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My alignment guy said it really has to do with how much you pull the shaft side to side when the car is stationary. He told me it should move about an inch or so. Again, correct me if I'm wrong.
Originally Posted by TrackStar,Mar 12 2007, 01:32 PM
disclaimer* I'm not engineer, so feel free to correct me if I'm wrong*
Technically speaking, I guess I am an engineer, but that doesn't mean that I know everything and/or don't make mistakes. A tech like Bill (et. al.) with lots of experience is often a better source of information than the typical engineering type.
My alignment guy said it really has to do with how much you pull the shaft side to side when the car is stationary. He told me it should move about an inch or so. Again, correct me if I'm wrong.
The S2000's axle has 2 CV's.
Inboard, the bucket & spider & roller type and outboard, the homokinetic joint, also known as RZEPPA CV JOINTS.
We have all seen the picture negcamber posted of the bucket.
This is a homokinetic / rzeppa type:
(picture found on Wikipedia)
The one used outboard on the S2000 is simular to this one but not exactly the same.
The axle is fixed into that CV joint, the same way the output shaft is fixed in the diff, with a circlip.
The axle will not move sideways.
This type of CV does not allow lateral movement.
The bucket type does and is needed.
negcamber Posted on Mar 12 2007, 09:51 PM
BTW...just my theory...but I think the reason lowering the car seems to led to the cv vibration more quickly is because the spider moves just a bit inboard which allows the roller bearings to trammel back and forth from the good bearing surface and the old wear surface.
For the sake of discussion, let's assume that the design of the outer CV housing is strongest at the end where if closes to the spline and places the least amount of off center force on the spline (aka wheel bearing). Accordingly, that's close to where the Honda engineers located the spider bearings to contact the interior slots.
Also for the sake of discussion, let's say that the length of the axel from the companion flange to the spider mount is 3.65' (112 cm). When the car is at normal ride height the companion flange is either very slightly above or even with the spider inside the outer CV housing forming the length of a straight line.
So, we drop the car 1.5" or 3.81 cm. We now have a triangle. The base of the triangle is 3.81 cm and the height of the triangle is 112 cm to reach the designed engagement point for the spider. However, the shaft is only 112 cm long. So, to make the shaft that is now the hypotenuse of the triangle reach the same point 112 cm from the height we need to add distance. That distance is really only 1-2 cm. However, if you want to run the spider out to the strongest point to the outer frame of the housing, you need to add 3-5 additional cm.
On the track and when you drop the clutch, it will add strength and lower the failure rate in my humble opinion.
Here's a rough diagram.
I totally agree, regarding the AP1, but how does the AP2 differ, and are the spacers beneficial on an AP2.
My thinking has always been that if the spacers are indeed needed, then the thickness of the spacer needs to be determined based on the drop. A spacer that is correct for a 1" drop will not be correct for a 2" drop. Also, what happens when the suspension goes into droop? Isn't the spacer going to be a problem when the suspension is back at (or above) the position of stock ride height? Seems that you'd want the thinnest spacers that would get the job done.
I follow you, however. The inner drive bucket doesn't offer any resistance if you move it outwards towards the alxe shaft.
In your diagram, moving the axle outward with spacers will bring the shaft and outer cv outward, returning the outer cv to it's original position. That makes sense.
HOWEVER.....if you put a spacer inbetween the drive bucket and the dif, you won't move the axle! All you will change is the drive bucket's position on the axle. The only thing that would force the axle outwards would be the AIR setting. When you rebuild an axle, you have to bleed off the air in the boot to set the installed length.
Originally Posted by RED MX5,Mar 12 2007, 06:29 PM
A spacer that is correct for a 1" drop will not be correct for a 2" drop. Also, what happens when the suspension goes into droop? Isn't the spacer going to be a problem when the suspension is back at (or above) the position of stock ride height? Seems that you'd want the thinnest spacers that would get the job done.
Would be great to have some real world data to see what thickness spacer works best with different ride heights. And I would assume ride height would need to be measured from the ground to a point on axle since in reality different aspect ratio tires can even effect that axle angle.
Looks like the spacer thickness can be calculated by having the length of the axle and the height to the axle at both the hub and the diff flange.
[QUOTE=negcamber,Mar 13 2007, 10:59 AM] Would be great to have some real world data to see what thickness spacer works best with different ride heights.
03-12-2007, 01:01 PM
