Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle? - Page 4
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2004-2007 Cadillac CTS-V Performance Mods Discussion, Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle? in Cadillac CTS-V Series Forum - 2004 - 2007; good info...
  1. #46
    liqidvenom is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    good info

  2. #47
    TimmyC is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    STS spindles are aluminum. Has anyone looked at those?

    http://www.ebay.com/itm/07-CADILLAC-...-/160944037698

  3. #48
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Quote Originally Posted by TimmyC View Post
    STS spindles are aluminum. Has anyone looked at those?

    http://www.ebay.com/itm/07-CADILLAC-...-/160944037698
    I can immediately see that the top of the spindle will not be compatible with the CTS-V1 upper control arms. I just contacted the seller, asking them to weigh the piece. If there's a significant weight loss possible, I'll let you all know.

  4. #49
    TimmyC is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    I can't see the top of the CTS spindle. What is not compatible?

  5. #50
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Quote Originally Posted by TimmyC View Post
    I can't see the top of the CTS spindle. What is not compatible?
    The STS spindle requires an upper control arm that has a threaded ball joint. The 04-07 CTS-V upper control arm has a threadless ball joint that relies on the upper branch of the spindle to pinch closed, capturing a machined rib in the ball joint. If you were to simply swap in the STS part, you would not be able to drive the car. because you would not be able to secure the upper control arm to the spindle.

    Unfortunately, I've checked everywhere and cannot find threaded ball joints that fit the 04-07 upper control arm. If I could, it would make things much easier. Given that, the next step is to buy a couple of 09-13 upper control arms, test fit them, and if they fit, then see if they're compatible with this STS spindle. They might not be. There's a possibility that the increased caster angle, caused by the 09-13 control arm, will cause contact between the bottom corner of the spindle and the lower control arm. The ball joint in the 04-07 CTS-V lower control arm has a limited range of articulation, and the 09-13 upper control arm is going to be pushing it.

    All of this is a moot point if the STS spindle isn't appreciably lighter than the CTS-V spindle.

  6. #51
    TimmyC is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Would sts control arms work

  7. #52
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Quote Originally Posted by TimmyC View Post
    Would sts control arms work
    Using the Mark 0 eyeball, I'd say no. It looks too pushed out--you'll probably scrub the inside rim of your wheels on the spindle. And even if it works, you'd pay a huge price in terms of camber gain during cornering. But you just helped me find a potentially compatible upper ball joint. The K500065. Of course, I'll need to buy an Arbor press to start experimenting. Harbor Freight sells these small (30" tall) 6-ton presses for $70. It's on my list now.

    http://www.harborfreight.com/6-ton-a...ress-1666.html

  8. #53
    TimmyC is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Hmm, that's all I have to add to the party.

  9. #54
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Quote Originally Posted by TimmyC View Post
    Hmm, that's all I have to add to the party.
    Hey, I appreciate it. Your input was invaluable!

  10. #55
    TimmyC is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Quote Originally Posted by FuzzyLogic View Post
    Hey, I appreciate it. Your input was invaluable!
    Thanks. I guess it was a little addition by subtraction. We know one more part that doesn't work.

    It seems that milling some unneeded material out of the CTS-V knuckle would be the easiest way to reduce the weight.

  11. #56
    ctsv247 is offline Cadillac Owners Enthusiast
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    So creative steel, ready to pull another one off for us? Looks like a matched set of upper and lower arms that would allow us to bolt on a v2 spindle would be a winner. I would rather buy a set of fully assembled arms than go to the hassle of installing bushings and balljoints in my old ones....

  12. #57
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    Quote Originally Posted by TimmyC View Post
    Thanks. I guess it was a little addition by subtraction. We know one more part that doesn't work.

    It seems that milling some unneeded material out of the CTS-V knuckle would be the easiest way to reduce the weight.
    Given the fact that the CTS-V2 spindle is aluminum, but much larger than the V1's steel spindle, do you think that Cadillac made a mistake casting the STS spindles in aluminum from nearly the same mold as the CTS-V? You've gotta wonder if the aluminum STS spindles are stiff enough to handle the cornering loads that we would throw at it.

  13. #58
    ctsv247 is offline Cadillac Owners Enthusiast
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    If they're using those on the sts-v you would have to think they'd work alright for us. Maybe they had to use aluminum because they were getting close to a weight threshold of some sort.

  14. #59
    TimmyC is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    The STS spindles don't break so I'd say the mistake was using cast iron in the CTS spindles. I never knew they were iron. I assumed the whole front suspension was the same as the STS with the exception of the caliper location.

  15. #60
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Unsprung Weight Reduction: 09-13 Forged Aluminum Knuckle?

    I just bought the 2007 STS-V aluminum spindles.




    I'll publish part numbers and additional information if/when I engineer a solution. I'm confident enough to put a couple hundred more dollars on the line. However, I don't yet know whether it'll require a) replacing the ball joints on the CTS-V1 UCAs with threaded ones, b) replacing the CTS-V1 UCAs with STS-V UCAs, or c) replacing the CTS-V1 UCAs with CTS-V2 UCAs.

    I don't want to get you all excited, but the CTS-V iron spindle weighs 13.1 lbs, and the STS-V spindle weighs 8.7 lbs, for a 4.4 lb weight reduction per corner. If you had to buy everything new, the STS-V spindle costs $180 and the UCA assembly costs $250. Used prices are roughly 1/2 that. Compare that with the two-piece 355mm (not the 370mm) RacingBrake rotor, which weighs 21.5 lbs versus the OEM 26.0 lb rotor and costs about $400 each. Combine the two and you've lost 8.9 lbs of unsprung weight. The CTS-V1 caliper weighs 11.6 lbs (including Ferodo HP1000 pads) whereas the CTS-V2 caliper weighs 13.0 lbs (including ET800 pads). OEM and SKF X-Tracker hubs weigh exactly the same, or at least within the 0.1 lb accuracy of my scale. Therefore, net unsprung weight reduction on each corner should be 7.5 lbs.

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