Street Touring Hatchback (STH) discussion/setup

[bfury5]

What tire?

Woops forgot to mention, I'm also running A052

 

[theDoktor]

Is this from Puhn’s handling book?

This chart is total toe measurement?

The chart is from the Watkins Smart String Owner's Handbook. The toe setting is toe amount in fractions of an inch or degrees PER WHEEL near as I can determine. Please feel free to correct me if I am wrong.

 

[theDoktor]

I'm considering higher front pressures to act as more spring, to keep the tire contact patch from being overloaded, in the same way that Jackrabbit suggested that we try higher front spring rates to make the front "happy".

What Jackrabit suggested is why I am considering installing a bigger front bar (H&R 26mm adjustable) and going back to the stock rear bar on my GS set-up, then tuning with tire pressures. Obviously can't legally do springs.

 

[bfury5]

What Jackrabit suggested is why I am considering installing a bigger front bar (H&R 26mm adjustable) and going back to the stock rear bar on my GS set-up, then tuning with tire pressures. Obviously can't legally do springs.

My guess is you'll have to run some pretty aggressive toe in the rear in addition to the bar to get the rotation. I get the "less front roll = more front grip" but I think in stock class, you're still fighting the rear more than the front.

Andy Hollis DM on FWD:
"Build your spring rates around the corner weights, and adjust bars to get the roll angle from there. if you do too much with springs, you'll reduce grip on bumpy surfaces. Since bar rates go up in rate exponentially, it's the only real way to large amounts of roll stiffness."

I would argue that a lot of us in the thread are already building springrates around the corner weights when we calculated suspension freq. front and back. The big differentiator between all of the setups is dampers, because low-speed damping curves will make a huge difference in how the spring is controlled and how the body rolls. A low low-speed compression rate might want more front bar vs a higher low-speed compression rate where the bar might not be needed.

 

[xXDavidCXx]

My guess is you'll have to run some pretty aggressive toe in the rear in addition to the bar to get the rotation. I get the "less front roll = more front grip" but I think in stock class, you're still fighting the rear more than the front.


I would argue that a lot of us in the thread are already building springrates around the corner weights when we calculated suspension freq. front and back. The big differentiator between all of the setups is dampers, because low-speed damping curves will make a huge difference in how the spring is controlled and how the body rolls. A low low-speed compression rate might want more front bar vs a higher low-speed compression rate where the bar might not be needed.

Keep in mind that dampers cannot control total roll, only the timing of the total roll.

 

[xXDavidCXx]

I think you're still within factory spec at .17 per side toe out front. Even at .21, the car drives fine and I'm not noticing any driveability issues on the street. I don't turn ESC off on the street, so if it did get a little rotatey on the street, the ESC completely kills the fun anyway.

Okay, based on this feedback I'll try 1/4 total toe, front and rear, and put the rear camber back up.

 

[xXDavidCXx]

What Jackrabit suggested is why I am considering installing a bigger front bar (H&R 26mm adjustable) and going back to the stock rear bar on my GS set-up, then tuning with tire pressures. Obviously can't legally do springs.

I had a similar front bar when I ran stock springs and shocks in STH. Did okay. You may pick up a front tire.

 

[bfury5]

Okay, based on this feedback I'll try 1/4 total toe, front and rear, and put the rear camber back up.

I forget if it's been mentioned (I think it has) but any chance at improving that t ont camber? That'll make a huge difference in front end grip

 

[xXDavidCXx]

I forget if it's been mentioned (I think it has) but any chance at improving that t ont camber? That'll make a huge difference in front end grip

Not without the new top mounts from GC, another $500. Not sure what else to do with the front.

Also scraping the passenger side, the side with more camber, inner body with the sway bar link. More camber will make this problem worse.

 

[Mini7]

I’m working on getting a set of PowerGrid endlinks if it gives me some more wiggle room compared to the SuperPro endlinks. The white,ins have the same profile of the SuperPros.

Just waiting on dimensions.

Will still likely take the die grinder to shave down the ears on the Ohlins.

 

[xXDavidCXx]

Okay, based on this feedback I'll try 1/4 total toe, front and rear, and put the rear camber back up.

View attachment 186848

Just measured the toe to make sure a positive number is toe out...

It's not.

Back to the alignment shop tomorrow.

Good thing I checked.

 

[bfury5]

Not without the new top mounts from GC, another $500. Not sure what else to do with the front.

Also scraping the passenger side, the side with more camber, inner body with the sway bar link. More camber will make this problem worse.

View attachment 186851

Do you think there's any chance of repositioning where the endlink attaches to the strut? Would moving the endlink down the strut get you more clearance to the fenderwell? Obviously that would require a shorter endlink and a hole in the strut, but just wondering. Or as @Mini7 mentioned, shaving down the ear on the strut.

 

[theDoktor]

Just measured the toe to make sure a positive number is toe out...

It's not.

Back to the alignment shop tomorrow.

Good thing I checked.

Good catch!

 

[xXDavidCXx]

Do you think there's any chance of repositioning where the endlink attaches to the strut? Would moving the endlink down the strut get you more clearance to the fenderwell? Obviously that would require a shorter endlink and a hole in the strut, but just wondering. Or as @Mini7 mentioned, shaving down the ear on the strut.

I’m not hacking up the strut.

Holding out for a slimmer end link

 

[xXDavidCXx]

Good catch!

Now have 1/8 inch total toe out front and rear.

Nothing to worry about on the front. I though it would be darty. It's fine.

The rear is more lively, should be a good time this weekend.