[ANSWERED] Eccentric Bolts vs Camber Plates
06-10-2015, 09:50 AM
#1
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[ANSWERED] Eccentric Bolts vs Camber Plates
Original question is here.
jvp asked:
Has your team considered replacing the Corvette LCA eccentric bolts with camber plates, and handling camber and caster with shims on the UCA? It might make alignments take a bit longer the first time, but they'd hold more solidly for those of us that like to track our cars.
Has your team considered replacing the Corvette LCA eccentric bolts with camber plates, and handling camber and caster with shims on the UCA? It might make alignments take a bit longer the first time, but they'd hold more solidly for those of us that like to track our cars.
Tadge answered:
At the Bowling Green assembly plant, a new Corvette comes off the line every 3 minutes. We custom align every car very precisely – it is super important on a car with such high performance tires and customer expectations. Cam bolts are infinitely adjustable within their range. Cams provide the most productive method of giving the best adjustment every time accounting for any body and cradle assembly dimensional variation.
The front upper control arm is very symmetric, so using the lower control arm is better for independent camber and caster adjustment. We adjust camber with the cross car part of the arm (handling bushing), and the caster adjustment with the more fore/aft part of the arm (ride bushing). Also, the spread between the bushings is bigger on the bottom which allows for finer adjustments.
The rear upper control arm is not symmetric. So there could be some benefit to use the upper versus the lower arm which is symmetric for camber vs. caster adjustment. However, the larger spread is still better on the lower control arm. Upper control arm washers are used to make big nominal shifts in camber. It allowed for minimizing the cam bolt size/travel required and permitted us to have different nominal camber settings between Stingray/Z51, and Z06. There have been some observers surprised that we have adjustments for rear caster. We use that to make sure we don’t have rear caster contributing to rear ride steer.
At the Bowling Green assembly plant, a new Corvette comes off the line every 3 minutes. We custom align every car very precisely – it is super important on a car with such high performance tires and customer expectations. Cam bolts are infinitely adjustable within their range. Cams provide the most productive method of giving the best adjustment every time accounting for any body and cradle assembly dimensional variation.
The front upper control arm is very symmetric, so using the lower control arm is better for independent camber and caster adjustment. We adjust camber with the cross car part of the arm (handling bushing), and the caster adjustment with the more fore/aft part of the arm (ride bushing). Also, the spread between the bushings is bigger on the bottom which allows for finer adjustments.
The rear upper control arm is not symmetric. So there could be some benefit to use the upper versus the lower arm which is symmetric for camber vs. caster adjustment. However, the larger spread is still better on the lower control arm. Upper control arm washers are used to make big nominal shifts in camber. It allowed for minimizing the cam bolt size/travel required and permitted us to have different nominal camber settings between Stingray/Z51, and Z06. There have been some observers surprised that we have adjustments for rear caster. We use that to make sure we don’t have rear caster contributing to rear ride steer.
06-10-2015, 07:44 PM
#3
Burning Brakes
Great question and a GREAT answer. This should be Tech sticky.
Thanks!
Thanks!
06-10-2015, 08:20 PM
#4
Safety Car
I see one point being made. Bolts offer continuous adjustment whereas plates offer discrete adjustment. In other words, there is fine tuning possible with the bolts whereas the adjustment with the plates is a little coarse.
Example: Camber desired at -2.0. Bolts allow -2.0 whereas plates may have to be -1.9 or -2.1.
Can anyone confirm this is the basic message?
Example: Camber desired at -2.0. Bolts allow -2.0 whereas plates may have to be -1.9 or -2.1.
Can anyone confirm this is the basic message?
06-10-2015, 10:46 PM
#5
Race Director
I see one point being made. Bolts offer continuous adjustment whereas plates offer discrete adjustment. In other words, there is fine tuning possible with the bolts whereas the adjustment with the plates is a little coarse.
Example: Camber desired at -2.0. Bolts allow -2.0 whereas plates may have to be -1.9 or -2.1.
Can anyone confirm this is the basic message?
Example: Camber desired at -2.0. Bolts allow -2.0 whereas plates may have to be -1.9 or -2.1.
Can anyone confirm this is the basic message?
Camber plates aren't adjustable, to adjust, you'd have to use shims. Much slower to assemble, as you have to install, measure, disassemble, install again with shims, measure again, etc. But once set, that alignment is more solid.
06-11-2015, 12:07 AM
#6
Team Owner
i should get my NASCAR Crew chief brother in on this stuff!
Original question is here.
I think the last comment rear ride steer should be switched to ride stability whether that be going straight or turning!
Because of the spring and control arm tracking , etc etc. etc. I think plates on the bottom or shims in thin increment would be more solid of a platform and you could dial in the upper with eccentricly bushings and slots for sliding the assembly if your heart has to have settings more so in the radical limits of the wheelwells. I assume the design based on tire size and wheelwell and just geometry is fairly refined in the inherent design, so I wouldn't think the car would need a radical range of castor adjustability from the top anyways and the bottom being wider is definitely more limited so range limiting envelope of eccentric cams, bolts or bushings or such seems like a sells pitch!
Adding castor to the rear seems like a plus for front to rear weighting and all of the characteristic that come with anti-squat or brake jacking way more than steer? Steer in the rear is a defect!!!!!!!! Because you actually dont have steer control connected back there!!!! Sounds overall, like a bunch of mumbo jumbo!!!! It could make steering in the front less heavy (but you guys have power steering anyways in your modern ones
), by gains from the back, but not cause steer directly, but lead to steer tracking to center 
I need to look of the range of castor spec on these modern cars!
Last edited by TCracingCA; 06-11-2015 at 01:19 AM.
06-11-2015, 06:22 AM
#8
Basically Tadge said it is quicker to use eccentrics than plates with holes to adjust alignment, and of course it makes it possible to get the alignment much closer to a design target than do camber plates and washers. But that is simply an evident statement as anyone who has ever aligned a car would already know that. He didn't go to the crux of that matter which is using plates to align the car for the track. He just talked about the production line need for quick, precise adjustment. The idea with camber plates is that you get a coarse fixed adjustment on the bottom arm and then fine tune with the upper arm using shims. No one would expect this to be a production or standard alignment shop technique. Just had a friend take his Z06 for an alignment and shop refused to take out the OEM washers under the upper A-arm for a track alignment, because they just didn't want to do that. Camber plates would just be for hard core track guys.
As for ride steer in the rear, my take is that he means bump steer which is when the toe changes as the suspension moves up and down, which destabilizes the car. Bump steer can occur to either front or rear wheels, since the toe arm length is fixed and it has a hold on the end of the knuckle/upright. If the geometry is wrong, as the wheel moves up and down it can rotate and steer in an unwanted direction. Caster is spec'ed out at 0.0 degrees in the rear for all C7's, and one can imagine that if it is off that at say 2.0 degrees, then it might toe in or toe out as the rear suspension moves up and down. Another effect might be castor trail which is usually only referred to in relation to the front suspension, where the line between the upper and lower ball joints points ahead or in front of the centre of the contact patch. The distance between the lines at the ground determine a lever arm length which acts to torque the wheel due to grip force when car is steered. Of course rear is not steered on the C7 (new GT3's are), but if there is bump steer in the rear, then there might be an effect. Not clear on what effect that might have on ride steer.
But here is the funny thing with their eccentric adjusters. I have never seen an alignment shop that measures caster on the rear of the car. GM manual shows how to measure rear caster with an add-on digital angle gauge that is not connected to the alignment machine, and that is why virtually no shops measure it. I have never seen a print-out from an alignment machine that shows rear caster setting, although there may be some, just not in my neck of the woods. I was just at my GM dealer yesterday and I happened to ask the shop foreman if they had any plans to upgrade their old alignment machine, and he said no, that's not in the budget. And no rear caster measuring either. They just send me to a shop specializing in track alignments. Of course those guys don't measure rear caster either. When I put my car on my lift at home to check the eccentrics after a track alignment (which couldn't be done properly in the rear because the toe adjuster does not have enough range to get proper toe and camber without removing washers, ughh!), on one side of the rear suspension arm the front eccentric was all the way to the max with the other one half-way, while on the other side it was the opposite. So I have the wrong caster on both rear wheels, and opposite on both rear wheels. My friend's Z06 also with a track alignment from the same shop has a different set of positions for his rear arm bottom eccentrics. Who knows what rear cater we have. My view is that if the rear caster is so important to these cars as Tadge had it fixed for the "re-match" at Big Willow with the Nismo GT-R, then they should have forced dealers to adjust rear caster, or had a suspension design where you couldn't get it wrong by adjusting camber. As it stands I would imagine that 99% of C7's that have had a rear alignment have the wrong caster in the rear.
For the GT-R which I also happen to own, Nissan forced all dealers selling the GT-R to have their techs and shop managers go through special training to be able to sell the car (I saw some of the training videos), and they also forced them to buy a special alignment machine and other shop equipment. GM did not of course do that. I asked my dealer.
I have to say that I appreciate Tadge responding to our forum questions, as there is always something to be learned from his responses. It's just that sometimes some of us don't quite always get the response we were hoping for, or at least not all of it. Let's keep it coming.
As for ride steer in the rear, my take is that he means bump steer which is when the toe changes as the suspension moves up and down, which destabilizes the car. Bump steer can occur to either front or rear wheels, since the toe arm length is fixed and it has a hold on the end of the knuckle/upright. If the geometry is wrong, as the wheel moves up and down it can rotate and steer in an unwanted direction. Caster is spec'ed out at 0.0 degrees in the rear for all C7's, and one can imagine that if it is off that at say 2.0 degrees, then it might toe in or toe out as the rear suspension moves up and down. Another effect might be castor trail which is usually only referred to in relation to the front suspension, where the line between the upper and lower ball joints points ahead or in front of the centre of the contact patch. The distance between the lines at the ground determine a lever arm length which acts to torque the wheel due to grip force when car is steered. Of course rear is not steered on the C7 (new GT3's are), but if there is bump steer in the rear, then there might be an effect. Not clear on what effect that might have on ride steer.
But here is the funny thing with their eccentric adjusters. I have never seen an alignment shop that measures caster on the rear of the car. GM manual shows how to measure rear caster with an add-on digital angle gauge that is not connected to the alignment machine, and that is why virtually no shops measure it. I have never seen a print-out from an alignment machine that shows rear caster setting, although there may be some, just not in my neck of the woods. I was just at my GM dealer yesterday and I happened to ask the shop foreman if they had any plans to upgrade their old alignment machine, and he said no, that's not in the budget. And no rear caster measuring either. They just send me to a shop specializing in track alignments. Of course those guys don't measure rear caster either. When I put my car on my lift at home to check the eccentrics after a track alignment (which couldn't be done properly in the rear because the toe adjuster does not have enough range to get proper toe and camber without removing washers, ughh!), on one side of the rear suspension arm the front eccentric was all the way to the max with the other one half-way, while on the other side it was the opposite. So I have the wrong caster on both rear wheels, and opposite on both rear wheels. My friend's Z06 also with a track alignment from the same shop has a different set of positions for his rear arm bottom eccentrics. Who knows what rear cater we have. My view is that if the rear caster is so important to these cars as Tadge had it fixed for the "re-match" at Big Willow with the Nismo GT-R, then they should have forced dealers to adjust rear caster, or had a suspension design where you couldn't get it wrong by adjusting camber. As it stands I would imagine that 99% of C7's that have had a rear alignment have the wrong caster in the rear.
For the GT-R which I also happen to own, Nissan forced all dealers selling the GT-R to have their techs and shop managers go through special training to be able to sell the car (I saw some of the training videos), and they also forced them to buy a special alignment machine and other shop equipment. GM did not of course do that. I asked my dealer.
I have to say that I appreciate Tadge responding to our forum questions, as there is always something to be learned from his responses. It's just that sometimes some of us don't quite always get the response we were hoping for, or at least not all of it. Let's keep it coming.
Last edited by descartesfool; 06-11-2015 at 06:30 AM.
06-11-2015, 07:06 AM
#9
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Since the measurement of rear caster requires a angle bracket that is bolted to the knuckle and a digital angle measurement gauge that is magnetically attached to the bracket a shop doesn't need to upgrade its alignment machine. The only issues would be the price they get charged by GM for a $5 bracket and a $100 gauge. All the mechanic needs to do is make sure the caster is correct and note it on the printout by hand. Not a big deal other than making the adjustments to get it correct. The mechanic has to be under the car to adjust the camber so it isn't that much extra effort to monitor two displays Vs one.
Bill
Bill
06-11-2015, 08:38 AM
#10
Burning Brakes
. . . . . . . Who knows what rear cater we have. My view is that if the rear caster is so important to these cars as Tadge had it fixed for the "re-match" at Big Willow with the Nismo GT-R, then they should have forced dealers to adjust rear caster, or had a suspension design where you couldn't get it wrong by adjusting camber. As it stands I would imagine that 99% of C7's that have had a rear alignment have the wrong caster in the rear.
I have to say that I appreciate Tadge responding to our forum questions, as there is always something to be learned from his responses. It's just that sometimes some of us don't quite always get the response we were hoping for, or at least not all of it. Let's keep it coming.
I have to say that I appreciate Tadge responding to our forum questions, as there is always something to be learned from his responses. It's just that sometimes some of us don't quite always get the response we were hoping for, or at least not all of it. Let's keep it coming.
06-11-2015, 12:56 PM
#11
Team Owner
First i appreciate having a car's engineer talking with us
I live in the C2/C3 world, but run CVC-apex multi-link in the back of one car and a Guldstrand multi-link in the back of the other!
These new cars do handle pretty nice, but I have been around enough to know for track or race usage you have to throw the usual tricks and trick parts probably at them.
I should grab a performance suspension catalog for these and see what goodies are being sold to upgrade the handling, because that would tell me where people think the mods should be to race track them.
Bump steer and toe steer etc. used to be big problems in my generation of chosen ride, but my set ups give rear castor adjustment and better address to give easy adjustment ability eliminating the trad-ish shims, bump is better addressed and at 3" of travel basically non-existent, etc.. For these new cars I would think all of these issues would be dialed out by engineers by now, but giving an adjustment range to tune for wear or ride preference for a true enthusiast. And I thought the fancy buttons or ***** did all of this adjustment for you guys, so you wouldn't have to get your hands dirty!
I guess because they are meant to be operated on the street and in consideration of the road, they still have to provide all kinds of suspension travel (pushing out to off road ranges, "due to poor roads" and customer expectations) , which can play havoc related to bump steer, toe steer, camber movement, etc. I have about for my cars limited it to about 3 inches of suspension travel, so i just skip over extra large potholes and hope i don't break a heim, and i slow way down for bumps, so i don't sheer a heim or crunch my oversized low oil pan, or end up getting hung up by the rockers (ran aground)!!! I only truly bottomed it out with my heavy springs badly, when I mis-judged a long sweep turn and rode up over the actual curb (darn understeer)!
Therefore because ride comfort has to exist because of the soft a$$ enthusiasts wanting cake and ice cream in their ride quality, where do you draw the limit for a performance car related to suspension travel. It is sad that people buy these cars with handling capability that the average enthusiasts will never explore or be capable of exploring! Thus i assume the Z-06 and other handling sharks are offered for those that can explore, but then Joe Rich guy wants to buy a label (z-06) and then complains that his backside is sore from the boo hoo harsh ride!
i am getting closer to putting my C2 back on the road, and handling wise i have always held my own in comparison to every subsequent Corvette generation, so i am now studying my new enemies C6/C7 cars. I love and hate that in the street enviroment these cars can walk away from me, because i have to be careful not to lunch a heim or can't get decent street speed rated rubber in my wide tire sizes that have been replaced by DONK rims and tires, but god help them on a decent road within my suspension travel or on the track still with race rubber. I was running Willow Springs in the 1:28/29 and these new cars are doing that now! Frustrating, but it is a credit to the engineers, but then again it is my brakes that disadvantage me!
It was the quick castor related to steer that jumped out at me, and doing the fine castor adjustments while lying on your back under the car, when on our Corvettes we adjust castor standing up! I personally think most everyone can get the front end handling ironed out, but back end alignment expertise is what separates the men from the boys and can win races!
I did like the race tired ringer Z-28 beating the 911. Keep them scratching their heads!
I am gearing up for LeMans and i hope the Z-07's are sandbagging!
These new cars do handle pretty nice, but I have been around enough to know for track or race usage you have to throw the usual tricks and trick parts probably at them.
I should grab a performance suspension catalog for these and see what goodies are being sold to upgrade the handling, because that would tell me where people think the mods should be to race track them.
Bump steer and toe steer etc. used to be big problems in my generation of chosen ride, but my set ups give rear castor adjustment and better address to give easy adjustment ability eliminating the trad-ish shims, bump is better addressed and at 3" of travel basically non-existent, etc.. For these new cars I would think all of these issues would be dialed out by engineers by now
, but giving an adjustment range to tune for wear or ride preference for a true enthusiast. And I thought the fancy buttons or ***** did all of this adjustment for you guys, so you wouldn't have to get your hands dirty! I guess because they are meant to be operated on the street and in consideration of the road, they still have to provide all kinds of suspension travel (pushing out to off road ranges, "due to poor roads" and customer expectations) , which can play havoc related to bump steer, toe steer, camber movement, etc. I have about for my cars limited it to about 3 inches of suspension travel, so i just skip over extra large potholes and hope i don't break a heim, and i slow way down for bumps, so i don't sheer a heim or crunch my oversized low oil pan, or end up getting hung up by the rockers (ran aground)!!! I only truly bottomed it out with my heavy springs badly, when I mis-judged a long sweep turn and rode up over the actual curb (darn understeer)!
Therefore because ride comfort has to exist because of the soft a$$ enthusiasts wanting cake and ice cream in their ride quality, where do you draw the limit for a performance car related to suspension travel. It is sad that people buy these cars with handling capability that the average enthusiasts will never explore or be capable of exploring! Thus i assume the Z-06 and other handling sharks are offered for those that can explore, but then Joe Rich guy wants to buy a label (z-06) and then complains that his backside is sore from the boo hoo harsh ride!
i am getting closer to putting my C2 back on the road, and handling wise i have always held my own in comparison to every subsequent Corvette generation, so i am now studying my new enemies C6/C7 cars. I love and hate that in the street enviroment these cars can walk away from me, because i have to be careful not to lunch a heim or can't get decent street speed rated rubber in my wide tire sizes that have been replaced by DONK rims and tires, but god help them on a decent road within my suspension travel or on the track still with race rubber. I was running Willow Springs in the 1:28/29 and these new cars are doing that now! Frustrating, but it is a credit to the engineers, but then again it is my brakes that disadvantage me!
It was the quick castor related to steer that jumped out at me, and doing the fine castor adjustments while lying on your back under the car, when on our Corvettes we adjust castor standing up!
I personally think most everyone can get the front end handling ironed out, but back end alignment expertise is what separates the men from the boys and can win races!I did like the race tired ringer Z-28 beating the 911. Keep them scratching their heads!
I am gearing up for LeMans and i hope the Z-07's are sandbagging!
Last edited by TCracingCA; 06-11-2015 at 04:19 PM.
06-11-2015, 01:52 PM
#13
Safety Car
Eccentric bolts provide the ability to infinitely adjust the joint within their range. And much faster to adjust on assembly line. Just turn to adjust. But under high loads and vibration, if they turn after installed, then the car goes out of alignment.
Camber plates aren't adjustable, to adjust, you'd have to use shims. Much slower to assemble, as you have to install, measure, disassemble, install again with shims, measure again, etc. But once set, that alignment is more solid.
Camber plates aren't adjustable, to adjust, you'd have to use shims. Much slower to assemble, as you have to install, measure, disassemble, install again with shims, measure again, etc. But once set, that alignment is more solid.
The second and third paragraphs seem to just describe the current suspension geometry and adjustment menthod. One benefit I see is that we can show this response to alignment shops so they are more willing to change the upper control arm washers and rear caster.
06-11-2015, 05:23 PM
#14
Burning Brakes
But here is the funny thing with their eccentric adjusters. I have never seen an alignment shop that measures caster on the rear of the car. GM manual shows how to measure rear caster with an add-on digital angle gauge that is not connected to the alignment machine, and that is why virtually no shops measure it. I have never seen a print-out from an alignment machine that shows rear caster setting, although there may be some, just not in my neck of the woods. I was just at my GM dealer yesterday and I happened to ask the shop foreman if they had any plans to upgrade their old alignment machine, and he said no, that's not in the budget. And no rear caster measuring either. They just send me to a shop specializing in track alignments. Of course those guys don't measure rear caster either. When I put my car on my lift at home to check the eccentrics after a track alignment (which couldn't be done properly in the rear because the toe adjuster does not have enough range to get proper toe and camber without removing washers, ughh!), on one side of the rear suspension arm the front eccentric was all the way to the max with the other one half-way, while on the other side it was the opposite. So I have the wrong caster on both rear wheels, and opposite on both rear wheels. My friend's Z06 also with a track alignment from the same shop has a different set of positions for his rear arm bottom eccentrics. Who knows what rear cater we have. My view is that if the rear caster is so important to these cars as Tadge had it fixed for the "re-match" at Big Willow with the Nismo GT-R, then they should have forced dealers to adjust rear caster, or had a suspension design where you couldn't get it wrong by adjusting camber. As it stands I would imagine that 99% of C7's that have had a rear alignment have the wrong caster in the rear.
This question is probably not couched in technical terms, but my C7 seems very loose in its handling. At 1600 miles the front end darts all over the road and at highway speeds when I hit a bump the rear end will jump sideways. Alignment has been checked and is within specification for camber and toe both front and back. Caster has not been checked. Could bad caster settings cause the car to be as "squirrelly" as it feels. Something definitely feels wrong. I have never had a car feel as out of control when hitting a bump at highway speeds. Any thoughts would be greatly appreciated.
So, I called my favorite Corvette mechanic. He was able to borrow a digital angle gauge and adaptor and I took it in to him this morning. He was able to measure the rear castor at +3.2 on the rear left and -1.9 on the rear right. Numerous adjustments of the rear camber, toe and caster and he was able to get the rear caster on both sides to -0.3 on both sides. The specification is 0.0 to -0.8. Took the beauty for a test drive and the problem was gone. No more rear kicking to the right. A shout out to Corvette Care in Columbus Ohio!!!!!!!!!
Ernie
06-11-2015, 08:58 PM
#15
Team Owner
Well the first clue was
the car jumping sideways on the jump! 
So unless you are some super suspension tuner that can set Indianapolis or banked oval racers that only turns right, then the Castor should be symmetrically set "equal" on both sides front and rear. Now with those settings, no wonder it was feeling funny! I would think that would have been visible side to side, being that differently set up. But then some later model Owners probably just admire the cars as they walk up to them, front or back! And most probably might sneak up on it from the side to get in, but rarely stand back and take in the swoopey side profile and the relationship of the tires within the wheelwells!
And an alignment shop if they even were ededcated (hillbilly slang for educated) beyond the 8th grade
, should check it just because those fancy eccentrically things could have slipped back yonder.
PS it seems like east coast guys use Caster, or West Coast guys that used to be from the east coast. I still use Castor being a native Californian, so don't mind me! And even the one Western Australian guy that probably speaks closer to proper Queen's English also, was a Castor guy above.
So unless you are some super suspension tuner that can set Indianapolis or banked oval racers that only turns right, then the Castor should be symmetrically set "equal" on both sides front and rear. Now with those settings, no wonder it was feeling funny! I would think that would have been visible side to side, being that differently set up. But then some later model Owners probably just admire the cars as they walk up to them, front or back! And most probably might sneak up on it from the side to get in, but rarely stand back and take in the swoopey side profile and the relationship of the tires within the wheelwells!
And an alignment shop if they even were ededcated (hillbilly slang for educated) beyond the 8th grade
, should check it just because those fancy eccentrically things could have slipped back yonder.PS it seems like east coast guys use Caster, or West Coast guys that used to be from the east coast. I still use Castor being a native Californian, so don't mind me! And even the one Western Australian guy that probably speaks closer to proper Queen's English also, was a Castor guy above.
Last edited by TCracingCA; 06-11-2015 at 09:08 PM.
06-11-2015, 10:59 PM
#16
Soon after getting my new Z06 I did a tire temp reading and had 25-30 degree difference between the inside and outside of the tread on the rear tires. I then checked the camber and it was -2 degrees. Good for track but maybe excessive for normal driving. I set the camber to -1/2 degree and the tread temp difference dropped to a 10 degree difference. I used the eccentric bolt for adjusting and marked the original position on the washer. After reading this thread about rear caster I now realize that using the eccentric will change caster. To decrease negative camber I pulled the front of the lower A-arm in thus pulling the bottom of the wheel/tire in. But pulling the front A-arm in also will move the lower ball joint forward thus changing caster. Is my thinking correct? So to correct this I would now change washers on the upper A-arm? Or better yet do camber entirely on the upper arm. I could add washers equally to both sides of the A-arm to move the top of the tire out and then this would not change the caster.
06-11-2015, 11:48 PM
#17
Team Owner
I am trying to decide whether i actually need to know anything about the suspensions
on these newer Vettes. But the front suspension through the action of turning the car is designed for camber changes to aid the function of turning. I assume there are a-arms in the back of these new ones, but a design for the back I think could be designed with castor and camber independance! So you guys are saying these cars have adjustment that affects both in the rear? see i keep going back to the steering control thing? So have they designed in some kind of rotational, or axis, torsonal effect back there to aid the cars turning quickness?
06-12-2015, 02:25 AM
#18
Burning Brakes
Soon after getting my new Z06 I did a tire temp reading and had 25-30 degree difference between the inside and outside of the tread on the rear tires. I then checked the camber and it was -2 degrees. Good for track but maybe excessive for normal driving. I set the camber to -1/2 degree and the tread temp difference dropped to a 10 degree difference. I used the eccentric bolt for adjusting and marked the original position on the washer. After reading this thread about rear caster I now realize that using the eccentric will change caster. To decrease negative camber I pulled the front of the lower A-arm in thus pulling the bottom of the wheel/tire in. But pulling the front A-arm in also will move the lower ball joint forward thus changing caster. Is my thinking correct? So to correct this I would now change washers on the upper A-arm? Or better yet do camber entirely on the upper arm. I could add washers equally to both sides of the A-arm to move the top of the tire out and then this would not change the caster.
Ernie
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Retired 2006 (09-03-2021)
06-12-2015, 10:26 AM
#19
One of our Tech Contributors, Theta, has posted the alignment procedure here: https://www.corvetteforum.com/forums...alignment.html. You'll notice that changing either of the lower control arm eccentrics will change caster to some degree. Therefore, moving either eccentric to set rear camber will also change rear caster on that wheel. Some shops don't seem to realize this.
Ernie
Ernie
06-12-2015, 01:41 PM
#20
Burning Brakes
Those instructions are not for a C6! Look closely at the diagram. The sway bar is in front of the mufflers. And it shows a rear eccentric. On my C6 the sway bar goes under the mufflers. The rear bolt on the A-arm also attaches the sway bar clamp and there is no eccentric.
Ernie