[Prev][Next][Index][Thread]

Re: <E30> negative camber

mulh0006@domain.elided wrote
> 
> >     As the last step in setting up my DSP 318i, I had negative camber
> > added to the front wheels.  I was expecting to have the strut mounts
> > slotted and pushed inward.  My reputable alignment mechanic called me and
> > said that he didn't want to slot the mounts as it would completely
> > rearrange the front suspension geometry.  Instead of slotting on E30s, he
> > bends the strut where it attaches to the wheel.  This is essentialy
> > the same as most cars where there are bolts at the bottem of the strut to
> > adjust camber.  By bending, the strut tube stays at the same angle
> > relative to the car, but the wheel-to-strut angle is changed.  My
> > question to the digest is; what is the perfered way of adding negative
> > camber to E30s?  Is my mechanic's procedure used elsewhere?  He
> > mentioned to me that few shops are able to percisly bend struts.

egabc@domain.elided replied
 
> I thought about this for a week and never did like the bending of the strut,
> but could not figure out what I didn't like about it until the other day. If
> you think about the front strut like a gate in a fence with two hinges, you
> realize the hinges must "point at" each other for the gate to be able to
> swing without the hinges binding. Conversely, the strut's pivot points (the
> top strut bearing and the lower ball joint connection the control arm) must
> also be aligned, so that binding doesn't occur when steering left and right.
> 
> While this isn't a perfect analogy, I believe it also true for the front
> suspension "hinge" points to be aligned like the gate's hinges. If you bend
> the strut so that the two pivots points are no longer in alignment, it may
> bind when steering, like the un-aligned gate's hinges. When moving the top 
> of the strut tower (by slotting or camber plates) the strut's alignment of
> pivot points is not disturbed, so it should still steer freely.
> 
> Also, after looking at my E30's front suspension today, there doesn't seem
> to be a good place to bend it. Lastly, how do you guarantee that both sides
> get bent equally, and that the relationship between steering, axle stub and
> brake calipers isn't upset?

  Getting both sides equal isn't difficult becuase the car is on the 
alignment rack when it is done; how, I don't know.  Can someone on the digest 
shed some more light on this subject?  I am concerned that my car might 
not be handeling as well as it would with unbent struts and slotted 
strut mounts.  I want to go back to my mechanic and talk to him about 
what he has done, but he is likely to argue that he has much more experince 
than I (which he does), and that he knows exactly what he is doing.  How 
can I argue with that?  

> BTW, how did you get to -1.5 to start with at the front? Was this just from
> lowering? You're probably already aware that BMW has OEM camber correcting 
> top strut mounts which will give you another +/- .5 deg camber.

  Before the alignment, I had -1.02/left -1.52/right (unweighted); with 
me in the car I had -.96/left -1.93/right.  This is with the car lowered 
~2 in. (2 coils cut on front springs).  I expected the neg. camber to 
increase (more neg.) on the left when I got in the car, but the opposite 
happened; the right side got more negative.  Does anyone know why?  After 
I had the struts bent, I ended up with -2.1 left & right.  I suspect this 
is unweighted, but I could be wrong.

Thank you for the bandwidth.

mulh0006@domain.elided