[C2] Caster
Thread Starter
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
Caster
I've watched a couple of videos on how to measure and adjust camber but none of them were C2s. Can someone tell me how to measure and adjust caster on a C2? Is it even possible on these cars? I have a no-return-to-center situation and before I send the steering box off to have it adjusted I want to make sure the caser angle is correct.
Race Director
Joined: Feb 2007
Posts: 15,422
Likes: 8,873
From: northern california
C2 of Year Finalist (track prepared) 2019
To measure caster yourself, you need a caster/camber guage and a set of turn plates. You've seen these gauges, no doubt. They magnetically attach to the front wheel hub. In use, you turn the front wheels 20 degrees one way, re-zero a measurement (going from memory), then return to center and read caster off a bubble level.
However, any alignment shop can measure, report, and adjust caster.
However, any alignment shop can measure, report, and adjust caster.
Last edited by jim lockwood; Mar 29, 2022 at 07:35 PM.
Race Director
Joined: Jan 2003
Posts: 17,658
Likes: 3,665
From: Central Arkansas
You can measure or at least evaluate camber on a level surface with a level but not caster. As Jim said you can get a camber/caster gage unit for home alignment. Turn plates are nice. A pretty level piece of pavement or floor is necessary. Do you have power or manual steering.
Safety Car
Joined: Feb 2006
Posts: 4,142
Likes: 704
Speedway Motors sells an "Economy" caster/camber gauge, about $45.00. It's pretty easy to use and pays for itself.
Speedway Economy Caster/Camber Suspension Gauge Tool (speedwaymotors.com)
Speedway Economy Caster/Camber Suspension Gauge Tool (speedwaymotors.com)
Le Mans Master
Joined: Sep 2008
Posts: 5,662
Likes: 2,344
From: Lake Minnetonka, Mn
2018 C1 of Year Finalist
To measure caster yourself, you need a caster/camber guage and a set of turn plates. You've seen these gauges, no doubt. They magnetically attach to the front wheel hub. In use, you turn the front wheels 20 degrees one way, re-zero a measurement (going from memory), then return to center and read caster off a bubble level.
However, any alignment shop can measure, report, and adjust caster.
However, any alignment shop can measure, report, and adjust caster.
Jim is dead on. I wouldn't reinvent the wheel here. Having owned countless Corvettes for over a 50 yr. period, I can't remember the last time I had to perform an alignment. A good front-end person, when having the car on the rack, can also diag other issues that you might not be aware of.
Thread Starter
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
Dan, you used the phrase "A good front-end person", I might as well look for a unicorn. I had it aligned but the "Old guy" was about 40 years old, claimed he knew old classic cars. He didn't. I'll look around some more but it is getting hard to find anyone who works ao anything that isn't computer driven.
Team Owner
Joined: Sep 2002
Posts: 38,316
Likes: 2,071
From: California
Some of the Chevrolet Dealerships have the service lane, you park it in the square and they laser it, have a print out. They so enjoyed seeing the old Vette, they charged nothing.
Or you can buy gauges like I have, others have.
Or you can buy gauges like I have, others have.
Melting Slicks
Joined: Mar 2004
Posts: 2,964
Likes: 419
From: Melbourne FL
While you're looking to determine your caster, I offer a bit of advice from John Z some years ago - with modern radials try to get close to 4 degrees as you can for better drivability. The original spec was more conservative and intended for bias ply tires. And there's a local shop that can do old vettes but the owner injured his should last fall and hasn't called me back yet about doing mine so he may have just quit! He's probably my age or older so it wouldn't surprise me if he's decided to hang it up.
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Drifting
Joined: Nov 2016
Posts: 1,958
Likes: 577
From: Pittsburgh PA
caster is adjusted by adding shims to the rear, or removing from front. caster adjustments will affect camber. i think you can move shims from front to rear to increase caster with minimal affect on camber.
agree you want more caster with radials than OE specs. however i dont know if you can get to 4 with stock unmodified arms. I think I was only able to get to like 3 with mine.
agree you want more caster with radials than OE specs. however i dont know if you can get to 4 with stock unmodified arms. I think I was only able to get to like 3 with mine.
Le Mans Master
Joined: Sep 2008
Posts: 5,662
Likes: 2,344
From: Lake Minnetonka, Mn
2018 C1 of Year Finalist
Dan, you used the phrase "A good front-end person", I might as well look for a unicorn. I had it aligned but the "Old guy" was about 40 years old, claimed he knew old classic cars. He didn't. I'll look around some more but it is getting hard to find anyone who works ao anything that isn't computer driven.
Racer
Joined: Jul 2018
Posts: 429
Likes: 85
Front wheel alignment
Power steering
Camber 0
Caster 2.5 If you can get it to 3 great, but usually about 2.5 is all you can get out of it and it will track very well with 2.5
Toe 1/32 (for total toe of 1/16)
for manual steering go for 1.75 camber. Any more than that and the wheel is to heavy.
You can set it yourself but you need a really level floor. I took two vinyl tiles and put grease in between then to serve as turn plates, it worked great.
Power steering
Camber 0
Caster 2.5 If you can get it to 3 great, but usually about 2.5 is all you can get out of it and it will track very well with 2.5
Toe 1/32 (for total toe of 1/16)
for manual steering go for 1.75 camber. Any more than that and the wheel is to heavy.
You can set it yourself but you need a really level floor. I took two vinyl tiles and put grease in between then to serve as turn plates, it worked great.
Instructor
Joined: Oct 2014
Posts: 130
Likes: 30
From: San Jose CA
Tiger Joe is right about the Caster adjustment. It is conducted by measuring camber with the wheels straight and then turned to 20 degrees (or so) away from the car. I did not use the turn plates Jim mentioned which the friction caused will induce error but for your purpose might be OK, it worked for me. I cut a piece of 1x1 wood to the diameter of the rim and notched the center to clear the wheel bearing cap. I used and angle finder app on my smart phone to measure camber. Then I used the simplified formula to find the caster:
Here is an excerpt from a website for the procedure I used:
1. Turn 20 degrees left of center and take a camber reading.
2. Turn 20 degrees right of center and take a camber reading.
3. Take the difference and multiply by 1.5, that is your castor. i.e. left reading +1, right reading +4. Difference =3 x 1.5 = 4.5 deg positive castor.
https://www.apexspeed.com/forums/sho...itive%20castor.
I was able to solve my "return to center problem" using this method. There is a more complex formula that uses trigonometry , will be more accurate but since I am using sticks, cell phone and no turn plate I avoided it:
https://motoiq.com/wrench-tip-how-to...n-alignment/3/
Good luck!
Here is an excerpt from a website for the procedure I used:
1. Turn 20 degrees left of center and take a camber reading.
2. Turn 20 degrees right of center and take a camber reading.
3. Take the difference and multiply by 1.5, that is your castor. i.e. left reading +1, right reading +4. Difference =3 x 1.5 = 4.5 deg positive castor.
https://www.apexspeed.com/forums/sho...itive%20castor.
I was able to solve my "return to center problem" using this method. There is a more complex formula that uses trigonometry , will be more accurate but since I am using sticks, cell phone and no turn plate I avoided it:
https://motoiq.com/wrench-tip-how-to...n-alignment/3/
Good luck!
Race Director
Joined: Nov 2000
Posts: 10,340
Likes: 664
From: Beverly Hills (Pine Ridge) Florida
Even a couple of 12" squares of wax paper on top of each other, under each front tire, can act as a "turn plate"...
Not ideal, but in a pinch...
And I gave up on "alignment shops", for the older cars years ago. They are fine for the most part for newer vehicles, but don't ever get an alignment on anything late on a Friday.
Plasticman
Not ideal, but in a pinch...
And I gave up on "alignment shops", for the older cars years ago. They are fine for the most part for newer vehicles, but don't ever get an alignment on anything late on a Friday.
Plasticman
Thread Starter
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
Thank you all for your ideas. I do have electric power steering so turning won't be an issue. I am not trying to align my car myself only to see if the caster is in the ballpark. Right now my car drives very well with zero lash but no return to center. Can someone please explain how removing or adding shims to the upper arm pivot can change the caster? I can see how it would change the camber but I'm lost on it changing the caster.
Le Mans Master
Joined: May 2005
Posts: 7,344
Likes: 2,272
From: Central Maryland
Adding shims to the rear, and/or subtracting them from the front, of the upper control arm, will rotate the arm a few degrees, moving the upper ball joint rearward, and adding caster. Obviously, doing the inverse with shims will rotate the upper ball joint forward, and reduce caster.
Adding or removing shims equally from the front and rear will adjust camber only.
Live well,
SJW
Adding or removing shims equally from the front and rear will adjust camber only.
Live well,
SJW
Drifting
Joined: Oct 2008
Posts: 1,936
Likes: 92
From: Rochester Hills Michigan
There are 2 alignment parameters that return your steering to center: steering axis inclination and caster. Steering axis inclination should be enough to return your steering to center even with low caster. Too much friction in the steering system can cause a lack of returnability. I think your electric steering may be adding too much friction...? I would make sure your ball joints are well lubricated too. Tell your alignment technician about the returnability problem.
Drifting
Joined: May 2013
Posts: 1,989
Likes: 455
From: Texas
Here's a good description and sequence for checking.
https://www.hendersonslineup.com/steering-returnability
Steve
https://www.hendersonslineup.com/steering-returnability
Steve
Team Owner
Joined: Sep 2002
Posts: 38,316
Likes: 2,071
From: California
There are 2 alignment parameters that return your steering to center: steering axis inclination and caster. Steering axis inclination should be enough to return your steering to center even with low caster. Too much friction in the steering system can cause a lack of returnability. I think your electric steering may be adding too much friction...? I would make sure your ball joints are well lubricated too. Tell your alignment technician about the returnability problem.
Team Owner
Joined: Sep 2002
Posts: 38,316
Likes: 2,071
From: California
Adding shims to the rear, and/or subtracting them from the front, of the upper control arm, will rotate the arm a few degrees, moving the upper ball joint rearward, and adding caster. Obviously, doing the inverse with shims will rotate the upper ball joint forward, and reduce caster.
Adding or removing shims equally from the front and rear will adjust camber only.
Live well,
SJW
Adding or removing shims equally from the front and rear will adjust camber only.
Live well,
SJW
Thread Starter
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
I too was concerned about the electric power steering being the culprit but unlike hydraulic PS, I can turn it off and there is no effect or drag on the steering system. I have done this on the road and it didn't help the issue. I have planned to send the gearbox to Gary but wanted to be sure that it was the problem before spending big bucks on the box. When I had it aligned last year, the right control arm, front bolt ran out of shimable threads to reach the desired setting. I have '65 disc brakes on the front but that was done when there was no return-to-center already.