Modern Spindles

[OLKY55]

This is more a philosophical question than anything, but why haven't any of the spindle manufacturers come up with a spindle using a flipped lower ball-joint? It seems like the car could be lower with a level a-frame and still use the stock-style a-frames. I realize you don't get Corvette geometry, but at least you wouldn't have to modify the frame. It's just something I've been curious about for a while.

[chevynut]

Olky55, I guess I really don't see the advantage. The lower a-arm should theoretically be level from the pivot at the frame through the balljoint center, so if the balljoint was higher the a-arm end would have to be lower, thus raising the car with a given spindle position. I'm not sure why some new cars use this "flipped" balljoint configuration. To lower the car all they really have to do is raise the spindle location, as they have done with dropped spindles. I don't see how a "flipped" balljoint helps them do that. One thing they could do to improve performance is to make a taller spindle, like those available for early Camaros and other cars. I don't think those are on the market for Tri5s.

[OLKY55]

Chevynut,
The way I was looking at it, if the lower a-frame is level, the wheel could be raised by the thickness of the spindle and nut - thus lowering the car by that amount. I'm sure there are other considerations like clearance for steering and such. Us engineers just wonder about these things.

[Rick_L]

I pretty much agree with Cnut here. The ball of the ball joint is what creates the geometry. Whether the ball joint pin points up or down is kind of irrelevant, and the rest is just metal connecting what needs to be connected.

A couple of minor points. Having the ball joint pin point down puts the joint in compression as long as there's weight on the tire. A little bit of belt and suspenders. The other thing is that the dropped spindles were originally meant as a stand alone modification and for the most part still are. Flipping the ball joint would require some other changes.

[rockytopper R.I.P 5-13-2017]

This is more a philosophical question than anything, but why haven't any of the spindle manufacturers come up with a spindle using a flipped lower ball-joint? It seems like the car could be lower with a level a-frame and still use the stock-style a-frames. I realize you don't get Corvette geometry, but at least you wouldn't have to modify the frame. It's just something I've been curious about for a while.

SC&C offers upper adjustable A-arms with a taller howe ball joint and drop springs. They will achieve front corvette suspension geometry on a stock trifive frame. Just an FYI.
Rocky

[chevynut]

SC&C offers upper adjustable A-arms with a taller howe ball joint and drop springs. They will achieve front corvette suspension geometry on a stock trifive frame.
Rocky

I don't think so, if you're referring to a C4 Corvette. The steering axis inclination, anti-dive, and other geometric factors cannot be changed by changing a-arms and balljoints. It looks like the Howe balljoints might be 1/2" or so taller than stock which isn't very significant.

Drop springs will change the angle of the lower a-arms, by raising the end of them so they point downwards toward the center of the frame. That is not the way they're supposed to sit at ride height. The correct way to lower a car 2" or more is dropped spindles. This stuff all has to work as a system.

You can probably get more caster, slightly more camber gain, a change in roll center (by raising the upper balljoint), and that's about it from those parts.

The parts you mention may improve the geometry of the Tri5 suspension, but in no way do they "achieve front corvette suspension geometry". If you think they do, please provide information to prove it. Do you know anyone who has done a thorough analysis of both geometries to compare them?

[chevynut]

SC&C offers upper adjustable A-arms with a taller howe ball joint and drop springs. They will achieve front corvette suspension geometry on a stock trifive frame.
Rocky

I don't think so, if you're referring to a C4 Corvette. The steering axis inclination, anti-dive, and other geometric factors cannot be changed by changing a-arms and balljoints. It looks like the Howe balljoints might be 1/2" or so taller than stock which isn't very significant.

Drop springs will change the angle of the lower a-arms, by raising the end of them so they point downwards toward the center of the frame. That is not the way they're supposed to sit at ride height. The correct way to lower a car 2" or more is dropped spindles. This stuff all has to work as a system.

You can probably get more caster, slightly more camber gain, a change in roll center (by raising the upper balljoint), and that's about it from those parts.

The parts you mention may improve the geometry of the Tri5 suspension, but in no way do they "achieve front corvette suspension geometry". If you think they do, please provide information to prove it. Do you know anyone who has done a thorough analysis of both geometries to compare them?

[rockytopper R.I.P 5-13-2017]

I am no expert on this subject by any means. You will need to talk to Marcus at SC&C. He wrote the book on this subject 610-381-6100. But I run this setup on my 65 cutlass and the only difference is they use a taller ball joint on the lower A-arm also on the A-bodys. Which is basically giving you a taller spindle without spending as much $$$. My front in alignment specs are -1* camber,+5* caster and 0 toe. For serious road racing or autocross they go as much as -2.7 degrees of camber on this setup. Just a quick look see link the C6 alignment is the same more or less. I'm sure C4 & C5 are similar. According to Marcus a longer lower ball joint is not necessary because the trifive stock geometry is better than a 60's a-body which has bad bump steer issues. I have purchased this for my nomad and Marcus has stated the front alignment will be about the same as my cutlass has which matches a modern vet or very close.
Rocky
http://forums.corvetteforum.com/c6-tech-performance/3107257-base-c6-wheel-alignment-specs-etc.html

[chevynut]

A tri5 spindle looks to be abut 11 1/4" from balljoint to balljoint, based on my crude measurements. A late C4 Corvette spindle is about 13 1/2" tall. I realize that's only part of of the geometry, and the location of the inboard a-arm mounts also affect it. The C4 Corvette has 6 degrees of caster, 8.7 degrees SAI, and about 11-12 degrees of anti-dive built into the upper a-arms angles. I know a lot of anti-dive is not always desirable, but I would think it would be on a car that's driven hard.

I sure would like to see someone compare the C4 suspension to the one Rocky mentioned using some suspension modeling software.

[chevynut]

I am no expert on this subject by any means. You will need to talk to Marcus at SC&C. He wrote the book on this subject 610-381-6100. But I run this setup on my 65 cutlass and the only difference is they use a taller ball joint on the lower A-arm also on the A-bodys. Which is basically giving you a taller spindle without spending as much $$$. My front in alignment specs are -1* camber,+5* caster and 0 toe. For serious road racing or autocross they go as much as -2.7 degrees of camber on this setup. Just a quick look see link the C6 alignment is the same more or less. I'm sure C4 & C5 are similar. According to Marcus a longer lower ball joint is not necessary because the trifive stock geometry is better than a 60's a-body which has bad bump steer issues. I have purchased this for my nomad and Marcus has stated the front alignment will be about the same as my cutlass has which matches a modern vet or very close.
Rocky
http://forums.corvetteforum.com/c6-tech-performance/3107257-base-c6-wheel-alignment-specs-etc.html

Rocky, "alignment" is not the same as "geometry". You can get the same alignment with just about any suspension. Alignment refers to the angles of the tires at rest, and while turning at ride height, things like caster, camber, and toe. Geometry refers to the static and dynamic position of the suspension, which is determined by the angles, lengths, and positions of the suspension components. Geometry determines things like anti-dive, scrub radius, roll centers, ackerman, etc.