Castor with new control arms
Thread Starter
Racer
Joined: Jan 2017
Posts: 496
Likes: 153
From: San Francisco Bay Area
Castor with new control arms
Guys I have just come back from having my car aligned by a reputable alignment shop in the area that was recommended by a Corvette repair shop. On my 72 I have semi coil overs and newly installed Global West upper control arms. (They are beautiful pieces). I have a Borgeson steering box and all new front end components and bushings. Per the specifications provided by Van Steel, I requested the shop to dial in 6-8 degrees of positive castor. They documented 3.86 positive for driver's side and 4.21 positive for passenger side. They indicated that was as much as they could get. I'm confused as to how that would be possible if the control arms themselves have an additional 5 degrees built in. Any clarification for the remedial reading crowd as I am thoroughly confused.
Thanks much.
Thanks much.
Racer
Joined: Apr 2009
Posts: 330
Likes: 44
From: Cincinnati Ohio
They probably had to do that to get the proper camber settings. The camber is more important than the castor setting. Go back and talk to the alignment shop, they should be able to explain it to you. I have Global West arms on my 73 we had difficulty getting proper camber settings without much higher castor readings, I am around 6 on each side. Was even considering putting spreader bar between the front upper A Arm mounts.
Last edited by RU7376vettes; Aug 31, 2020 at 04:46 PM.
Race Director
Joined: Mar 2017
Posts: 11,797
Likes: 4,420
From: Virginia
They probably had to do that to get the proper camber settings. The camber is more important than the castor setting. Go back and talk to the alignment shop, they should be able to explain it to you. I have Global West arms on my 73 we had difficulty getting proper camber settings without much higher castor readings, I am around 6 on each side. Was even considering putting spreader bar between the front upper A Arm mounts.
These arms (SPC Adjustables) allow you to add both camber and caster, since you can increase the length of the front leg of the triangle.
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 592
I have these same upper arms, I run - 3.6 degrees camber and 6 degrees caster (track days). This was not possible with any other upper arms.
Because the global west arms are fixed lengths the amount of camber you get varies car to car. For most fixed arms as you add camber its harder to get more caster.
Thread Starter
Racer
Joined: Jan 2017
Posts: 496
Likes: 153
From: San Francisco Bay Area
These are the best choice for both camber / caster.
I have these same upper arms, I run - 3.6 degrees camber and 6 degrees caster (track days). This was not possible with any other upper arms.
Because the global west arms are fixed lengths the amount of camber you get varies car to car. For most fixed arms as you add camber its harder to get more caster.
I have these same upper arms, I run - 3.6 degrees camber and 6 degrees caster (track days). This was not possible with any other upper arms.
Because the global west arms are fixed lengths the amount of camber you get varies car to car. For most fixed arms as you add camber its harder to get more caster.
Advanced
Joined: Feb 2017
Posts: 75
Likes: 16
From: Holtsville NY
These are the best choice for both camber / caster.
I have these same upper arms, I run - 3.6 degrees camber and 6 degrees caster (track days). This was not possible with any other upper arms.
Because the global west arms are fixed lengths the amount of camber you get varies car to car. For most fixed arms as you add camber its harder to get more caster.
I have these same upper arms, I run - 3.6 degrees camber and 6 degrees caster (track days). This was not possible with any other upper arms.
Because the global west arms are fixed lengths the amount of camber you get varies car to car. For most fixed arms as you add camber its harder to get more caster.
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Old Pro Solo Guy
Joined: Dec 2017
Posts: 7,937
Likes: 4,295
From: Marlton NJ
4 degrees of caster should be fine for the street. It is double what the PS cars (2 degrees ) have or 4 times what the MS cars had.
You can definately feel the difference in those settings. Turning effort increases, cornering feedback increases, self-centering increases, it goes straighter down the highway, and it darts less side to side, and is less nervous.
I doubt you could feel the difference if you pushed it to 5 or 6 degrees unless you were racing it, and fine tuning it.
How much camber? Very critical number. More so than caster. Around 0.5 to 1.0 degree neg if street?
Ditto on toe-in. You want very little. Less than factory. Controls tire wear. Close to zero.
You can definately feel the difference in those settings. Turning effort increases, cornering feedback increases, self-centering increases, it goes straighter down the highway, and it darts less side to side, and is less nervous.
I doubt you could feel the difference if you pushed it to 5 or 6 degrees unless you were racing it, and fine tuning it.
How much camber? Very critical number. More so than caster. Around 0.5 to 1.0 degree neg if street?
Ditto on toe-in. You want very little. Less than factory. Controls tire wear. Close to zero.
Race Director
Joined: Mar 2017
Posts: 11,797
Likes: 4,420
From: Virginia
Nice chart, thanks! I see recommendations as high as 7 degrees from some others, including Van Steel. It seems that the limitations of the stock-style arms may have limited some of the recommendations.
Thread Starter
Racer
Joined: Jan 2017
Posts: 496
Likes: 153
From: San Francisco Bay Area
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 592
Race Director
Joined: Mar 2017
Posts: 11,797
Likes: 4,420
From: Virginia
I figure I'll add a bumper of cut garden hose around the arm the next time I think of it.