[s-cars] Alignment hacking

[Kevin Day]

Okay... I guess I can figure out how much to move the strut to push the 
camber out by 0.5 degrees.  I just need to measure the length of the strut.  
But how I can calculate how much this adjustment will affect toe?

Camber adjustment calculation:

Let S = length of strut from ball joint to camber plate
Let D1 = distance mount is inboard from 0 deg.  at -1.2 deg. camber
Let D2 = distance mount is inboard from 0 deg.  at -0.7 deg. camber

D1 = sqrt( s^2 - ( s * cos(1.2) )^2 )
D2 = sqrt( s^2 - ( s * cos(0.7) )^2 )

(This is assuming the camber plate slides parallel to the ground, which I
don't think it does, quite, but close enough I guess.)

So D1 - D2 is amount I should move the strut plate outboard if I am at
-1.2 and I want to be at -0.7. 

If I assume the strut length is 18", this says move the mount outward by
0.157" on each side.  I guess that's in the ballpark, eh?

What are the odds I can do this with a ruler and not make the alignment
even worse?  Hmm... 

It'd be easiest to do this with the wheel lifted off the ground, right?

-Kevin


On Mon, Nov 07, 2005 at 09:35:43PM -0500, Tom Mullane wrote:
> Kevin,
> I suppose you *could* do that, but when you alter camber, you alter toe.  Push
> the tops of the struts out for more camber, and you toe the car in...which
> maybe isn't a terrible thing, since that will help wear the outside edge of the
> tire too.  
> Tom 
>  
> Date: Mon, 7 Nov 2005 20:29:19 -0500
> From: Kevin Day <_k_d_a_y_@_u_l_t_r_a_m_e_t_a_._o_r_g>
> Subject: [s-cars] Alignment hacking
> To: _s_-_c_a_r_-_l_i_s_t_@_a_u_d_i_f_a_n_s_._c_o_m
> Message-ID: <_2_0_0_5_1_1_0_8_0_1_2_9_1_9_._G_B_1_4_3_1_9_@_u_l_t_r_a_m_e_t_a_._o_r_g>
> Content-Type: text/plain; charset=us-ascii
> 
> This may be a silly question, but bear with me.
> 
> I had my car aligned back in May after installing 1992 S4 springs
> instead of the stock 1994 springs.  The printout I have shows -1.2
> camber measured on both RF and LF after the alignment.  The inside
> of the front tires is wearing quite a bit faster than the outside.
> (Not a surprise to some of you I'm sure.)  Since I have new tires
> on the way, I want to fix the wear issue.
> 
> So the question is: given that I essentially need to add a fixed amount
> of positive camber to each side, can I possibly do this in my driveway?
> 
> Thanks (even if your answer is "don't be a dumbass, go get another
> alignment")
> -Kevin
>