 Honda Accord with Michelin tires (first set after OEM). Haven't had the problem since, but I've never had Michelin tires again.

I had a '85 Civic that ate itself though the OEM tires and a set of Vredesteins, but did over 80,000 km (50,000 miles) on a set of Michelin Energy tires; the rears actually lasted another 40.000 km. Needless to say, I have used several Michelin sets since then. Always grippy, always better FE than the other brand tires that came off whatever car it was, and always lasting well.

On my Nissan Almera I experienced some cupping on the outer thread edge, but that was probably some alignment issue. Swapped the tires left and right, raised the pressure a bit, problem solved.
Other than that, Michelin never let me down.
(running the OEM Bridgestone summer and (now stored) Continental winter tires on my Insight )

[CapriRacer]

Originally Posted by cbaber

......Clearly, your conversation with Marvin confirmed the fact that center wear on radial tires because of high pressures is a myth.......

Using inflation pressures higher then what is listed on the vehicle tire placard: 5 years ago I started cataloging all the issues I found posted on the internet as I came across them. I now have over 4 pages of links just on uneven wear. I also have lots links to other issues as well.

Yes, those would be anecdotal, but so is much of the positive information. Yes, it isn't always clear what pressure is being used - whether you could sort it out as "above placard", or "above Sidewall max" or whatever.
But all these links are at the same level of "anecdotal-ness" (Look, I invented a new word!) as the OP.

I wasn't interested in single cases. I was looking for trends, big picture, repeated reports of the same phenomenon.

Besides, knowing how inflation pressure affects the shape of tires is what I do - and more inflation = rounder tread radius is the way the science works.

So, No, it isn't a myth.

BUT - it is clear that there is more going on that JUST inflation pressure. It is being clouded by other things that also have affects. In other words, while inflation pressure has an affect, it can be negated by other factors - so sometimes the tires will wear evenly, and sometimes not. That's why there is conflicting information and confusion.