Boomer111

First off my initial depth testing was done with 3,225 miles driven on a new set of S0-4 Pole Positions. They came with 10/32 tread depth, not measured by me but are the listed specs.

Tire psi was 30-32 HOT. the cold pressure was between 27-28 psi.

I will not complicate this with all the depth readings either before or after my pressure change.

Now 2,200 miles later after running 34-35 HOT my readings look like this.

LF and RF and RR read all the same as previously except for the second rib in and each showed 1/32 more wear. This was the only variation between these three tires.

I took 4 reading across each tire using each rib.

The LR showed 1/32 more wear on ribs 2,3,and 4. This is reading from outside to inner. The outer rib remained unchanged.

I know this isn't many miles to compare and it still took me 8 months just to drive the 2,200 miles.

My reads as follows:

-.08* -.08* L-R front camber

7.9* 8.0* L-R front caster

.05* .05* L-R front toe


-.05* -.05* L-R rear camber

-.02* -.01* L-R rear toe

I am a little concerned with the front toe, I would like to see it like the rear.

I lied sorry, here are the 32nd reading across all 4 ribs showing the tire tread depth.

First reading with 3,225 miles:

LF 7,9,9,8. RF 7,9,9,8. again in 32nds.

LR 7,8,9,8. RR 7,8,9,8. " "

Now the latest readings after 2,200 miles and increase of approx 3 lbs psi. to 30 cold or 34 HOT.

LF 7,(8),9,8. RF 7,(8),9,8.

LR 7,(7),(8),(7). RR 7,(7),9,8.

( ) equal a change from initial depth reading after the first 3,225 miles.. When reading the gauge I rounded off to the nearest 32nd so this could be the anomaly in the LR readings being different....OR ?

Seeing as how the outer depth across all 4 tires did not change I think the increase psi helped here but ti might have taken some tread on the 2nd rib in. on all 4 tires.

The LR just has me puzzled.

I plan on keeping the tires at 30 psi cold for another year. I do adjust all year around as the outside temps fluctuate.

Any thoughts?

I think the initial low psi caused some accelerated wear on the outside with hard corning. I drive aggressively in the turns but do not put down rubber accelerating. I do exhibit the occasional romp through a couple of gears. I have 4:10 diff. and have a tune and Z06 manifold system.

SUB VETTE

What are you trying to prove? That higher tire pressures lead to less wear?? or??

AORoads

It does appear that the lower initial pressure may have caused more wear. Tires, pressure, suspension, etc. are always a compromise between factors like handling, noise, tire life, stopping, ride quality, etc.

Boomer111

Not trying to prove anything.

I was using Evil Twins suggestion of running 30 Hot.

Changed to 30 cold.

I was interested in any difference in wear.

I do think the lower pressure wore the edge more while cornering though.

I also think the LR wear is attributed to bottoming out and contact with the liner. This is another matter though.

Bill Dearborn

Not sure what your initial readings were, however, here are a couple of things to think about. The negative camber setting will move the center of the tread touching the road thus the wear point inward. The .05 toe in will tend to move the wear point toward the outside of the tire. Hopefully, that would tend to cancel out the impact of the negative camber. If you get a probe type tire temperature gauge (not IR) you can use it to measure across the tire to see where the temp high points are located. The high points indicate the spots where the tire is working harder. Take 3 readings across the tread of the tire. One at the outer edge, one in the center and one at the inner edge. If the two outers are higher than the center you have too low of an air pressure. If the center is higher than the outside then you have too much. If the inside edge is higher then you may have too much negative camber or too much toe out. If the outside edge is higher then there is may be too much positive camber or too much toe in. To get a good street temperature reading take the car out for a 20 or 30 minute 50 or 60 mph drive with few if any stops.

When you have driven enough to get the tire temps up. Quickly pull off the road and starting with the one of the front tires quickly take the three measurements across the tread of each tire. You only have a minute or so before the surface temp of the tires starts to cool so you need to move fast. Once you get everything recorded you may be able to see what if anything needs to be corrected.

Bill

Boomer111

Thanks Bill I am just to cheap to buy a temp probe. I looked into it already. No track time so I figured the depth gauge over some time would have to suffice.

So you would recommended leaving the front toe as is?

mikeCsix

Bill,
Can you suggest a brand of probe type tire temp gauge? I screwed up and bought an IR version.

mikeCsix

Bill,
Can you suggest a brand of probe type tire temp gauge? I screwed up and bought an IR version.