Alignment Help Thread

[shibbs]

Originally Posted by JusticePete

Oversteer is not a concern with that setup.

Front Toe 0.00 will give you improved turn in ana more on center steering feel
Rear Camber -0.50 to save the inner shoulder on your 295/35 and reduce the push from the stagerred wheels / tires and OE bar ratios.

FYI - throttle induced oversteer is drifting :-)

Awesome. I was thinking BMR's specs of almost a degree in the rear were a bit high. Thanks!

[Firefighter]

Shibbs, would you be interested in a rear 1LE bar?

[wal-dog]

Taking my 2011 RS V6 in tomorrow for alignment. I'm lowered on BMR 1.2" drop springs. 275/40/20 all around. It's my daily driver with no tracking. Just want good tire wear. After reading the thread I've gathered that these settings are good.

Front Camber -1.00
Front Toe 0.00
Rear Camber -.5
Rear Toe IN .12
Total Rear Toe IN .24

I'm still confused on the rear toe. Should I tell the shop -.12 or +.12?

[Norm Peterson]

If you're looking at the alignment spec chart that I think you're looking at, the 0.12° toe spec is for cars having the rear suspension bushings replaced with firmer aftermarket bushings. The 0.24° spec is for cars still running the OE rubber bushings.

The convention for toe is that positive numbers mean that the tires are toed in, negative is where they're toed out. Rear wheels that are toed out can make for handling that feels a bit "nervous", so you probably don't want that.


Norm

[JusticePete]

Specs are Per SIDE except the TOTAL Rear Toe IN, for OE or aftermarket bushed 5th Gens.

Front Camber -1.00
Front Toe 0.00
Rear Camber -.5
Rear Toe IN .12
Total Rear Toe IN .24



Hope this helps.

[Norm Peterson]

Originally Posted by JusticePete

Specs are Per SIDE except the TOTAL Rear Toe IN, for OE or aftermarket bushed 5th Gens.

So Pete, does this mean that the note on the alignment pages from the "book" developed when you worked somewhere else that reads "Reduce Total Toe to .10 and .12 with full Ped**rs bushes" is no longer to be considered?

If so, what's the new reasoning?


Norm

[JusticePete]

Originally Posted by Norm Peterson

So Pete, does this mean that the note on the alignment pages from the "book" developed when you worked somewhere else that reads "Reduce Total Toe to .10 and .12 with full Ped**rs bushes" is no longer to be considered?

If so, what's the new reasoning?


Norm

GM has continuously improved the bushing in the 5th Gen over the production run and we have years of history with it. I wish I had written the book in Word and not on line. Updating it is a challenge with a post here and a post there. It is something I plan to do.

[Norm Peterson]

Still not sure I'm following it. Seems to me that firmer OE bushings would push the toe recommendations for OE bushed suspensions toward the smaller recommendation given previously for aftermarket, rather than relax the aftermarket-bushed configuration back toward OE . . . ???


Norm

[JusticePete]

Originally Posted by Norm Peterson

Still not sure I'm following it. Seems to me that firmer OE bushings would push the toe recommendations for OE bushed suspensions toward the smaller recommendation given previously for aftermarket, rather than relax the aftermarket-bushed configuration back toward OE . . . ???


Norm

They do. I am not sure I am following the reason you think it doesn't.

[wal-dog]

Originally Posted by JusticePete

Specs are Per SIDE except the TOTAL Rear Toe IN, for OE or aftermarket bushed 5th Gens.

Front Camber -1.00
Front Toe 0.00
Rear Camber -.5
Rear Toe IN .12
Total Rear Toe IN .24



Hope this helps.

Thanks Pete. What is an acceptable + or - on these settings or should I expect them to set it "dead balls accurate"?

[JusticePete]

Originally Posted by wal-dog

Thanks Pete. What is an acceptable + or - on these settings or should I expect them to set it "dead balls accurate"?

My preference is always dead nuts ball on accurate, but a few tenths won't ruin an alignment.

[Norm Peterson]

Originally Posted by JusticePete

They do. I am not sure I am following the reason you think it doesn't.

Compliance steer. The steer effect from bushing compliance is in the toe out direction when the more firmly bushed toe control link is placed ahead of the control arms.

Softer control arm bushings would call for a greater amount of static toe in to keep it from going out (or as far out if a little can be tolerated).

That very much fits the note on the old book's alignment specs page - use less static toe with firmer bushings. So if GM firmed up the OE bushings, why wouldn't the toe suggestion for OE go toward 0.12°?

I am assuming that neither the aftermarket control arm bushings nor the OE toe link bushings have been softened, so I am puzzled as to why the new recommendation for aftermarket bushings was increased.


Norm

[JusticePete]

The ZL1, 1LE and Z/28 all have sealed monoballs in the toelinks. Sub-frame bushings have been upgraded, some models more than others. Toe link bushes are now firmer.

All that is good, but we also have a years of experience on the chassis and find we can run these settings.

[Norm Peterson]

I don't doubt that 0.24° works for more firmly bushed cars; that's not my question.

What I am trying to get at is the reason for changing the recommendation for aftermarket-bushed cars when it's not likely that the aftermarket bushings have been made softer in the meantime. The net end result is a lot clearer than the 'why' behind it.


Norm