SPC Adjustable Ball Joint Install How-To
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Joined: Aug 2002
Posts: 48,203
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From: Lewisville, TX
Originally Posted by Clark,Jul 31 2009, 10:49 AM
I haven't run enough on them yet to know that, and I was making the step up to Hoosiers (or whatever good take-off slicks are available) from RA-1's at the same time, so I was just going at first by the seeming consensus of -4 to -4.5 that the full-on racers seem to go with on this forum.
I also made this change while changing cars, so not only do I not have data logging for before and after empirical comparison, but I don't even have a good immediate back-to-back feel, and with the tire change lap times aren't really comparable either.
From there I was going to use tire temps with a pyrometer to see if I had the appropriate camber for the track. Unfortunately I've had to deal with a couple other minor problems first that kept me from getting there yet.
Right now I'm running:
Front max camber w/SPC installed at 45 degrees + lowered @ 3/4":
-4.3 static camber
1/16" to out
7.0 Caster
Rear, no adjusters + lowered @ 3/4":
-3.2 static camber
zero toe
I also made this change while changing cars, so not only do I not have data logging for before and after empirical comparison, but I don't even have a good immediate back-to-back feel, and with the tire change lap times aren't really comparable either.
From there I was going to use tire temps with a pyrometer to see if I had the appropriate camber for the track. Unfortunately I've had to deal with a couple other minor problems first that kept me from getting there yet.
Right now I'm running:
Front max camber w/SPC installed at 45 degrees + lowered @ 3/4":
-4.3 static camber
1/16" to out
7.0 Caster
Rear, no adjusters + lowered @ 3/4":
-3.2 static camber
zero toe
Chassis Setup Recommendations
For optimum performance the Hoosier P-Metric radial tires require about 3 degrees of camber. There will be a trade off in maximum performance to maximize wear. Generally, 1/2 degrees less than optimum will result in the best compromise for wear and speed. Less than 2.5 degrees can result in excessive wear on the shoulder junction.
The Hoosier tires typically offer better performance with spring/shock rates higher than previous brands you may have run.
For optimum performance the Hoosier P-Metric radial tires require about 3 degrees of camber. There will be a trade off in maximum performance to maximize wear. Generally, 1/2 degrees less than optimum will result in the best compromise for wear and speed. Less than 2.5 degrees can result in excessive wear on the shoulder junction.
The Hoosier tires typically offer better performance with spring/shock rates higher than previous brands you may have run.
Joined: Feb 2001
Posts: 1,045
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From: Chicago
FF2Skip,
Well the Hoosier recommendations are surely a good baseline to start with when choosing your alignment. There is no argument there.
I merely started with the experiences of racers and generally knowledgeable & fast (or so they claim
guys on this forum as a baseline, and an aggregation of that reading seemed to say 'up to -4.5 degrees camber up front on race rubber' was useful.
Similar opinions were expressed about rear camber, but there seemed to be less people trying as many things to get more rear camber and living with the max they could get with the equipment / lowering they had. Also I'm sure that my car does not meet the 'higher spring & shock rate' caveat in the Hoosier recommendation (KWv3..... coil-overs)
As I suggested earlier, the next step is to use a proper probe pyrometer to measure the temperature spread across the width of the wheel to see if I'm optimally aligned for my usage and adjust from there. I just haven't done that yet as other things have been more pressing my last several outings.
I'm less concerned about optimal wear as I'm just doing track days and not caring for a tire over a long race stint. Since I'm buying take-offs, they're already dirt cheap so I'm happy to chew em up and spit them out.
This last set of Hoosier R6's was both my first time on Hoosiers and they were take-offs, so it's no guarantee it'll always be that way, but even with the above alignment, when I finally corded a couple of the tires, it was on the outside of the tire (with the above alignment). The tire pressures were within range, and as I said I'm not sure about temps, so I'll have more investigation to do.
Well the Hoosier recommendations are surely a good baseline to start with when choosing your alignment. There is no argument there.
I merely started with the experiences of racers and generally knowledgeable & fast (or so they claim
guys on this forum as a baseline, and an aggregation of that reading seemed to say 'up to -4.5 degrees camber up front on race rubber' was useful. Similar opinions were expressed about rear camber, but there seemed to be less people trying as many things to get more rear camber and living with the max they could get with the equipment / lowering they had. Also I'm sure that my car does not meet the 'higher spring & shock rate' caveat in the Hoosier recommendation (KWv3..... coil-overs)
As I suggested earlier, the next step is to use a proper probe pyrometer to measure the temperature spread across the width of the wheel to see if I'm optimally aligned for my usage and adjust from there. I just haven't done that yet as other things have been more pressing my last several outings.
I'm less concerned about optimal wear as I'm just doing track days and not caring for a tire over a long race stint. Since I'm buying take-offs, they're already dirt cheap so I'm happy to chew em up and spit them out.
This last set of Hoosier R6's was both my first time on Hoosiers and they were take-offs, so it's no guarantee it'll always be that way, but even with the above alignment, when I finally corded a couple of the tires, it was on the outside of the tire (with the above alignment). The tire pressures were within range, and as I said I'm not sure about temps, so I'll have more investigation to do.
Thread Starter
Former Moderator
Joined: Jul 2005
Posts: 4,634
Likes: 28
From: West Virginia
I've been running my SPC front ball joints with -3 degrees of front camber for 2 1/2 years now with no problems. I do not run the top plate at 90 degrees and haven't had any slip. I run the ball joints at their max negative camber setting (top of wheel slid in full).
My right front upper A-arm began to pull itself off the frame and the car holds the street legal S2000 track record at Summit main. The SPC ball joints are taking some serious abuse and holding up.
I think -3 degrees is about right for me. My tire temps are running pretty even and wear is good too requiring 1 flip of the tires on the rim to achieve even wear throughout the life of RA1s and NT01s. Any more camber will cut down the contact patch during straight line braking.
Rob
My right front upper A-arm began to pull itself off the frame and the car holds the street legal S2000 track record at Summit main. The SPC ball joints are taking some serious abuse and holding up.
I think -3 degrees is about right for me. My tire temps are running pretty even and wear is good too requiring 1 flip of the tires on the rim to achieve even wear throughout the life of RA1s and NT01s. Any more camber will cut down the contact patch during straight line braking.
Rob
Registered User
Joined: Aug 2002
Posts: 48,203
Likes: 10
From: Lewisville, TX
Originally Posted by CKit,Aug 3 2009, 09:21 PM
Does anyone have their OEM parts for the front A-arm ball joints? I'm thinking of removing my SPC joints and not sure if you can purchase those parts separately...
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Joined: Aug 2004
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I'm in talks to get a set of used upper and lower A-Arms from a part-out car. It'll be easier to swap out the arms rather than trying to reassemble the OEM joint (durn flat rounded SPC nut).
The lower arms might have fresher alignment adjusters. We've been having to realign pretty much monthly. I have a theory that even if the plate in the SPC doesn't slide, there can be rotation of the offset joint that screws with the alignment and geometry.
We're running 285s up front on 18x11 CCWs and only get one full turn before we're rubbing the shock bodies... spinning often puts the wheel into the A-Arm and can pull on the ball joint. With the SPC joint being offset, that force can swivel the offset and mess with the alignment.
Well, that's my theory. They haven't held up well to aggressive autocrossing and I think the design of the joint isn't a durable solution for that kind of grip and abrupt transitioning.
So I'm going back to stock control arms and doing a J's lower offset joint. I just need a few more degrees of negative camber than stock and don't need the hassle of variable toe.
The lower arms might have fresher alignment adjusters. We've been having to realign pretty much monthly. I have a theory that even if the plate in the SPC doesn't slide, there can be rotation of the offset joint that screws with the alignment and geometry.
We're running 285s up front on 18x11 CCWs and only get one full turn before we're rubbing the shock bodies... spinning often puts the wheel into the A-Arm and can pull on the ball joint. With the SPC joint being offset, that force can swivel the offset and mess with the alignment.
Well, that's my theory. They haven't held up well to aggressive autocrossing and I think the design of the joint isn't a durable solution for that kind of grip and abrupt transitioning.
So I'm going back to stock control arms and doing a J's lower offset joint. I just need a few more degrees of negative camber than stock and don't need the hassle of variable toe.