Experiment Request: Traction at 50 psi vs 30 psi

[psyshack]

Stopped in and visted with the director of operations at the airport. Looked at the area he is willing to let me use. Now he has to pitch his boss. Since its a city airport that could be the sticking point.

Should know in a few days.

[brucepick]

Good luck with your request to the airport!
I appreciate your efforts.

[psyshack]

I haven't heard anything from the airport. I will contact them next week and see where we are on the request. The director seemed very up beat about it.

[GasSavers_Scott]

The Solstice has 18 X 10's, great tires to race around on, it has factory Goodyear's and so far they have had almost no wear for the last 30,000 miles. The best MPG I got was at 44 psi and got 34 MPG maintained Hwy cruise at 64 MPH. Now this car loves to break loose the rear end in rain, so the comming of winter I aired down to 35 psi and could still get over 30 mpg. With the coming mixed snow and rain and getting stuck on a hill in the snow and having to air down to 20 to climb it, I have been keeping the tires at 25 psi. The result of my MPG has been at cruise of 29 MPG. The ride is softer and the rear hooks to the ground more, the ABS on ice is less jittery than when I ran 35 psi. Hope this helps.

[2000mc]

i think you will find that the answer will vary. and probably due to a number of factors.

and theres another way to look for an answer, just check your tire wear. i try to maintain the highest pressure without causing tire wear problems.

on my 2000 monte carlo with 225/55/17 bfg t/a t tires 44psi would wear the center of the tire faster, 40 was still but not as bad, 35 is where i'm at now. but its 35 with these tires, with snow tires, performance tires, tires with a higher or lower load rating, or a higher or lower speed rating, etc... i might run 30psi, or i might run 50psi.

on my old car, 94 olds 88 w/ 225/60/16 i ran 44 - 50psi always and with a variety of tires, i couldn't wear out tires in the center of the tread to save my life

[psyshack]

I just got permission to include my youngest daughters 04 Camry. It has no ABS. So this should add a dimension to the test that a lot of people can relate to on this site.

I hope the airport comes through! If not I will try to find a another place to do the testing. I want to keep it legal and safe!

[GasSavers_broadwayline]

This seems like a very poor test.

Why don't you buy a G-tech RR and do the test much more accuratly.

http://www.gtechpro.com/

You do know the fastest way to stop is not "skidding the tires" ie, leaving tire marks on the road.

And traction almost always increases with lower psi to a certian level for acceleration, also depending on sidewall type, IE, drag racers almost always lower their tire psi.

Hard sidewall tires this usually does not work as well but still helps.

Also tire psi for cornering traction is extremly dependent on the individual tire and its properties.

[itjstagame]

Seeing the quantification would be nice, but as everyone else said it's clear that higher psi tires are easier to 'break lose'.

Lower psi means higher contact patch and allows for more tire deformation (that is the tire can absorb a bit more power/force and maintain traction by flexing a bit). Now of course this is only dry traction, because with dry traction you want a larger footprint because of the higher contact patch. In wet or snowy driving you may want a smaller contact patch. This is because there will be more force (weight) in a smaller area with the smaller contact patch and will mean it will take more water to hydroplane the smaller contact patch.

I'd like to see the following test in this thread http://www.roclife.org/forums/showthread.php?t=68347 With higher psi than standard as well. I think the trick would be the highest psi without causing excess where in the centerline of the tire.

[GasSavers_scostanz]

I do notice a little less traction with 50# in my tires but I adjust my driving style to account for that.

I just recent replaced my cheap 175/70/13 tires after almost 72,000 miles. About 40,000 of that was at 50#. There was a little more wear in the middle of the tire but it wasn't nearly as bad as I would have expected. If I had rotated the tires more, I may have gotten another 5,000 miles out of them as the rears had a bit more left in them. I'm sold on running a higher pressure.

-- Scott

[JanGeo]

Originally Posted by broadwayline

This seems like a very poor test.

Why don't you buy a G-tech RR and do the test much more accuratly.

http://www.gtechpro.com/

DUH I have an old model of one of those a friend lent me - got to mount it on a level area of the dash and try it sometime now that I have a spare cig lighter power outlet.