LOL! Good comments
Quote:
Quote:
Quote:
Okay, we can disagree on exceeding side wall "max pressure." I prefer to believe that the engineers that set "max pressure" really meant it. Quote:
Quote:
Quote:
Ernie Rogers |
Quote:
Ernie Rogers |
I use 40 psi
Quote:
|
Quote:
|
Quote:
I have to say, for my own car I've settled at a very similar practice to your decision. My oem is 27 with optional increase to 32 for better FE, my sidewall 44, my tires are at 40ish. Please don't guess that loading up your car/truck will stress highly pressurized tires. It's the other way around. Increasing tire pressure raises a tire's load capacity, up to the tire's sidewall rating. So, at least according to the published information, running at less than max sidewall gets you less than rated capacity and increasing beyond that point gets you no additional gain. You can find a lot of this at tirerack.com if you dig for it. I'm putting in another plug for the reference quoted earlier in this thread: https://www.officer.com/article/artic...on=19&id=27281 Long story short, they put Crown Vic police cruiser tires (44 psi rated) + wheels on a Ford Ranger p/u and pumped them up to 100 psi. Then gave it to a race driver to do some stunts with. Success. The tires hold up far better at 100 psi than they do at 44. There is quite a lot of additional information in the article on the topics of safety, handling and reliability of tires at different pressures. Draw your own conclusions, but please do read the article. I'm not recommending running 44 psi tires at 100 psi for street/highway use. However I'd certainly consider the max sidewall to be allowable, and 10-20% more to be doable. In actual practice, 40 psi feels pretty hard in my car so I'm not inclined to go much higher. But that's my car and my tush. As usual, ymmv and I suppose ytmv also. |
Quote:
So I did a quick search... and found a patent for bias ply tires... It makes a reference that says the steel cord safety factor should range between 4 and 11, 7 being a target. Now that's not directly related to inflation pressure - but should be related to hoop stress (P*D/2).... Again, this isn't really an equivalent - and I don't know if the mentioned factor of safety applies to traditional radially belted tires... Really, I doubt I'll find the actual number anywhere as it's probably trade secret. ---- Quote:
Quote:
I am also thinking of a case of a tire with wheel run out (out of round). So we basically have a tire in the shape of an ellipse (a very minute one though). The areas with the shorter sidewall will have more stiffness and translate that into the the vehicle suspension - as compared to the higher sidewall. So that, combined with the assumption that the normal force is constant leads me to the difference in taller versus shorter sidewall is the k. Thus the deflection for the stiffer (shorter sidewall) should be less than the taller sidewall... So that paragraph above would mean that sidewall stiffness AND inflation pressure are variables that determine contact patch size (something tells me stiffness from the tire is much less than inflation stiffness) Of course, this could be *** backwards - and x is constant and the force changes (although, intuitively - that seems wrong or I am missing a key point). In any case, it doesn't matter for me either way. I have no intention to get a shorter sidewall :p I just like this sort of discussion :p |
Quote:
1) max sidewall is spec'd for cold pressure, meaning cool morning temps before driving the car. and 2) max sidewall and also the mfg oe recommedations allow for increases in outside air temp during the day as well as increase in tire temperature from driving. So, check tires when cold. Drive with confidence after that. |
I wouldn't run your tires way too much over what the side wall states.
Over inflating your tires will wear out the center. If you think about it, it will also give you less contact patch to the ground, that is one reason why you are getting lower rolling resistance and getting better mileage. But you pay for it at the end with premature tire wear. Something to keep in mind. You get short term benefits of better gas mileage at the expense of your tires. Gary |
Overinflating is not really a cause of premature wear, low pressure is the major cause of that.
It may affect wet handling adversely, so practice. Dry handling effects are good, the sidewalls are nice and stiff and do not flex as much in the corners (them guys that drive on two wheels use like 100 psi). Them steel belts keep things lined up pretty well so there's no appreciable bulging from overinflating. |
Low Profile Tires on a larger diameter rim for the same or bigger tire diameter won't hurt mileage ( I know you meant on the same sized rim but it could cause confusion).
There is a point where rolling resistance will increase with tire pressure...if the tire is set so high it stops conforming with the road surface, it can be detrimental. Tires do grow convex and/or convex with different psi's. This will happen in the middle of a tire and causes different running temps along the inside, middle and outside edges of a tire...you really want pretty even tire temps for best results. No reason to get uneven wear on tires and then all the money you saved on fuel goes to new tires. Agreed that low psi's are much worse, so err on the side of high psi's. |
All times are GMT -8. The time now is 07:30 PM. |
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.