Tire OVERinflation...it really works!!!

[krousdb]

Well if you go read the articles linked earlier in this thread, you will see that there is conflicting data. You could argue either way I guess. But the last two sets of tires on the Prius were inflated to 60 PSI. Each set of OEM Goodyear Integritys lasted 37k miles, about 5-10k longer than is what is typically reported. Both sets of tires, at the time of dismounting showed perfectly even wear.

[diamondlarry]

Originally Posted by onegammyleg

Hi krousdb

So , are you saying that these multibillion $ tyre manufactures dont know what they are making , or are they just lying ,

I don't know if they are lying or not but, they used to say that you couldn't use a tire on the left side of a car that had been on the right side and vice-versa. This was said about all tires, not just the directional treads. After that myth was disproved you started seeing the recomendation of the diagonal rotation pattern you see now.

[SVOboy]

I'm not going to get into the argument over whether cops who trust their lives to a solid tire or companies who do nothing but spew crap to make more money have different amounts of validity to their arguments, but I will say that hot georgia should introduce his or herself to the forum so we know all know who he or she is,

[krousdb]

Yes, ride quality definately suffers. Over a year ago I did some testing on the Prius marathon course with the Prius. At 35 PSI, 96MPG. At 50 PSI, 97 MPG and at 60 PSI, 98 MPG. Those gains are quite small but may be worth it to some drivers. The ride quality really suffers between 50 and 60 so 50 seems to be a good compromise.

[psyshack]

Ive ran my tires at max side wall psi for years. I always get good tire wear and milage. I got 57k miles out of the Rangers OEM AT Wilderness self changing recall tires. I chose to keep mine. Then I put a cheapy set of Dougles Wal-Mart tires on it and got over 50k miles again out of them. So i put another set of heap cheap tires on it and doubt I'll ever purchase tires for it again.

Its looking like the OEM tires on the Hondas will make 40k pretty easy then be changed out for LLR tires and again be set at max side wall.

I prefer the ride of my cars to be on the firm side.

Im not a fan of inflation above max side wall psi. I dont like the way cars handel when psi is pushed way up there. Except for when auto -xing on very smooth surfaces. It helps with rolling the bead off the rim if you get hooked up real good.

Other wise the rear ends seem to get loose as a goose on me at certin times. Like when on a clover leaf on ramp with bad expansion joints. There comes a point when suspension cant react as fast as a small amount of side wall flex. Resulting in the rear end wanting to kick out on me at every joint.

That reminds me ,,,, I need to check my psi this am.

[onegammyleg]

Hi all..

One point that hasnt been touched on much is the handling degradation due to over pressure.(and no , ime talking about over 60psi - not 35)

The tyre manufacturer knows the saftey limits of the carcase (tyre structure) as far as air presure is concerned , and I would guess that this is A LOT higher than what is printed on the sidewall.

I would not be worried about tyre failure from presures in the mid to high 40's at all.
I think its quite safe.

But even at these presures handling and braking probably are compromised.

When racing we use tyre pyometers to measure the temperatures of the tread at different points.
Assuming 0 degree camber and 0 toe setting a tyre that is overpresurised will show higher temps in the centre of the tread.
A racer knowing this will liklely drop the pressure to the area where the tread has equal temperature across the face.
This will be in the zone of maximum grip.(suspension setup and steering angle complicate this , but this is a simple explanation)

If tested with a pyrometer normal road tyres can show overinflation but its less of a problem (structually) for them as they (by comparison to race tyres) are not so fragile.
They are quite duarble but low performing as far as tyres go.

But really , if you notice that in the wet you are more likely to plow through a corner than turn it when using higher presures then really it is already too high.
This is easily tested and doing it in the wet simulate what its behaviour would be in the dry but at a much lower (and safer) speed.

As ive said b4 , ime all for saving gas and money , but when the line of safety gets crossed I dont see any saved value at all.
I think my safety and the saftey of my friends and strangers is more important than the few extra cents in my pocket.

My presures are around the low 40's where I feel that its a good safe compromise.



PS :theres been some good posts so far on this thread - Thanks

[Hot Georgia]

SVOboy wrote:

I will say that hot georgia should introduce his or herself to the forum so we know all know who he or she is

Thanks. Here is more than you'll care to know:
http://www.gassavers.org/showthread....6185#post26185

[SVOboy]

Well f0rks, it's in the wrong forum!

[philmcneal]

i like to deal with tire pressure the lazy way, set them real high and don't have to check with them for a long long time! I think its been two months since I checked my pressure but before I did I set every tire above 60 psi, so by the time I check them they should be around 40 and that's when its time to pump them up again!