Rear Toe Settings vs. half-shaft angle

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Nov 26, 2002 | 12:26 PM

75 BBC Stingray

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From: Marlborough MA

Rear Toe Settings vs. half-shaft angle

Could use some help here. I've downloaded the VIP and Six-Link articles from Corvettefaq. I've not been able to grasp the statements that for better toe settings, the axle shafts (VIP) or upper/lower struts (Six-Link) need to be statically set at a certain angle. Since the toe can be set statically independently of the strut/axle angles, what is the interaction?
To lock in the axle shafts at a particular angle (inner U-joint 1/2" higher than outer - VIP) also locks in the rear ride height unless you move the differential higher/lower in relation to the frame, which would seem to be a PITA.
For the six-link they say that the adjustment of ride height (static angle of struts) will setup for neutral/oversteer/understeer while cornering.

Can someone explain the interaction?

Nov 26, 2002 | 06:51 PM

75 BBC Stingray

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From: Marlborough MA

Re: Rear Toe Settings vs. half-shaft angle (75 BBC Stingray)

ttt

Nov 26, 2002 | 09:05 PM

Colin

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From: Phoenix AZ

Re: Rear Toe Settings vs. half-shaft angle (75 BBC Stingray)

I'm not fully understand your question but something I noticed is I'm not sure you mean toe. Toe is the tire's inward or outward tilt on the front or back of it, not top or bottom. So a top view of a car with toe-in would look like / \ and toe-out would look like \ / while zero toe would be l l.
I think the term you want is camber which is the tilt of the tire leaning inward or outward on the top or bottom.
Or I might just be completly misunderstanding your question. I apologize if that's the case.

Colin

Nov 27, 2002 | 08:08 AM

vettfixr

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From: Sewell NJ

Re: Rear Toe Settings vs. half-shaft angle (75 BBC Stingray)

There are only two adjustments to the rear that can be made. The first is toe in/toe out. This is changed by removing or adding shims to the front of the trailing and changes the relationship of the tire to a straight ahead position. The other adjustment is for camber. This is the tilting in or out of the wheel at the top. Changing this is accomplished by adjusting the eccentric on the strut rod of a stock setup or adjusting the length of the strut on the VBP adjustable strut rod. This moves the bottom of the tire in or out thereby causing the top of the tire to move also but in the opposite direction (e.g.moving tire out at bottom causes top to move in). Both of these adjustments are affected by ride hight. In the case of an adjustable height rear spring (one with long adjusting bolts) the ride height should be set first to get the proper angle on the halfshafts or to adjust the body height to account for large tires, etc. once this setting is made you can adjust the other two. I'm not sure of the difference with the product you're referring to vs. stock but if this doesn't answer your question I would contact the manufacturer and get it from the horses mouth. Hope this helps.

[Modified by vettfixr, 8:10 AM 11/27/2002]

Nov 27, 2002 | 12:22 PM

75 BBC Stingray

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From: Marlborough MA

Re: Rear Toe Settings vs. half-shaft angle (Colin)

Sorry for the lack of clarity, but I am confused about the toe (toe in/toe out), not the camber (that I can understand pretty well). Stated in the two mentioned articles is that the toe changes as the suspension moves up or down. It is recommended that the suspension location in the rebound/jounce path be set to a particular height, then the toe/camber statically set. My question is if the toe can be set independently of the ride height (in other words you could statically set a particular toe in for the suspension at any point on the jounce/rebound curve) what do you care where the suspension is as long as you have the toe you want when the car is at rest.

Hope I was a bit clearer, altough it is a tough idea to convey in just a post... :confused: :confused:

Nov 27, 2002 | 01:42 PM

vettfixr

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From: Sewell NJ

Re: Rear Toe Settings vs. half-shaft angle (75 BBC Stingray)

I think you understand what they are saying. All they are saying is that the toe will change when the rear of the car bounces up and down because the axles will force the wheels in and out. Set your ride height and then set your toe and you should be ok.

Nov 29, 2002 | 07:51 PM

75 BBC Stingray

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From: Marlborough MA

Re: Rear Toe Settings vs. half-shaft angle (vettfixr)

Thanks for those who responded, but I'm still looking for a little more info...
I've thought about this alot over the last week...
The recommendations in the VIP article for the axle shaft angle (inner U-joint 1/2" higher than outer U-joint) effectively sets the ride height. Although I know you could do such mods as moving the differential higher in the frame if you so chose to alter the ride height as well. So if this particular ride height is recommended, then there must be an advantage to this. The only thing that I could think of is that this ride height sets the jounce/rebound range on a particularly good section of the toe change graph.
Something similar would be true for the six-link suspension article.
I see a fair number of people have read this thread, so I'm curious if anyone would like to comment on my thoughts. I'm more curious on the theories invovled.