Alignment spec question
Thread Starter
Race Director
Joined: Dec 2007
Posts: 19,574
Likes: 167
From: Frederick, MD
Alignment spec question
My steering wheel was slightly off center going down the road on my brand new 11 GS Vert so I took it in for an alignment.
Here are the specs (Caster/Camber/Toe). Out of limits ones are in red.
LF -1.2/8.1/.20
RF -1.1/8.1/.34
Total Toe .54, steer ahead -.07
LR -/-1/.04
RR -/-.7/-.11
Total Toe -.07
Thrust angle .07
LF -.6/7.4/-.01
RF -.4/7 .7/-.03
Total Toe -.04
Steer ahead .01
New rear settings were the same as above except both RR and LR toe are both .03, total toe .06, thrust angle 0.
Now the car takes a lot of concentration to go straight. It'll pull to the right mostly. Steering wheel has to be about 10 degrees to the left for the car to stay straight. Of course I have to maintain pressure on the wheel to keep it there. All specs currently are within GM specs but that isn't saying much. Any suggestions on what may be off. It is used on the street.
Here are the specs (Caster/Camber/Toe). Out of limits ones are in red.
LF -1.2/8.1/.20
RF -1.1/8.1/.34
Total Toe .54, steer ahead -.07
LR -/-1/.04
RR -/-.7/-.11
Total Toe -.07
Thrust angle .07
LF -.6/7.4/-.01
RF -.4/7 .7/-.03
Total Toe -.04
Steer ahead .01
New rear settings were the same as above except both RR and LR toe are both .03, total toe .06, thrust angle 0.
Now the car takes a lot of concentration to go straight. It'll pull to the right mostly. Steering wheel has to be about 10 degrees to the left for the car to stay straight. Of course I have to maintain pressure on the wheel to keep it there. All specs currently are within GM specs but that isn't saying much. Any suggestions on what may be off. It is used on the street.
Race Director
Joined: Mar 2011
Posts: 13,262
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From: SW Florida
2021 C6 of the Year Finalist - Modified
I can't understand why the car won't track straight anymore ... somethings wrong
But ... It looks like the car originally had a camber of about -1.2 degrees. That much camber will make for great cornering at the track, but will eat the inner edge of the tires real good.
If you want good tire wear, but still a good handling car, get them to set the camber at -0.4 degrees for all the wheels and the toe at 0.0" for all the wheels. (any toe-in or toe-out will also eat the tires)
Don't worry so much about the caster ... it should be set ok from the factory.
Oh ya .. Find a new alignment shop!
.
But ... It looks like the car originally had a camber of about -1.2 degrees. That much camber will make for great cornering at the track, but will eat the inner edge of the tires real good.
If you want good tire wear, but still a good handling car, get them to set the camber at -0.4 degrees for all the wheels and the toe at 0.0" for all the wheels. (any toe-in or toe-out will also eat the tires)
Don't worry so much about the caster ... it should be set ok from the factory.
Oh ya .. Find a new alignment shop!
.
Last edited by Turbo6TA; Oct 13, 2011 at 07:44 PM.
Team Owner
Joined: Sep 2000
Posts: 25,009
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
The minus numbers for front toe mean toe-out, and that tends to make the car "nervous". Great for over-caffinated autocrossers, not so good for the rest of us.
But the off-center steering wheel, and pulling; mean something is really messed up. Unless you have a tire problem, I'd go with the recommendation for a different alignment shop.
In the past, I've been happy with 0 toe front and rear, camber -.5 front and -.3 rear. Not very hard on the tires.
Let us know...
But the off-center steering wheel, and pulling; mean something is really messed up. Unless you have a tire problem, I'd go with the recommendation for a different alignment shop.
In the past, I've been happy with 0 toe front and rear, camber -.5 front and -.3 rear. Not very hard on the tires.
Let us know...
Last edited by Gearhead Jim; Oct 13, 2011 at 10:39 PM.
Advanced
Joined: Jun 2010
Posts: 62
Likes: 4
From: Rocklin California
My steering wheel was slightly off center going down the road on my brand new 11 GS Vert so I took it in for an alignment.
Here are the specs (Caster/Camber/Toe). Out of limits ones are in red.
LF -1.2/8.1/.20
RF -1.1/8.1/.34
Total Toe .54, steer ahead -.07
LR -/-1/.04
RR -/-.7/-.11
Total Toe -.07
Thrust angle .07
LF -.6/7.4/-.01
RF -.4/7 .7/-.03
Total Toe -.04
Steer ahead .01
New rear settings were the same as above except both RR and LR toe are both .03, total toe .06, thrust angle 0.
Now the car takes a lot of concentration to go straight. It'll pull to the right mostly. Steering wheel has to be about 10 degrees to the left for the car to stay straight. Of course I have to maintain pressure on the wheel to keep it there. All specs currently are within GM specs but that isn't saying much. Any suggestions on what may be off. It is used on the street.
Here are the specs (Caster/Camber/Toe). Out of limits ones are in red.
LF -1.2/8.1/.20
RF -1.1/8.1/.34
Total Toe .54, steer ahead -.07
LR -/-1/.04
RR -/-.7/-.11
Total Toe -.07
Thrust angle .07
LF -.6/7.4/-.01
RF -.4/7 .7/-.03
Total Toe -.04
Steer ahead .01
New rear settings were the same as above except both RR and LR toe are both .03, total toe .06, thrust angle 0.
Now the car takes a lot of concentration to go straight. It'll pull to the right mostly. Steering wheel has to be about 10 degrees to the left for the car to stay straight. Of course I have to maintain pressure on the wheel to keep it there. All specs currently are within GM specs but that isn't saying much. Any suggestions on what may be off. It is used on the street.
Now it tracks straight as an arrow, steering wheel is perfectly centered, and drives so much nicer. I couldn't believe the difference it made. Specs are now..
Caster LF 7.75
RF 8.14
Camber LF -0.47
RF -0.69
LR -0.50
RR -0.50
Toe RF .02
LF .01
RR .03
LR .03
Thread Starter
Race Director
Joined: Dec 2007
Posts: 19,574
Likes: 167
From: Frederick, MD
That is amazing the fronts last to 19.5k. Gen1 or Gen2 Goodyears?
Well it is still covered under warranty (only has 4k on it) so I'll take it back to the dealer. I figure the negative toe made it more "nervous". Factory setting was real stable but with high toe in .20/.34. Hopefully they'll be able to crank out some toe to zero or a little toe in (.01 or .02). The car does act like it is "hyper" right now.
If the dealer can't get it then we have JDP Motorsports here in SLC that is great with the Corvette's suspension.
Well it is still covered under warranty (only has 4k on it) so I'll take it back to the dealer. I figure the negative toe made it more "nervous". Factory setting was real stable but with high toe in .20/.34. Hopefully they'll be able to crank out some toe to zero or a little toe in (.01 or .02). The car does act like it is "hyper" right now.
If the dealer can't get it then we have JDP Motorsports here in SLC that is great with the Corvette's suspension.
Team Owner
Joined: Jun 2005
Posts: 46,295
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From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
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Thread Starter
Race Director
Joined: Dec 2007
Posts: 19,574
Likes: 167
From: Frederick, MD
Just got backed from the dealer. They said they "tweeked" it to the left. I went for a drive and the car tracked perfectly. It took a lot of crown in the road to make it want to go right. I asked for an spec sheet but they didn't save it. It feels like it is not "hyper" or nervous any more. They also adjusted the steering wheel a little. The car's steering wheel always seemed to be a little off even from the factory when it was tracking straight.
I know Talon90 (Paul) mentioned the factory is doing an alignment at the end of the line now instead of best guessing it. Time to enjoy the rest of the fall before the white stuff begins to fall.
I know Talon90 (Paul) mentioned the factory is doing an alignment at the end of the line now instead of best guessing it. Time to enjoy the rest of the fall before the white stuff begins to fall.
Instructor
Joined: Aug 2011
Posts: 155
Likes: 0
From: Va
Just had both my tires replaced and a major alignment effort put forth on my 350 mile 11 GS. Everything was significantly out of spec. A whole new set of tires, thank you GM and Goodyear.
I don't have the before numbers only the final that works great. By the way Turbo6TA the caster was more out of spec than the other front end stuff per the Tech.
Camber/Caster/toe
LF -.5*/7.8/.04 RF -.6/7.5/0.00
Total toe .04
Steer Ahead .03
Cam/Toe
LR -.04/.05 RR -.5/,02
TToe .07
Thrust .03
The other thing we are now playing with is tire pressure..Cold the fronts after a week were 28 heated to 32. The rears were LR 27/RR 28 heated to 30/31. Car was nervous.
Put in 31 around cold. Fronts heated to 34 and rears to 32/33. We are now going to try biasing the rears to +2#s over the fronts. Looking to get 31 front cold and 33 Rear cold which should get us to 34 heated all around. Just going to 31 took a bunch of nervous behavior out.
I don't have the before numbers only the final that works great. By the way Turbo6TA the caster was more out of spec than the other front end stuff per the Tech.
Camber/Caster/toe
LF -.5*/7.8/.04 RF -.6/7.5/0.00
Total toe .04
Steer Ahead .03
Cam/Toe
LR -.04/.05 RR -.5/,02
TToe .07
Thrust .03
The other thing we are now playing with is tire pressure..Cold the fronts after a week were 28 heated to 32. The rears were LR 27/RR 28 heated to 30/31. Car was nervous.
Put in 31 around cold. Fronts heated to 34 and rears to 32/33. We are now going to try biasing the rears to +2#s over the fronts. Looking to get 31 front cold and 33 Rear cold which should get us to 34 heated all around. Just going to 31 took a bunch of nervous behavior out.
Advanced
Joined: Jun 2010
Posts: 62
Likes: 4
From: Rocklin California
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
