[sr71bb]

Originally Posted by cdrptrks

I think higher front tire pressure creates less contact patch and more inside front wear with aggressive camber for street driving. That was my experience when I tried it with -2.8° front camber and 0 front toe. Now I use lower than normal front tire pressure on the street.

Well I have experienced just the opposite using 38-40 PSI I get about 20K miles out of my Michelin 4S on the street using -3.8 front and -2.8 rear camber. I was told to do this by a VERY experienced alignment guy and I took his advice since he certainly knows a hell of a lot more than I do in regards to suspension set ups.

It makes sense when you think about it because IF the tire was PERFECTLY flat (camber was ZERO), then YES; the CENTER of the thread would make more contact with the road surface as inflation pressure increases. BUT, with MORE negative camber, the inside edge would have a tendency to have MORE contact with the road surface than the CENTER of the tire, so the additional tire pressure would counteract that tendency.

Now the REAL reason this all came up was I told DOGHOUSE PERFORMANCE who sets cars up all the time for both track and DD that I DID NOT want to have to change my alignment settings back and forth all the time. He was the VERY first person to tell me that it was DEFINITELY possible to accomplish this if we ran virtually no TOE In or TOE Out. He said THAT was the main culprit of excessive tire wear.

The only compromise I have noticed doing this is that 38-4O PSI pressure in your street tires definitely results in a firmer ride and I have no doubt that I could probably get 5-7K more miles of treadwear on my Michelin 4S street tires if my alignment settings were more conservative but thats all good with me.

[eimarshall]

Originally Posted by khcoaching

Front -3.6 and .08 toe OUT
Rear - 2.7 and .04 toe IN”

Just to clarify Ken, is that 0.08 degrees? Or 0.08 inches?

[sr71bb]

Originally Posted by eimarshall

Just to clarify Ken, is that 0.08 degrees? Or 0.08 inches?

Toe measurements are always expressed in INCHES (technically MM). CAMBER is always expressed in DEGREES.

[khcoaching]

Originally Posted by eimarshall

Just to clarify Ken, is that 0.08 degrees? Or 0.08 inches?

Yes inches. (The actual wanted was 2mm in the front and 1mm in the rear)

[khcoaching]

#13 Ridge Motorsport Park - March 29 2023

Without Chicane 1:45.81

With the weather being so unpredictable, getting any track time this early part of the year has been rough. I was able to score an hour of track time yesterday and took full advantage of it. The car is basically unchanged from the last time I was out in Sept 22' other than:

- New Goodyear 3Rs (19" square)

I have a love hate relationship with the 3Rs. They work really well, but they are a bitch cold and they don't seem all that magically fast. In the interest of keeping this apples to apple, I wanted to see if the aggressive alignment was actually better, hence using the same tires for this test.

- Remote tune

Up to this point, the drivetrain has been 100% stock and now that I am past 2 year of ownership, (still only 45xx miles) I wanted to - do something. I almost pulled the trigger on a complete cam/top end, but could not justify the near 20K to get it done. I settled on a remote tune, by a reputable tuner and went through the multiple steps getting it done. The car did seem to run better, but mainly down low, up to 5000RPM. My expectation was pretty much zero, but I secretly I was hoping for another 2-3mph of top end.

Results!

Temp were high 40s and the track was dry. The bottom line, not the PR day I was hoping for. I suffered from a lack of grip everywhere and the tires really never came in. First run I was 4 seconds off with basically no grip. 2nd run was better, but I had ice mode 2x while trying to run my normal brake markers. 3rd run was the best, but I was ice skating in the middle of the turn and exits. I even lost the rear on downshifts a couple of times.

What's weird was the tires never seemed to get hot, even at 31-32 psi. The rear tires never flexed enough to get to the sidewall and I would certainly lose grip, before the tire flexed. It's also the first time I had to lift in a couple of areas I would be flat a well as well be super conscious of using the brakes as I couldn't get the car stopped. I've run my PR is slightly cooler temps and the track is usually pretty quick this cool.

And....the car was slower. Not by much, but it was slower. It felt good coming off a corner, but it was 2mph down on the top end compared to my PR.

Overall -

I'm done with the 3Rs. Solid tire, but it's not doing it for me anymore. I'm going to sort through the available 19" alternatives as well as get some 18" slicks when I can afford it. The tune deal is weird. I didn't get a chance to log or put the stock tune back in. My tuner is amazing and I am not worried with get it sorted.

Graph #1 - PR vs this outing Blue is March 23'



Pic #1 - Blow up of of Lat G difference



Pic #2 - Front tire sidewall



Pic #3 - Rear tire sidewall




I'll post up a few videos as well.

Ken

[khcoaching]

Here's one of the videos. I did have some weird readings from the Garmin, which I am assuming was from the low GPS reading.

https://youtu.be/XVNxGWHmRMA

[khcoaching]

And in other news, this happened -

2019 ZL1 1LE -

I was lucky enough to have a local car offered to me at a great price. Has some nice upgrades, but also needs some TLC.

[kropscamaro16]

nice upgrade! you going to keep the ss/1le or sell it and only have the zl1 1le?

[khcoaching]

Originally Posted by kropscamaro16

nice upgrade! you going to keep the ss/1le or sell it and only have the zl1 1le?

I'm not sure. The SS is such a great car and I don't plan any further mods with it. If anything, I'll put some of the interior back together and just enjoy it for trackdays. I can't really afford both though, so if someone was interested in it, I would certainly entertain selling it.

The ZLE is actually going back east once I get it all sorted and the goal is to be able to terrorize as many track back east that I can.

Ken

[eimarshall]

WHAT!!?! I really want to see you drive the two back to back!! Lucky dog!


Also with regards to the 3Rs, do you think it was the cold? Maybe cold tire and too much camber? Were they still new new? or had they been heat cycled at all?

[kropscamaro16]

oh nice vir road atlanta etc? any tracks in the usa you havent been to yet that you really wanna hit?

[khcoaching]

Originally Posted by eimarshall

WHAT!!?! I really want to see you drive the two back to back!! Lucky dog!


Also with regards to the 3Rs, do you think it was the cold? Maybe cold tire and too much camber? Were they still new new? or had they been heat cycled at all?

I'll for sure be doing some Ridge days with it once it gets sorted!

They were brand new 3Rs with a late 21' date code. No clue, the last set I did multiple 45 flats on cords.

Ken

[khcoaching]

Originally Posted by kropscamaro16

oh nice vir road atlanta etc? any tracks in the usa you havent been to yet that you really wanna hit?

HA! All of them.

I've been to most on bikes, almost none in cars.

Ken

[kropscamaro16]

damn your lviing the dream im jealous!