Another rear sway bar thread
- Thread starter IrvJr
- Start date
IrvJr
Well-Known Member
- Joined
- May 28, 2001
Im trying to gather as much info here and looking elsewhere as well. Calling Speedway and SC&C. I met a cool lady named Jean who runs Evolution Driving school and is gonna get me a few guys numbers to call and ask them some details too. Im not doing anything til I feel comfortable with the choices.
And Charlie's post is why im afraid of replacing my control arms.
And Charlie's post is why im afraid of replacing my control arms.
I thought there was more to those situations than just that. I'm gonna have to reread them. But a few out of hundreds , thousands sold have had some defects? Shiet happens. There's always bound to be some type of failure or defect rate esp in highperformance racing driving whatnot. But it seems a fairly small percentage. Most race application products are for off road only But people push the limits of things on the street. As for the issue with warranty and that , who knows There's always 3 sides of a story. I only can tell of my actual experience with said product and vendor.
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Do a search on this board or post in the general topic for people who have used the spc arms and get their opinions as well. I know will (bent6 ) and jevans I believe are running them also. Pm them. And any more info you may find out from your research please come back and share.
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The arms are basically levers and while the pivot point is on the frame at the top it's got a lot of weight pushing the knuckle up and inwards. While the lower arm and spring hold the chassis up what most don't think about is the upper arm and ball joint are actually holding all that weight so all the stress is on them. The lower ball joint is being pulled on so it can be pulled out if it fails but the upper is under compression and the upper arm is under compression. If you remember your high school physics the strongest structure is tubular VS a solid structure. The arm section of the adjustable arms are a solid piece but where that section attaches to the shaft is necked down and there's the weakest point. The stock arms are stamped steel and the weakest point on them is the angle right behind the ball joint towards the frame. Same issue as the adjustable arms. The necked down section is where they bend.
If they had been made with a tubular part and a screw (bolt if you wish) that moved in and out of the tubular section the arms wouldn't fail as easily, but with the adjuster section being a nut (tubular) and the arm section being solid you end up with the most stress on the section where arm meets the cross shaft. Did that help or make it clear as mud?
scot w.
GNSperformance.com
- Joined
- Feb 19, 2005
I have several sets sitting here that customers swapped out, One set due to the adjusters seizing up for the 3rd time after being replaced twice before and the second set the plate was bent on one upper... We just tossed them about 2 weeks ago...
The "Adjustable" & "No shims" theory sounds cool but it's no good when the adjusters seize up, Plus another down side is adding Neg camber for when you want to autocross, how does one know when/where to stop for adding negative camber? With the DSE track shim kit in my car it's as simple as loosening the bolts and sliding in the correct size shim, tighten bolts down and your ready to go! When I want to drive home or on the street again I simply loosen the bolts and pull out that "One" shim and it's all back to normal street specs... I would hate to see how involved it would be to adjust those uppers to accomplish that..
Did you get pics of the Scott? That would help others to understand the weak area of the design.
scot w.
GNSperformance.com
- Joined
- Feb 19, 2005
No I did not... But both customers have done nothing but praise how well the car drives/handles now....
Unfortunately yes. They've never changed the design to prevent the issue from happening.
So in your opinion Charlie , If they had the threaded tube welded to the ballpoint plate and the mount at the control arm and had A stud with a nut welded on it so you could adjust it, it would be structurally more sound. Ok i follow u on that. I'm wondering if people adjusting the arms incorrectly has anything to do with the failures seen though. You are not supposed to have more than an inch of thread past the jam nut showing. Wonder if this is coming into play? Joel
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The failures aren't happening where the threaded section is, it's happening where the solid sections are. Like I said, it's a copy of a dirt track front arm but those cars weigh between 2100 and 2800 LBS as a rule, and with the engine set back the nose is much lighter. Most of the weight in on the nose of these cars so if you pull the tires off the ground then you'll end up with all that weight hitting really hard. Think about those "strong men" that can bend steel bars. Now if you gave them a steel tube I'd bet it would be straight instead of bent.
83hurstguy
Member
- Joined
- Sep 18, 2005
I've had my SPC pro-lite uppers with Howe tall ball joints on my 3780 lb G-body for 4 years now. Been aligned twice. No galling, no bending, happy as heck with them.
Have yet to see any proof of "multiple SPC failures" other than several members on this forum who talk about it repeatedly but never produce pictures, links or direct references. You would think if they were really that dangerous, in a world where everyone has a camera phone and internet access, pictures of these failures would be everywhere. A UCA failure is pretty catastrophic... you're going to have some significant damage and pissed off customers. There was a failure on pro-touring at the end of last year, the guy had a 1st gen Camaro with Guldstrand mod and the upper arm was installed backwards as well. All the arms to contact the frame... induced bending loads and eventually failed. It was ugly, no doubt... but definitely an installer issue.
Ball joints pretty much always end up installed in plates. Look at how the new G-body Ridetech arms are... plates with bolted in ball joints, welded to a tube. It's obvious that the SPC parts aren't built to be the brick sh*thouse of control arms, but they aren't junk either. Internet postulation of "these look weaker" is not evidence. Any time you mod a car, you mess with the factory engineering... suspension geometry, driveline angles, frame clearance, etc... if you don't look at it with a critical mindset, check everything, and validate safety, the installer can make plenty of errors that cause parts to fail.
Have yet to see any proof of "multiple SPC failures" other than several members on this forum who talk about it repeatedly but never produce pictures, links or direct references. You would think if they were really that dangerous, in a world where everyone has a camera phone and internet access, pictures of these failures would be everywhere. A UCA failure is pretty catastrophic... you're going to have some significant damage and pissed off customers. There was a failure on pro-touring at the end of last year, the guy had a 1st gen Camaro with Guldstrand mod and the upper arm was installed backwards as well. All the arms to contact the frame... induced bending loads and eventually failed. It was ugly, no doubt... but definitely an installer issue.
Ball joints pretty much always end up installed in plates. Look at how the new G-body Ridetech arms are... plates with bolted in ball joints, welded to a tube. It's obvious that the SPC parts aren't built to be the brick sh*thouse of control arms, but they aren't junk either. Internet postulation of "these look weaker" is not evidence. Any time you mod a car, you mess with the factory engineering... suspension geometry, driveline angles, frame clearance, etc... if you don't look at it with a critical mindset, check everything, and validate safety, the installer can make plenty of errors that cause parts to fail.
