Tire wear pattern Options

[wndsrfr]

Check out the pattern of the rubber on my RA1's. I did DE's at VIR, Watkins Glen and Summit point since flipping them mid season, so have about 400 miles on track, 15 heat cycles since flipping. These are the fronts....the rears are much more uniform without a buildup of "worms". The buildup is on the inside edges. I'm guessing that it's indicating that I need more camber but I'm maxed out already. Ideas?
BTW, total mileage on track with these tires since new in March is about 1700 with 61 heat cycles & no sign of cording anywhere yet.

[Woody]

Kind of hard to tell with all the opr buildup. What alignment settings are you running now? Is the tire rolling over on the outside?

[SirAndy]

I'm guessing that it's indicating that I need more camber but I'm maxed out already. Ideas?

No, the exact opposite of that.

Too much negative camber it seems, you're not using the outside of the tire at all ...
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[Matt Romanowski]

To read the tire, you have to do it without the buildup. That means do a lap, at speed, without cool down, and stay on line. Bring it into the pits and stop on pit road to check the tires. As soon as you get the buildup, you can't tell anything.

A 914 with anything other than a crazy motor will not kill tires. We get around 1500 track miles on a set in a race car with a 3.0L motor.

[jhadler]

Just remember the old adage about Toyo race tires...

"Toyo tires, they suck for a really long time".

With that many heat cycles, that many miles, and having flipped them once in the middle of all that, the only thing I can reliably comment about the apparent "wear" pattern on those tires is that they're most likely rocks by now. Drawing any other conclusion from the picture you included would be a fool's errand.

Sure, you've got more apparent wear on the "inner" edge (OPR not withstanding). But that could be the result of many different things. Unreliably, I'd offer the following possible explanations:

One) With the majority of the mileage logged before you flipped them, this is the most likely scenario. You already wore down that "inner" edge when it was on the outside, when the tires were newer and softer. And now that they've turned to rocks, you'll never even them out.

Two) Too much negative camber - not generally something the 914 is often accused of.

Three) Too much toe - a possibility, especially if you haven't actually taken a look at the alignment settings in a while, or ever. (bad bushings have a way of doing that).

Four) Sadly, another possible explanation (but unreliable) here is that you've got plenty of negative camber, but you're just not pushing the car hard enough.

If you really want to get a quick and dirty idea. Run a hot lap, stay off the marbles, stop (don't flatspot 'em) in the hot pits and measure tire temps right then and there. That will tell you VOLUMES more than the above picture. Even a temp test by a bare hand will at least tell you if you have gross alignment problems. Better yet, find someone there at the event that has a pyrometer to get good accurate readings.

[brant]

coat them with some race tire softner....
let them sit over night and go wear them out

you guys are crazy..
I run Hoosier A's on the road course.
I thought I was doubling the expected life-span at 30 heat cycles

brant

[wndsrfr]

OK, Just measured the camber.....3/4" on a 16" rim gives 2.7 degrees negative camber. I'm inclined to go with Andy's assessment of too much camber along with my skill level not likely pushing the car hard enough also. I mean, something like 1000 miles and no spins....gotta turn up the heat, eh?
So, I'll back off the camber a bit, swap the backs to the front and see what I get at Roebling next month. Bob Woodman has a track day there ahead of the Florida Crown DE & I should be able to get temperature readings from his crew to figure out the setup. I'm sure he'll take one look and then sell me a new set of tires before it's all over.....
Any input on the camber to shoot for on road courses other than the "max it out" adage?

[Woody]

OK, Just measured the camber.....3/4" on a 16" rim gives 2.7 degrees negative camber. I'm inclined to go with Andy's assessment of too much camber along with my skill level not likely pushing the car hard enough also. I mean, something like 1000 miles and no spins....gotta turn up the heat, eh?
So, I'll back off the camber a bit, swap the backs to the front and see what I get at Roebling next month. Bob Woodman has a track day there ahead of the Florida Crown DE & I should be able to get temperature readings from his crew to figure out the setup. I'm sure he'll take one look and then sell me a new set of tires before it's all over.....
Any input on the camber to shoot for on road courses other than the "max it out" adage?

You really need to be taking tire temps at this point.

[Randal]

OK, Just measured the camber.....3/4" on a 16" rim gives 2.7 degrees negative camber. I'm inclined to go with Andy's assessment of too much camber along with my skill level not likely pushing the car hard enough also. I mean, something like 1000 miles and no spins....gotta turn up the heat, eh?
So, I'll back off the camber a bit, swap the backs to the front and see what I get at Roebling next month. Bob Woodman has a track day there ahead of the Florida Crown DE & I should be able to get temperature readings from his crew to figure out the setup. I'm sure he'll take one look and then sell me a new set of tires before it's all over.....
Any input on the camber to shoot for on road courses other than the "max it out" adage?

You really need to be taking tire temps at this point.

+1

They will tell you exactly what is going on.

Didn't you do this when you took the car out the first time with new tires?

What does your corner balance look like?

Any stiffing in the chassis as yet?

[SirAndy]

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Tire temps will tell you a lot.

If it were me, i'd back off the front to about -1.5 deg negative and then get some tire temps.
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[ChrisFoley]

All that pickup (buildup) on the inside of the tire is from the cool down lap.
With a lot of negative camber the outside edge of the tire hardly touches the road when you're going slowly around corners, so only the inside half gets the marbles smeared onto it.

In addition to the wear bars in the circumferential grooves there's a series of tread depth holes on the tread surface.
You need to compare the depth of the inside ones vs the outside ones to get an accurate measure of tire wear across the surface.

I would back off to 2 deg. negative at the front and 2.4 deg. at the rear.

[jhadler]

Just curious. Does this car have suspension or chassis mods to get you that claimed 2.7 degrees of negative camber? That seems like a lot of negative camber for a stock configuration.

-Josh

[wndsrfr]

Just curious. Does this car have suspension or chassis mods to get you that claimed 2.7 degrees of negative camber? That seems like a lot of negative camber for a stock configuration.

-Josh

Here's a shot of the drivers side front suspension tower.....you can see it has a aftermarket monoball I think it is....also where the cage is tied in to the tower.

Also, to answer Randal's question....yes, there's good stiffening from rear consoles and towers to the cage.

The corner balance 155# driver is:

LF 502 444 RF

LR 648 577 RR

1079 1092 Cross