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Old 04-05-2008, 10:04 AM
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bj1k
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Default Another wheel alignment question

Just had all fours aligned on my 68 at a long time alignment shop in the area and these guys are really known for top notch work. I've had several of my corvettes aligned there with no problems. The right rear wheel appears to lean in and toe in more than the left rear when it is sitting on level concrete. He said it is supposed to be adjusted that way to adjust for the crown in the center of the road. Is this or do you notice the same thing on yours. Don't want to wear out the new tires and then find out that it is not right.
Old 04-05-2008, 10:45 AM
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rfn026
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When most alignment shops adjust for the crown in the road they usually do it with the front toe setting.

It's a little unusual for a shop to do that correction with rear camber and rear toe.

If it were my car I would want the toe and camber settings equal on both the right and left side. Also, have them put as much caster in the front as possible.

This sounds like a do-over to me.

Richard Newton

Wheel and Tire Performance Handbook

How to Restore and Modify Your Corvette, 1968-1982
Old 04-05-2008, 11:36 AM
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sly vette
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Originally Posted by rfn026
When most alignment shops adjust for the crown in the road they usually do it with the front toe setting.

It's a little unusual for a shop to do that correction with rear camber and rear toe.

If it were my car I would want the toe and camber settings equal on both the right and left side. Also, have them put as much caster in the front as possible.

This sounds like a do-over to me.

Richard Newton

Wheel and Tire Performance Handbook

How to Restore and Modify Your Corvette, 1968-1982

I also suggest a zero toe in the front....That has worked the best for me. Less darting IMHO.
Old 04-05-2008, 11:43 AM
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SanDiegoPaul
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Originally Posted by rfn026
When most alignment shops adjust for the crown in the road they usually do it with the front toe setting.

It's a little unusual for a shop to do that correction with rear camber and rear toe.

If it were my car I would want the toe and camber settings equal on both the right and left side. Also, have them put as much caster in the front as possible.

This sounds like a do-over to me.

Richard Newton

Wheel and Tire Performance Handbook

How to Restore and Modify Your Corvette, 1968-1982
Yep that needs to be redone. Doesnt' sound like that side on the rear was set up properly. You ABSOLUTELY DO NOT!!! correct for road crown with one rear wheel setting. He's lying to you.

Therre may also be a mechanical problem on that rear side, so be sure all is tight under there before taking it back to him.
Old 04-05-2008, 08:19 PM
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bj1k
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Originally Posted by SanDiegoPaul
Yep that needs to be redone. Doesnt' sound like that side on the rear was set up properly. You ABSOLUTELY DO NOT!!! correct for road crown with one rear wheel setting. He's lying to you.

Therre may also be a mechanical problem on that rear side, so be sure all is tight under there before taking it back to him.
There's no mechanical problems. Everything is new. I'm going to have another alignment shop look at it. They were always a good alignment shop but the guy that did mine was a new face. Probably didn't know what he was doing but the owner was covering for him.
Old 04-06-2008, 12:39 AM
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TheSkunkWorks
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IMHO, I don't believe in compensating for crown on a sports car, done correctly or not. Leave that for the wife's minivan.

Also, if you have manual steering I wouldn't suggest cranking in more than ~2* positive caster on the street, as in addition to further reducing any tendency for dartiness it will also serve to increase steering effort at parking lot speeds (more scrub). With PS, you can get away with a good bit more positive caster.

BTW, you'll need some toe-in up front, especially if you run rubber control arm bushings. With poly, you don't need as much, but I'd save zero to neg toe for auto-X setups. Having some toe in actually has a stabilizing effect against darting about when encountering upsets.


Last edited by TheSkunkWorks; 04-06-2008 at 12:49 AM.
Old 04-06-2008, 11:12 AM
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Originally Posted by TheSkunkWorks
IMHO, I don't believe in compensating for crown on a sports car, done correctly or not. Leave that for the wife's minivan.

Also, if you have manual steering I wouldn't suggest cranking in more than ~2* positive caster on the street, as in addition to further reducing any tendency for dartiness it will also serve to increase steering effort at parking lot speeds (more scrub). With PS, you can get away with a good bit more positive caster.

BTW, you'll need some toe-in up front, especially if you run rubber control arm bushings. With poly, you don't need as much, but I'd save zero to neg toe for auto-X setups. Having some toe in actually has a stabilizing effect against darting about when encountering upsets.

Actually as I stated earlier, I found that with my '69 roadster no power steering, that I found my best toe setting to be "0". Again that is what is best for me. No darting at all. This was after I had a "professional" alignment.
I don't really know where the toe was set at from the shop but when I felt some lack of control after the pro alignment I found the centerline of the car and adjusted my rotors to be "perfectly parallel" with that line.
Of course all of this was done with the weight of the car on the susp.
Good Luck,
Mark
Old 04-07-2008, 12:16 PM
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If you want to play around with your alignments you might try a slight amount of toe-out on the front. This can be great for autocross events. The toe-out means a quicker turn-in.

Some folks like it - some don't. It's worth the effort to try it on a test and tune day. You can mark the original settings with a white paint stripe.

Richard Newton
Old 04-07-2008, 02:54 PM
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Originally Posted by sly vette
Actually as I stated earlier, I found that with my '69 roadster no power steering, that I found my best toe setting to be "0". Again that is what is best for me. No darting at all. This was after I had a "professional" alignment.
I don't really know where the toe was set at from the shop but when I felt some lack of control after the pro alignment I found the centerline of the car and adjusted my rotors to be "perfectly parallel" with that line.
Of course all of this was done with the weight of the car on the susp.
Good Luck,
Mark
Toe-in is usually recommended to prevent dartiness. There's something about the Corvette suspension, though - I zeroed my front toe out as a temporary setting to get it drivable, and it feels great.
Old 04-07-2008, 04:29 PM
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Before I begin, let me stipulate that with poly control arm bushings the following issue is reduced to being almost irrelevant. However, since not everyone has seen the light about poly CA bushings (not to be confused with TA's), one big reason that I would recommend some toe-in is due to rubber control arm bushing compliance (), which due to the rolling resistance of the front tires allows the front alignment to move towards toe out from whatever the static setting may be. The higher the speeds, the bigger the change, and under heavy braking loads (read, "maximum rolling resistance") that change can be even more significant.

Any debate about dartiness aside, zero static toe with rubber bushings means tire scrub. Don't think that's susbtantial? Back in the day we once clipped nearly 0.5 sec off of the 1/4 mi ET of a pro bracket car I was campaigning by re-aligning the front at "under acceleration" ride heights. Best ET's were seen with zero camber, but some static toe-in at that height to compensate for the rubber bushings. Just imagine the impact on fuel economy scrub no doubt has...

Lastly, while I agree wholeheartedly that toe-out can improve initial turn-in, increased Ackerman (which typical bumpsteer blocks provide), can serve to reduce the amount required which, of course, translates back into reduced straight-line scrub.

Old 04-13-2008, 12:39 PM
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All I can attest to is that with zero toe and poly control arm bushings, the dartieness(sp) for my car has been eliminated.
I notice it especially on the highway during lane changes....smooth as silk!!!
But also there is no wear on any of my steering or suspension parts due to the fact that the car was rebuilt with all new parts AND fasteners.

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