[clyde]

Originally Posted by sab123

I went to an alignment shop, and they say that all they could get is -1.2 on on side and -1.3 on the other. They say they've disengaged the spline bolts, and also took out the bolts, had a look at them, and found them round, not cam-shaped. So I don't understand, is there some trick to getting to -2 degrees?


I wonder if maybe you can get more negative camber by getting the wheel in the air and pushing on it, or something like that?

The bolts are round, but the holes they go through are not...especially the top one. You loosen them both so the splines disengage and if push the strut inward (towards the engine), the knuckle will rotate on the axis of the lower bolt. The top of the knuckle will move in a bit. If you maximize that movement and tighten the bolts when they're as far inward as possible, you'll get the camber.

Pic below is of my turbo (no pics when I did my 1LE), but the 1LE basically looks the same and it works the same way. See all the extra space around the top bolt? It's being pushed inward in the photo, so you can see the free space on the near side of the bolt. When tightened, there will be some space between the edge of the nut and the witness mark on the strut (left side in photo). That's where the extra camber is.

[sr71bb]

Originally Posted by cdrptrks

I tried this to stretch tire life on the stock SC3 tires that already had worn front inside edges and they corded in 500 miles of highway driving (with -2.8° front camber and 0° front toe). I could feel a big heat difference on the inside of the tire compared to the rest. Now I use 28psi cold which I believe allows a bigger front contact patch that causes less excess heat/wear on the inside front edges.

Well I was told that more PSI will increase the contact patch on the CENTER of the tire which would offset to a degree the increased contact that the tires have on the inside edges that you get with increased camber settings.

I didnt really believe that myself intially but I tried it and it does work.

[cdrptrks]

Originally Posted by sr71bb

Well I was told that more PSI will increase the contact patch on the CENTER of the tire which would offset to a degree the increased contact that the tires have on the inside edges that you get with increased camber settings.

That makes sense if the tire has 0 camber but with significant negative front camber I believe more pressure reduces the overall contact patch by lifting the outside half of the tire away from the pavement more causing more loading/weight/heat/wear on the inside.

[WhiteMale]

NVM

[sr71bb]

Originally Posted by cdrptrks

That makes sense if the tire has 0 camber but with significant negative front camber I believe more pressure reduces the overall contact patch by lifting the outside half of the tire away from the pavement more causing more loading/weight/heat/wear on the inside.

Well here's the deal. I got approx. 15K miles on my MS4S 305 30 19 street tires using the specs I posted above and at 30PSI street pressure which is pretty close to the 28PSI you mentioned. PLUS I am running much more camber than most people for sure.

WITH NO OTHER Changes, I ran 38PSI and got close to 20K miles on THAT set. So we can talk about theory all day long but in reality more pressure worked for me and I did that following the advice of ADAM at DOGHOUSE Performance at Motorsports Ranch track in Cresson Texas.

He convinced me against my will that we could run track alignment specs on the street and fare pretty well as far as premature wear goes as long as TOE IN TOE OUT figures were not too aggressive (more towards NEUTRAL).

And ANOTHER thing ADAM told me which I thought was BS as well relates the the relative height of the REAR END. Since I have adjustible coils I toyed with the idea that lowering the car an inch or so in the back would help hook up the rear end a little better.

Adam explained to me that just the opposite was true and he was right. Our cars like a downward rake towards the front of the car and if you try to level that out handling will suffer.

[cdrptrks]

Originally Posted by sr71bb

So we can talk about theory all day long but in reality more pressure worked for me

As I mentioned previously, first I tried higher pressure than recommended on the door sticker and corded the inside front edges prematurely while on a long highway trip at -2.8 front camber with 0 front toe.

Since then I changed to running lower pressure than recommended on the door sticker on the street and have not had such premature inside cording even though I did over 2k highway miles driving between different tracks on each of the last 2 sets of tires (in addition to driving on the same tires on track). I was using Goodyear Supercar 3 tires rather than your PS4S. Maybe stiffer sidewalls on the SC3 account for our different experiences.

[VR Baron]

Originally Posted by cdrptrks

As I mentioned previously, first I tried higher pressure than recommended on the door sticker and corded the inside front edges prematurely while on a long highway trip at -2.8 front camber with 0 front toe.

Since then I changed to running lower pressure than recommended on the door sticker on the street and have not had such premature inside cording even though I did over 2k highway miles driving between different tracks on each of the last 2 sets of tires (in addition to driving on the same tires on track). I was using Goodyear Supercar 3 tires rather than your PS4S. Maybe stiffer sidewalls on the SC3 account for our different experiences.

I run -2.8 front, -1,8 rear. Toe has been 0 to .125 out in front. Goodyear sc3s for street use( original tires). 11500 miles on them highway/ city, mostly highway. Even wear across the tires at stock 32 cold psi. 19” race tires all had even wear at 32/36 psi as well.

[Dirtbike]

FYI there is really no need to knock the bolts out exposing the splines. I happened to have my wheels off so I took a short video to explain.

https://youtube.com/shorts/vYGwaJHCA...3xVP1ALXD-lDyC

It will move to its min/max values without exposing them.
Easiest thing to do is loosen both nuts, set the car back down with the wheels back on (on the alignment rack). The weight of the car will push the camber negative as far as it mechanically can go. Then use the threaded bolt hole at the top of the hub (install the GM adjustment bolt, or whatever M8? you have handy) to adjust back positive where you want it, tighten the nuts back down. Then set your toe and torque everything down. Hope that makes sense.

[cdrptrks]

Originally Posted by Dirtbike

FYI there is really no need to knock the bolts out exposing the splines. I happened to have my wheels off so I took a short video to explain.

https://youtube.com/shorts/vYGwaJHCA...3xVP1ALXD-lDyC

It will move to its min/max values without exposing them.
Easiest thing to do is loosen both nuts, set the car back down with the wheels back on (on the alignment rack). The weight of the car will push the camber negative as far as it mechanically can go. Then use the threaded bolt hole at the top of the hub (install the GM adjustment bolt, or whatever M8? you have handy) to adjust back positive where you want it, tighten the nuts back down. Then set your toe and torque everything down. Hope that makes sense.

This is incorrect. I have tried it myself in my driveway and closely watched a tech try it on an alignment rack. Yes there's some adjustment range without disengaging the splines but it can mechanically go farther with the splines disengaged. There's still a gap between the back of the knuckle and the strut when you don't disengage the splines so the camber is not mechanically maxed out. -1.8 vs. -2.7 is about the difference on a typical Camaro.

Also it is not necessary to lift the car before loosening the nuts if you have enough room underneath to do it like when the car is on an alignment rack.

[sr71bb]

Originally Posted by cdrptrks

As I mentioned previously, first I tried higher pressure than recommended on the door sticker and corded the inside front edges prematurely while on a long highway trip at -2.8 front camber with 0 front toe.

Since then I changed to running lower pressure than recommended on the door sticker on the street and have not had such premature inside cording even though I did over 2k highway miles driving between different tracks on each of the last 2 sets of tires (in addition to driving on the same tires on track). I was using Goodyear Supercar 3 tires rather than your PS4S. Maybe stiffer sidewalls on the SC3 account for our different experiences.

I think you are on to something with the differences in sidewall stiffness. That may very well be the difference in results.

[VR Baron]

Originally Posted by sr71bb

I think you are on to something with the differences in sidewall stiffness. That may very well be the difference in results.

Makes sense. And like with the old Re71R’s with their stiff sidewalls they could use less camber and around 31 hot psi. At least for autocross. For autocross MP4’s, falcons and nankangs seem to like 35/36 hot psi and the new re71rs like I run like 33/34 psi. Unless you are heavily modded with a lot of camber and wider tires etc, then lower psi can be used. All depends on setup, course etc.

[Dirtbike]

Originally Posted by cdrptrks

This is incorrect. I have tried it myself in my driveway and closely watched a tech try it on an alignment rack. Yes there's some adjustment range without disengaging the splines but it can mechanically go farther with the splines disengaged. There's still a gap between the back of the knuckle and the strut when you don't disengage the splines so the camber is not mechanically maxed out. -1.8 vs. -2.7 is about the difference on a typical Camaro.

It's not incorrect..... But we'll agree to disagree. I'm not sure what you did in your driveway, but here is my test method:

The splines engage the aluminum knuckle, not the strut body/slots. You can free spin the splined OD of the bolts inside the strut slot with the knuckle removed. If there is any question (see video below). You are mechanically limited by the OD of these splines against the strut slots max L and R. The only other thing that might be mechanically limiting is if the contact face of your bolt may be hitting some deform or burr on the strut contact point. At the very least you may want to give it one small tap to create a tiny gap, but from what I've found on several Camaros so far - it's unnecessary. Definitely No need to expose the whole splined portion.

https://youtube.com/shorts/co6n3Nhm6...lfKklLVTepvOzb

I thought maybe I was mistaken, so I did this 3x times to confirm on an alignment rack this afternoon:

1. Loosened the nuts top/bottom, moved to max position, tightened down
2. Completely disengaged splines, moved to max position, tightened down

Once the bolts are tightened back down, anything you may gain with the splines/taper exposed will be removed once reengaged/pulled in.

Final results were exactly the same in both cases.
Top: 22.38mm from the face of the knuckle (using gm adjustment bolt hole with micrometer) to the back of the strut. See pic.

Then final camber using a Hunter laser alignment rack showed both methods were exactly the same.

Originally Posted by cdrptrks

Also it is not necessary to lift the car before loosening the nuts if you have enough room underneath to do it like when the car is on an alignment rack.

I never said it was.
I just prefer to final torque & mark mine with the wheels off.

[sab123]

Originally Posted by sab123

I went to an alignment shop, and they say that all they could get is -1.2 on on side and -1.3 on the other. They say they've disengaged the spline bolts, and also took out the bolts, had a look at them, and found them round, not cam-shaped. So I don't understand, is there some trick to getting to -2 degrees?


I wonder if maybe you can get more negative camber by getting the wheel in the air and pushing on it, or something like that?

In case if anyone else wonders, here is the answer I've got from a different shop: GM's instructions for track alignment require to drill out the holes. (Since it's factory instructions, it's fine for the street class!) And after that the fronts can get to -2.7 or -2.8 degrees camber, and the rears to something like -1.7 degrees.

[clyde]

Originally Posted by sab123

In case if anyone else wonders, here is the answer I've got from a different shop: GM's instructions for track alignment require to drill out the holes. (Since it's factory instructions, it's fine for the street class!) And after that the fronts can get to -2.7 or -2.8 degrees camber, and the rears to something like -1.7 degrees.

I would strongly caution you to have GM documentation in your hard specifying that drilling and/or elongating holes are factory authorized for regular street use before proceeding down such a path.

I would also ask that you share that documentation before taking action so that you might have the opportunity to avail yourself of some higher quality input and advise than you may be getting from someone with a financial incentive to get you to authorize work that might be more expensive for you to undo later.

While it's possible that those running Camaros in National events that are quite familiar with rules and documentation could have missed something authorizing that work, it would be surprising.