Alignment Guru's
Thread Starter
Instructor
Joined: May 2013
Posts: 158
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From: Ct
If you are looking for a shop who knows C3s and other generations Corvette center of Newington is the place. I am very picky about anyone working on my car so I avoid it at all costs. But the alignment is something I am just not set op to do. I did a complete suspension rebuild and then had the corvette center do the alignment. Ray and his crew are top notch. I couldn't have been more happy with it! It handles like it is supposed to now. Great on the highway. Ray and I discussed just how I wanted it set up and he was all over the specs I suggested. I highly recommend them.
Mike
Mike
I purchased a few thing from Ray back in 90/91. He rebuilt a steering box for em. I called him today; he said he's backed up until next week. He's located 30 miles from me; I'm in Morris, 3 miles south of the Litchfield green. The alignment shop I chose was recommended by a long time hot rod shop and it's 11 miles from me.
Last edited by PeteL46; Sep 16, 2014 at 10:17 PM. Reason: spelling
Thread Starter
Instructor
Joined: May 2013
Posts: 158
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From: Ct
The alignment shop called me this morning asking for the specs I brought in so they could compare. They called me this after and said they aligned it to incorrect specs. . . bring it in.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
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From: Graceland in a Not Correctly Restored Stingray
Thread Starter
Instructor
Joined: May 2013
Posts: 158
Likes: 1
From: Ct
CASTER: As already mentioned, you do NOT want caster split on a sportscar. Get that equalized. While I'm not big on running much caster at all with manual steering, I would generally recommend no less than ~2 degrees with PS.
FRONT TOE: As already mentioned, you do NOT want front toe-out, except possibly for when you might find yourself AX'ing or RR'ing on a tight course with predominately slow corners.
REAR TOE: Out back, you might actually have a touch more than necessary if you're at standard ride height. That said, if your running very much lower you might want to leave this item alone.
CAMBER: Depends very much on your purposes and/or how you drive most of the time. I typically run a good bit more up front than on the rear, but I likely reside a bit nearer the hardcore end of the scale.
In any event, next time you head to the alignment shop, why not download alignment recommendations such as those offered by Guldstrand or VBP, pick the set which best matches with your priorities, and tell the shop to adhere as strictly as is practical to those preferred specs. My $.02
edit - To clarify, if the fronts are aiming inward towards the transmission, you have front toe-out.
FRONT TOE: As already mentioned, you do NOT want front toe-out, except possibly for when you might find yourself AX'ing or RR'ing on a tight course with predominately slow corners.
REAR TOE: Out back, you might actually have a touch more than necessary if you're at standard ride height. That said, if your running very much lower you might want to leave this item alone.
CAMBER: Depends very much on your purposes and/or how you drive most of the time. I typically run a good bit more up front than on the rear, but I likely reside a bit nearer the hardcore end of the scale.
In any event, next time you head to the alignment shop, why not download alignment recommendations such as those offered by Guldstrand or VBP, pick the set which best matches with your priorities, and tell the shop to adhere as strictly as is practical to those preferred specs. My $.02
edit - To clarify, if the fronts are aiming inward towards the transmission, you have front toe-out.
I was hoping you could advise. I'vetook your advice and looked at Guldstrand and VBP's "Touring" specs and they appear quite different. Toe: VB=1/32, Guld=1/8 to 3/16. Camb: VB=0, Guld=1/4 to 1/2. etc. I'm lost. . somewhat leaning to Guld because they'recloser to factory specs but truly a guess. I can take them apart, clean, paint and make them look pretty but alignments...fugetaboutit! May I ask what you'd pick?
245's in the front with 255's in the rear. It appears the VB is closer to BB's specs for wider tires.
Last edited by PeteL46; Sep 16, 2014 at 10:23 PM. Reason: Edit: adding information
Melting Slicks
Joined: Jun 2011
Posts: 3,116
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TheSkunkWorks, BB or anyone else,
I was hoping you could advise. I'vetook your advice and looked at Guldstrand and VBP's "Touring" specs and they appear quite different. Toe: VB=1/32, Guld=1/8 to 3/16. Camb: VB=0, Guld=1/4 to 1/2. etc. I'm lost. . somewhat leaning to Guld because they'recloser to factory specs but truly a guess. I can take them apart, clean, paint and make them look pretty but alignments...fugetaboutit! May I ask what you'd pick?
245's in the front with 255's in the rear. It appears the VB is closer to BB's specs for wider tires.
I was hoping you could advise. I'vetook your advice and looked at Guldstrand and VBP's "Touring" specs and they appear quite different. Toe: VB=1/32, Guld=1/8 to 3/16. Camb: VB=0, Guld=1/4 to 1/2. etc. I'm lost. . somewhat leaning to Guld because they'recloser to factory specs but truly a guess. I can take them apart, clean, paint and make them look pretty but alignments...fugetaboutit! May I ask what you'd pick?
245's in the front with 255's in the rear. It appears the VB is closer to BB's specs for wider tires.
1 the balance from left and right side
in the following order.
1. caster left vs right on the front. best left=right or +- .1 degree
2. camber left vs right left=right or +- .1 degree
3. thrust angle. This is the driving angle of the rear wheels vs the front wheels. ( this must be very close to zero )
the amount of toe in helps with uneven road wonder.
The more front toe-in less wonder but less responsive in handling and shorter tire life.
Front toe out provides lots of road wander, very fast handling and shorter tire life.
Balance is very little toe-in
Rear Toe affects over-steer and under-steer handling. Rear toe-out help induce initial over steer and Rear toe-in helps induce initial under steer.
Balance is more toe-in to help prevent initial over-steer ( back-end snapping around)
A very good street alignment is
front
caster > 2.4 degrees left = right (must get this right)
camber 0 degrees or -.1 degree ( top of tire tilted in ) left = right +- 0.1
"Total Toe-in" 1/32" - 1/16" tires pointing inward toward the center.
Rear
caster (NA) no caster
camber -.1 to -.5 (top of tire tilted in ) left = right +- 0.1
"Total Toe-in" 1/16 - 1/8 tires pointing inward same as front tires
Thrust angle should be 0 to .01 degrees. (important)
I do my own alignments because I use my car for street and track road course driving. The alignment shops are not as fussy as I am getting the balance left vs right.
https://www.corvetteforum.com/forums...n-opinion.html
See post #13 this is how I align my car.
Last edited by cagotzmann; Sep 17, 2014 at 12:22 AM.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
TheSkunkWorks or anyone else,
I was hoping you could advise. I'vetook your advice and looked at Guldstrand and VBP's "Touring" specs and they appear quite different. Toe: VB=1/32, Guld=1/8 to 3/16. Camb: VB=0, Guld=1/4 to 1/2. etc. I'm lost. . somewhat leaning to Guld because they'recloser to factory specs but truly a guess. I can take them apart, clean, paint and make them look pretty but alignments...fugetaboutit! May I ask what you'd pick?
245's in the front with 255's in the rear
I was hoping you could advise. I'vetook your advice and looked at Guldstrand and VBP's "Touring" specs and they appear quite different. Toe: VB=1/32, Guld=1/8 to 3/16. Camb: VB=0, Guld=1/4 to 1/2. etc. I'm lost. . somewhat leaning to Guld because they'recloser to factory specs but truly a guess. I can take them apart, clean, paint and make them look pretty but alignments...fugetaboutit! May I ask what you'd pick?
245's in the front with 255's in the rear
At the rear, given that the C2/C3 IRS geometry produces inherently adverse rear toe-steer during suspension travel (more important when loaded in bump or squat), rear toe settings are exceedingly dependent on rear ride height, as I had alluded to in an earlier post. Tho I've experimented on track with static toe-out on SLA rear suspensions, I wouldn't recommend that any C2/C3 based IRS be set up with insufficient rear toe-in on purpose. General rule here is, the lower the rear ride height (relative to the half-shafts), the more static toe-in necessary to counter this problem. As with all alignment and suspension geometry parameters, there is a point of diminishing returns beyond which further compensation just adds scrub. I refrain from quoting the maths on this, as they'd be compromised by TA bushing compliance anyway.
Front camber isn't as straight forward (happy coincidence) as is toe. If you don't often push so much when the steering wheel isn't pointing directly ahead, 0* static camber is fine, and should give you excellent tread wear. But, if you occasionally drive out of your way to go thru a few favorite curvy sections, I'd suggest at least 1/4*. If you tend to press a bit and more often than not when you get to those curves, I'd probably start at 1/2*. Of course, if you find yourself up around 7/10ths or more of your or your car's limits and liking it, it's time to reevaluate what range of specs might better suit. (And, by all means, do NOT mistake how your car may feel at 7 or even 8/10ths with how it might react at or above 10/10ths!)
Rear camber too depends on the above, but is also sensitive to the relationship between power and available traction. The less able you are to add power before fully exiting corners, or the higher priority is placed on straight-line acceleration, the less rear camber will be desired. If you can just mat the throttle anytime, then you can set rear camber exclusively for cornering. There is also the matter of camber gain during suspension travel, as well as a good many other nuances, but IMHO more advanced topics such as those are best left to other discussions down the road.
In any event, I do hope my approach to alignment setup hasn't confused matters, as I'm not intent on being vague with my comments. I was learnt more on track and from hanging around racing prep-shops since I was a pup, rather than out of a shop manual. That experience taught me that there are no absolutes in chassis tuning that can be equally applied to every circumstance, other than the vehicle dynamics maths being among the most tangled cans of worms. Reality is, no one ever hits squarely on the perfect alignment and chassis setup, not even in F1. (Well, perhaps Jim Clark could.) So, don't sweat it too much if you don't happen to do so either. You're in good company.
That said, yes, we can get the alignment dang close for a lot of us (assuming the chassis and suspension don't pose us with too many problems in and of themselves). What Dick Guldstrand, VBP and others attempt to do when establishing recommendations is to arrive at a set of sound baselines from which enthusiasts within a wide range of various purposes can work. Tho opinions among these sources vary, many are satisfied by their recommendations without making further adjustment, while others may chase alignment and geometry demon tweaks for years on end. And, other than the frequently bloodshot eyes, there's nothing wrong with finding one's self in either camp, if not somewhere in-between.
Hope that leaves you with a bit more of a fishing pole than simply a fish.
Last edited by TheSkunkWorks; Sep 17, 2014 at 03:34 AM.
Thread Starter
Instructor
Joined: May 2013
Posts: 158
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From: Ct
For "touring", with standard rubber CA bushings I'd suggest starting at 1/8" front toe-in, while with poly I'd move closer to the 1/32". The more compliant are the bushings, the more they'll tend to yield to scrub and rolling resistance, and allow the front end to push back towards or into toe-out. While front toe-out can help a car point initially into low-speed turns, IMOE even "trick" rubber CA bushings with skinny front drag tires require a touch of toe-in.
At the rear, given that the C2/C3 IRS geometry produces inherently adverse rear toe-steer during suspension travel (more important when loaded in bump or squat), rear toe settings are exceedingly dependent on rear ride height, as I had alluded to in an earlier post. Tho I've experimented on track with static toe-out on SLA rear suspensions, I wouldn't recommend that any C2/C3 based IRS be set up with insufficient rear toe-in on purpose. General rule here is, the lower the rear ride height (relative to the half-shafts), the more static toe-in necessary to counter this problem. As with all alignment and suspension geometry parameters, there is a point of diminishing returns beyond which further compensation just adds scrub. I refrain from quoting the maths on this, as they'd be compromised by TA bushing compliance anyway.
Front camber isn't as straight forward (happy coincidence) as is toe. If you don't often push so much when the steering wheel isn't pointing directly ahead, 0* static camber is fine, and should give you excellent tread wear. But, if you occasionally drive out of your way to go thru a few favorite curvy sections, I'd suggest at least 1/4*. If you tend to press a bit and more often than not when you get to those curves, I'd probably start at 1/2*. Of course, if you find yourself up around 7/10ths or more of your or your car's limits and liking it, it's time to reevaluate what range of specs might better suit. (And, by all means, do NOT mistake how your car may feel at 7 or even 8/10ths with how it might react at or above 10/10ths!)
Rear camber too depends on the above, but is also sensitive to the relationship between power and available traction. The less able you are to add power before fully exiting corners, or the higher priority is placed on straight-line acceleration, the less rear camber will be desired. If you can just mat the throttle anytime, then you can set rear camber exclusively for cornering. There is also the matter of camber gain during suspension travel, as well as a good many other nuances, but IMHO more advanced topics such as those are best left to other discussions down the road.
In any event, I do hope my approach to alignment setup hasn't confused matters, as I'm not intent on being vague with my comments. I was learnt more on track and from hanging around racing prep-shops since I was a pup, rather than out of a shop manual. That experience taught me that there are no absolutes in chassis tuning that can be equally applied to every circumstance, other than the vehicle dynamics maths being among the most tangled cans of worms. Reality is, no one ever hits squarely on the perfect alignment and chassis setup, not even in F1. (Well, perhaps Jim Clark could.) So, don't sweat it too much if you don't happen to do so either. You're in good company.
That said, yes, we can get the alignment dang close for a lot of us (assuming the chassis and suspension don't pose us with too many problems in and of themselves). What Dick Guldstrand, VBP and others attempt to do when establishing recommendations is to arrive at a set of sound baselines from which enthusiasts within a wide range of various purposes can work. Tho opinions among these sources vary, many are satisfied by their recommendations without making further adjustment, while others may chase alignment and geometry demon tweaks for years on end. And, other than the frequently bloodshot eyes, there's nothing wrong with finding one's self in either camp, if not somewhere in-between.
Hope that leaves you with a bit more of a fishing pole than simply a fish.
At the rear, given that the C2/C3 IRS geometry produces inherently adverse rear toe-steer during suspension travel (more important when loaded in bump or squat), rear toe settings are exceedingly dependent on rear ride height, as I had alluded to in an earlier post. Tho I've experimented on track with static toe-out on SLA rear suspensions, I wouldn't recommend that any C2/C3 based IRS be set up with insufficient rear toe-in on purpose. General rule here is, the lower the rear ride height (relative to the half-shafts), the more static toe-in necessary to counter this problem. As with all alignment and suspension geometry parameters, there is a point of diminishing returns beyond which further compensation just adds scrub. I refrain from quoting the maths on this, as they'd be compromised by TA bushing compliance anyway.
Front camber isn't as straight forward (happy coincidence) as is toe. If you don't often push so much when the steering wheel isn't pointing directly ahead, 0* static camber is fine, and should give you excellent tread wear. But, if you occasionally drive out of your way to go thru a few favorite curvy sections, I'd suggest at least 1/4*. If you tend to press a bit and more often than not when you get to those curves, I'd probably start at 1/2*. Of course, if you find yourself up around 7/10ths or more of your or your car's limits and liking it, it's time to reevaluate what range of specs might better suit. (And, by all means, do NOT mistake how your car may feel at 7 or even 8/10ths with how it might react at or above 10/10ths!)
Rear camber too depends on the above, but is also sensitive to the relationship between power and available traction. The less able you are to add power before fully exiting corners, or the higher priority is placed on straight-line acceleration, the less rear camber will be desired. If you can just mat the throttle anytime, then you can set rear camber exclusively for cornering. There is also the matter of camber gain during suspension travel, as well as a good many other nuances, but IMHO more advanced topics such as those are best left to other discussions down the road.
In any event, I do hope my approach to alignment setup hasn't confused matters, as I'm not intent on being vague with my comments. I was learnt more on track and from hanging around racing prep-shops since I was a pup, rather than out of a shop manual. That experience taught me that there are no absolutes in chassis tuning that can be equally applied to every circumstance, other than the vehicle dynamics maths being among the most tangled cans of worms. Reality is, no one ever hits squarely on the perfect alignment and chassis setup, not even in F1. (Well, perhaps Jim Clark could.) So, don't sweat it too much if you don't happen to do so either. You're in good company.
That said, yes, we can get the alignment dang close for a lot of us (assuming the chassis and suspension don't pose us with too many problems in and of themselves). What Dick Guldstrand, VBP and others attempt to do when establishing recommendations is to arrive at a set of sound baselines from which enthusiasts within a wide range of various purposes can work. Tho opinions among these sources vary, many are satisfied by their recommendations without making further adjustment, while others may chase alignment and geometry demon tweaks for years on end. And, other than the frequently bloodshot eyes, there's nothing wrong with finding one's self in either camp, if not somewhere in-between.
Hope that leaves you with a bit more of a fishing pole than simply a fish.
I gave them toe in of 1/8 max, they gave me .34 deg left and .35 deg right.
Below is the alignment my car sit at today. I haven't driven it yet but my son say it pulls left as it hits the crown though he's used to driving 98 Z28/LS1. I would think that the front and rear tow would be somewhat close since I gave them 1/8 max for both.
Toe in L=.34 deg R= .35 deg
Camber L=-.5 deg R=-.6 deg
Caster L=2.2 deg R= 2.5 deg
Rear
Camber L=-.5 deg R=-.5 deg
Toe in L =.21 deg R = .14 deg
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Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
Well I went with Guldstrand Touring though I stayed on the high side of the specs. The alignment shop gave it another shot today. Son # 2 brought it down for me. Can you tell me what toe in 1/8 equates to in degrees?
I gave them toe in of 1/8 max, they gave me .34 deg left and .35 deg right.
Below is the alignment my car sit at today. I haven't driven it yet but my son say it pulls left as it hits the crown though he's used to driving 98 Z28/LS1. I would think that the front and rear tow would be somewhat close since I gave them 1/8 max for both.
Toe in L=.34 deg R= .35 deg
Camber L=-.5 deg R=-.6 deg
Caster L=2.2 deg R= 2.5 deg
Rear
Camber L=-.5 deg R=-.5 deg
Toe in L =.21 deg R = .14 deg
I gave them toe in of 1/8 max, they gave me .34 deg left and .35 deg right.
Below is the alignment my car sit at today. I haven't driven it yet but my son say it pulls left as it hits the crown though he's used to driving 98 Z28/LS1. I would think that the front and rear tow would be somewhat close since I gave them 1/8 max for both.
Toe in L=.34 deg R= .35 deg
Camber L=-.5 deg R=-.6 deg
Caster L=2.2 deg R= 2.5 deg
Rear
Camber L=-.5 deg R=-.5 deg
Toe in L =.21 deg R = .14 deg
You have about 9/32 total toe. more than 1/4"
The left rear has to much toe the right rear is good.
Did they measure / show you the thrust angle ?
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Well I went with Guldstrand Touring though I stayed on the high side of the specs. The alignment shop gave it another shot today. Son # 2 brought it down for me. Can you tell me what toe in 1/8 equates to in degrees?
I gave them toe in of 1/8 max, they gave me .34 deg left and .35 deg right.
Below is the alignment my car sit at today. I haven't driven it yet but my son say it pulls left as it hits the crown though he's used to driving 98 Z28/LS1. I would think that the front and rear tow would be somewhat close since I gave them 1/8 max for both.
Toe in L=.34 deg R= .35 deg
Camber L=-.5 deg R=-.6 deg
Caster L=2.2 deg R= 2.5 deg
Rear
Camber L=-.5 deg R=-.5 deg
Toe in L =.21 deg R = .14 deg
I gave them toe in of 1/8 max, they gave me .34 deg left and .35 deg right.
Below is the alignment my car sit at today. I haven't driven it yet but my son say it pulls left as it hits the crown though he's used to driving 98 Z28/LS1. I would think that the front and rear tow would be somewhat close since I gave them 1/8 max for both.
Toe in L=.34 deg R= .35 deg
Camber L=-.5 deg R=-.6 deg
Caster L=2.2 deg R= 2.5 deg
Rear
Camber L=-.5 deg R=-.5 deg
Toe in L =.21 deg R = .14 deg
Example: 1/16" x 2 = 1/8" = 0.26* total toe
Front toe: .34* + .35* = .69* = 0.326" (between 5/16" and 3/8") total front toe
Rear toe: .21* + .14* = .35* = 0.165" (between 1/8" and 3/16") total rear toe, with .035* thrust angle right
Comments:
1) You have .43* or ~0.2" more front toe than the 1/8" max you specified.
2) Front cross caster of .3* is significant for any sportscar, where 0* difference is preferable IMCO.
3) Front cross camber of .1*, potentially resulting in unequal camber thrust generation in left vs. right turns (read, "the front tires may not build cornering forces equally"), but you aren't likely to notice unless you're chasing down 1/10ths of a second at the track.
4) Rear total toe may be OK, but individually right rear toe could be insufficient, while the resulting thrust angle of .035* misses our 0* target. However, without knowing your static rear suspension ride height - specifically the "D" height, or difference between the heights of your inner and outer camber strut bolt CLs - I'd be speculating a bit to render better advice in regards rear toe-steer and thrust angle correction.
Am I picking at nits here? Maybe. But, IMHO I'd think that a shop truly familiar with the C2/C3 chassis would too.
Last edited by TheSkunkWorks; Sep 19, 2014 at 03:53 AM.
Thread Starter
Instructor
Joined: May 2013
Posts: 158
Likes: 1
From: Ct
Now that I have a base to start with can't I tweak the toe myself? MY guess would be 1/4 trun will put me on the + side of a 1/16???
So 1/8 = 9/64th of 1 deg?
Steer Ahead And Thrust Angle
Front - total toe .69 deg, steer ahead 0.00
Rear - total toe .35 deg, thrust angle .03 deg
Last edited by PeteL46; Sep 19, 2014 at 03:24 PM. Reason: added thrust angle
Thread Starter
Instructor
Joined: May 2013
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From: Ct
Toe conversions, assuming 255/60R15 tires (27.05" dia.)...
Example: 1/16" x 2 = 1/8" = 0.26* total toe
Front toe: .34* + .35* = .69* = 0.326" (between 5/16" and 3/8") total front toe
Rear toe: .21* + .14* = .35* = 0.165" (between 1/8" and 3/16") total rear toe, with .035* thrust angle right
Comments:
1) You have .43* or ~0.2" more front toe than the 1/8" max you specified.
2) Front cross caster of .3* is significant for any sportscar, where 0* difference is preferable IMCO.
3) Front cross camber of .1*, potentially resulting in unequal camber thrust generation in left vs. right turns (read, "the front tires may not build cornering forces equally"), but you aren't likely to notice unless you're chasing down 1/10ths of a second at the track.
4) Rear total toe may be OK, but individually right rear toe could be insufficient, while the resulting thrust angle of .035* misses our 0* target. However, without knowing your static rear suspension ride height - specifically the "D" height, or difference between the heights of your inner and outer camber strut bolt CLs - I'd be speculating a bit to render better advice in regards rear toe-steer and thrust angle correction.
Am I picking at nits here? Maybe. But, IMHO I'd think that a shop truly familiar with the C2/C3 chassis would too.
Example: 1/16" x 2 = 1/8" = 0.26* total toe
Front toe: .34* + .35* = .69* = 0.326" (between 5/16" and 3/8") total front toe
Rear toe: .21* + .14* = .35* = 0.165" (between 1/8" and 3/16") total rear toe, with .035* thrust angle right
Comments:
1) You have .43* or ~0.2" more front toe than the 1/8" max you specified.
2) Front cross caster of .3* is significant for any sportscar, where 0* difference is preferable IMCO.
3) Front cross camber of .1*, potentially resulting in unequal camber thrust generation in left vs. right turns (read, "the front tires may not build cornering forces equally"), but you aren't likely to notice unless you're chasing down 1/10ths of a second at the track.
4) Rear total toe may be OK, but individually right rear toe could be insufficient, while the resulting thrust angle of .035* misses our 0* target. However, without knowing your static rear suspension ride height - specifically the "D" height, or difference between the heights of your inner and outer camber strut bolt CLs - I'd be speculating a bit to render better advice in regards rear toe-steer and thrust angle correction.
Am I picking at nits here? Maybe. But, IMHO I'd think that a shop truly familiar with the C2/C3 chassis would too.
I checked the rear camber strut dimension last month though I only used a tape measure. As I recall it was within a 1/32-1/16 of the "D" dim. in th AIM. Maybe I should have measured with a vernier.
Last edited by PeteL46; Sep 19, 2014 at 04:12 PM. Reason: add info ADDED the phrase "D" dim.
Pro
Joined: Apr 2013
Posts: 535
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From: London Ontario
I just returned from having mine aligned by a local tire shop. I lucked out and they had an older mechanic that was quite familiar with C3 steering geometry.
I gave him the VB and P 'advanced street' setting as mentioned on the thread (thanks!) and had very little concern with those numbers. I just completed a full front suspension rebuild (steering hydraulics as well) so knew the toe would be off at a minimum.
As found: Caster L 2.61, R 3.25 Camber L +.40, R +.48 Toe L +.18 R +.21 total +.39
After removing 4 shims (expected as the alignment has never been done since new) he was able to get it to: Caster L 2.54 R 3.13 Camber L -.27 R -.15 Toe -.12 equal with a total of -.24
Rear wasn't touched but is Toe L .04 R .10, Camber L .40 R .56
It now handles like a new car with no bump steer or wander at all. I took it on the highway and hit 100mph (shhhh don't tell!) and it runs hands off with a 2% crossfall on the road. Thats awesome for our 40+ year old cars! This is with 255/60 BFGs all around.
The total cost was a whopping $90 plus tax.
I gave him the VB and P 'advanced street' setting as mentioned on the thread (thanks!) and had very little concern with those numbers. I just completed a full front suspension rebuild (steering hydraulics as well) so knew the toe would be off at a minimum.
As found: Caster L 2.61, R 3.25 Camber L +.40, R +.48 Toe L +.18 R +.21 total +.39
After removing 4 shims (expected as the alignment has never been done since new) he was able to get it to: Caster L 2.54 R 3.13 Camber L -.27 R -.15 Toe -.12 equal with a total of -.24
Rear wasn't touched but is Toe L .04 R .10, Camber L .40 R .56
It now handles like a new car with no bump steer or wander at all. I took it on the highway and hit 100mph (shhhh don't tell!) and it runs hands off with a 2% crossfall on the road. Thats awesome for our 40+ year old cars! This is with 255/60 BFGs all around.
The total cost was a whopping $90 plus tax.
Thread Starter
Instructor
Joined: May 2013
Posts: 158
Likes: 1
From: Ct
I just returned from having mine aligned by a local tire shop. I lucked out and they had an older mechanic that was quite familiar with C3 steering geometry.
I gave him the VB and P 'advanced street' setting as mentioned on the thread (thanks!) and had very little concern with those numbers. I just completed a full front suspension rebuild (steering hydraulics as well) so knew the toe would be off at a minimum.
As found: Caster L 2.61, R 3.25 Camber L +.40, R +.48 Toe L +.18 R +.21 total +.39
After removing 4 shims (expected as the alignment has never been done since new) he was able to get it to: Caster L 2.54 R 3.13 Camber L -.27 R -.15 Toe -.12 equal with a total of -.24
Rear wasn't touched but is Toe L .04 R .10, Camber L .40 R .56
It now handles like a new car with no bump steer or wander at all. I took it on the highway and hit 100mph (shhhh don't tell!) and it runs hands off with a 2% crossfall on the road. Thats awesome for our 40+ year old cars! This is with 255/60 BFGs all around.
The total cost was a whopping $90 plus tax.
I gave him the VB and P 'advanced street' setting as mentioned on the thread (thanks!) and had very little concern with those numbers. I just completed a full front suspension rebuild (steering hydraulics as well) so knew the toe would be off at a minimum.
As found: Caster L 2.61, R 3.25 Camber L +.40, R +.48 Toe L +.18 R +.21 total +.39
After removing 4 shims (expected as the alignment has never been done since new) he was able to get it to: Caster L 2.54 R 3.13 Camber L -.27 R -.15 Toe -.12 equal with a total of -.24
Rear wasn't touched but is Toe L .04 R .10, Camber L .40 R .56
It now handles like a new car with no bump steer or wander at all. I took it on the highway and hit 100mph (shhhh don't tell!) and it runs hands off with a 2% crossfall on the road. Thats awesome for our 40+ year old cars! This is with 255/60 BFGs all around.
The total cost was a whopping $90 plus tax.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
As I pushed the reply button to cagotzmann I said maybe it's time to find a new shop. I did speak with a corvette shop earlier this week and I have concerns bringing it there; he said caster can be off a bit and it's acceptable. Not what I wanted to hear and they are 30 miles away.
I checked the rear camber strut dimension last month though I only used a tape measure. As I recall it was within a 1/32-1/16. Maybe I should have measured with a vernier.
I checked the rear camber strut dimension last month though I only used a tape measure. As I recall it was within a 1/32-1/16. Maybe I should have measured with a vernier.
In reality, perfect alignment relative to desired specs isn't something that can always be achieved. So, IMHO it depends a lot on just what is meant by "off a bit", as well as just how close to those specs one's purposes might demand, whether or not to keep looking.
As for "D" height, the measurement you've provided is near enough to indicate that you're apparently running very low, and in fact well below even race-prep recommendations from a geometry standpoint. Plugging in the 1/32" D figure, and assuming that you haven't lowered your camber bracket or inner strut bolt heights (i.e. via VBP smartstruts) relative to the diff, your inner u-joints are likely about 1.3" below the outers.
This would put you well into adverse toe-steer territory as your rear suspension travels further into bump, since even with the left side's .21* toe-in evenly applied you'd be approaching a whopping 1/8" toe-out per side at 1" bump or squat from static relative to chassis CL. Increasing to ~.27* per side would give you roughly 1/4" total static toe-in, but even then you'd still have 1/16" or more toe-out per side at 1" bump or squat. And, these figures don't account for TA bushing compliance. So, we definitely need to double check that you have correctly measured your D's.
FWIW, if those D's are indeed correct, the easiest fix would be to crank in that .27* on each side (beyond which I have a hard time recommending due to increasing scrub induced) and to raise your rear D to at least 1". Even so, you'd still get into toe-out beyond 1" squat or bump. Raising the diff in the chassis would buy back most of that amount (cosmetically), and get you fairly close visually to where you are now, if you're game.
Ontario73, not flaming you, but bumpsteer is a geometric function of the relationship between tie-rod lengths, toe-rod end locations, CA shafts and ball joints, and cannot be dialed out during a conventional alignment. Blocks are available which improve bumpsteer on lowered C2/C3s, but to virtually eliminate it altogether entails a bit more work.
Last edited by TheSkunkWorks; Sep 19, 2014 at 03:47 PM.
Thread Starter
Instructor
Joined: May 2013
Posts: 158
Likes: 1
From: Ct
In reality, perfect alignment relative to desired specs isn't something that can always be achieved. So, IMHO it depends a lot on just what is meant by "off a bit", as well as just how close to those specs one's purposes might demand, whether or not to keep looking.
As for "D" height, the measurement you've provided is near enough to indicate that you're apparently running very low, and in fact well below even race-prep recommendations from a geometry standpoint. Plugging in the 1/32" D figure, and assuming that you haven't lowered your camber bracket or inner strut bolt heights (i.e. via VBP smartstruts) relative to the diff, your inner u-joints are likely about 1.3" below the outers.
This would put you well into adverse toe-steer territory as your rear suspension travels further into bump, since even with the left side's .21* toe-in evenly applied you'd be approaching a whopping 1/8" toe-out per side at 1" bump or squat from static relative to chassis CL. Increasing to ~.27* per side would give you roughly 1/4" total static toe-in, but even then you'd still have 1/16" or more toe-out per side at 1" bump or squat. And, these figures don't account for TA bushing compliance. So, we definitely need to double check that you have correctly measured your D's.
FWIW, if those D's are indeed correct, the easiest fix would be to crank in that .27* on each side (beyond which I have a hard time recommending due to increasing scrub induced) and to raise your rear D to at least 1". Even so, you'd still get into toe-out beyond 1" squat or bump. Raising the diff in the chassis would buy back most of that amount (cosmetically), and get you fairly close visually to where you are now, if you're game.
Ontario73, not flaming you, but bumpsteer is a geometric function of the relationship between tie-rod lengths, toe-rod end locations, CA shafts and ball joints, and cannot be dialed out during a conventional alignment. Blocks are available which improve bumpsteer on lowered C2/C3s, but to virtually eliminate it altogether entails a bit more work.
As for "D" height, the measurement you've provided is near enough to indicate that you're apparently running very low, and in fact well below even race-prep recommendations from a geometry standpoint. Plugging in the 1/32" D figure, and assuming that you haven't lowered your camber bracket or inner strut bolt heights (i.e. via VBP smartstruts) relative to the diff, your inner u-joints are likely about 1.3" below the outers.
This would put you well into adverse toe-steer territory as your rear suspension travels further into bump, since even with the left side's .21* toe-in evenly applied you'd be approaching a whopping 1/8" toe-out per side at 1" bump or squat from static relative to chassis CL. Increasing to ~.27* per side would give you roughly 1/4" total static toe-in, but even then you'd still have 1/16" or more toe-out per side at 1" bump or squat. And, these figures don't account for TA bushing compliance. So, we definitely need to double check that you have correctly measured your D's.
FWIW, if those D's are indeed correct, the easiest fix would be to crank in that .27* on each side (beyond which I have a hard time recommending due to increasing scrub induced) and to raise your rear D to at least 1". Even so, you'd still get into toe-out beyond 1" squat or bump. Raising the diff in the chassis would buy back most of that amount (cosmetically), and get you fairly close visually to where you are now, if you're game.
Ontario73, not flaming you, but bumpsteer is a geometric function of the relationship between tie-rod lengths, toe-rod end locations, CA shafts and ball joints, and cannot be dialed out during a conventional alignment. Blocks are available which improve bumpsteer on lowered C2/C3s, but to virtually eliminate it altogether entails a bit more work.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
No problem. We all make missteaks.
So, you won't be needing excessive rear toe-in if you're anywhere near standard ride height, as you don't start loosing it towards or into toe-out until after the half-shafts go level with the road. But, I would try to get rid of the thrust angle.
So, you won't be needing excessive rear toe-in if you're anywhere near standard ride height, as you don't start loosing it towards or into toe-out until after the half-shafts go level with the road. But, I would try to get rid of the thrust angle.
Pro
Joined: Apr 2013
Posts: 535
Likes: 8
From: London Ontario
Ontario73, not flaming you, but bumpsteer is a geometric function of the relationship between tie-rod lengths, toe-rod end locations, CA shafts and ball joints, and cannot be dialed out during a conventional alignment. Blocks are available which improve bumpsteer on lowered C2/C3s, but to virtually eliminate it altogether entails a bit more work.
BTW the P-40 is one of my favorite war birds. Not the fastest and lacks the fame of the P-51s and Spits, but, still an important part of history.
Thread Starter
Instructor
Joined: May 2013
Posts: 158
Likes: 1
From: Ct
No problem. We all make missteaks.
So, you won't be needing excessive rear toe-in if you're anywhere near standard ride height, as you don't start loosing it towards or into toe-out until after the half-shafts go level with the road. But, I would try to get rid of the thrust angle.
So, you won't be needing excessive rear toe-in if you're anywhere near standard ride height, as you don't start loosing it towards or into toe-out until after the half-shafts go level with the road. But, I would try to get rid of the thrust angle.
Will the new alignment contribute to wandering? If not is it possible the power steering control valve is out of adj. What sensation would it exhibit?
Melting Slicks
Joined: Feb 2004
Posts: 2,111
Likes: 32
From: Damascus MD
Alignment
I just drove the car for the first time since the 3rd alignment. As I pass over an irregularity in the asphalt the car's tracking becomes distorted. The best way to describe the sensation I felt is; In the early 70's I had a volks bug with bias ply's., it would follow any irregularity in the road moving the car left or right especially on a concrete highway when changing lanes.
Will the new alignment contribute to wandering? If not is it possible the power steering control valve is out of adj. What sensation would it exhibit?
Will the new alignment contribute to wandering? If not is it possible the power steering control valve is out of adj. What sensation would it exhibit?
IMHO it sounds like maybe the steering box is not right. Having mine rebuilt correctly was the single biggest improvement in the handling on my 70 L46. Mine did the same thing.
If the rear feels loose I would start to look at strut rod bushings and stub axle play in the differential.
I also found that if they did not assemble the rear camber with the correct washers that it would not stay in alignment.
Bill