School me on drop spindles...
This is info from another forum where a member there used my suspension geometry, with drop spindles, to do an analysis using a suspension program to figure out the advantages/disadvantages to running drop spindles. As you can see from the data, the bump steer was increased using drop spindles, as was the roll center. The bump steer change is relatively minor, but its still in the wrong direction. And the change in roll center was significant.
This is info from another forum where a member there used my suspension geometry, with drop spindles, to do an analysis using a suspension program to figure out the advantages/disadvantages to running drop spindles. As you can see from the data, the bump steer was increased using drop spindles, as was the roll center. The bump steer change is relatively minor, but its still in the wrong direction. And the change in roll center was significant.
Okay, I think I've got enough of this down to finally share some results. Please keep in mind I'm still learning my way around this, so I won't say these a guaranted results, but I think I've got a jump on it for the moment.
First up, a typical stock suspension mopar cranked down quite a bit. I took these from my car which is running a 26" tall front tire on a 15x8 rim, 4.5" back space. Alignment is 3.22 caster, -.5 camber, 0 toe, RC height is 5.53.
Here is a corner shot with 3" of shock travel. That is a significant amount of movement. Note teh caster, camber, and toe changes. RC height changed only .03" up.
Now here is a look at bump steer. This is only one side, but since the set up is symetrical, both sides are the same in this example. In 2" of travel, 1" jounce to 1" rebound, bump changes .2", or slightly less than a quarter inch.
Next up are using 72b&b measurements provided earlier in the tread. Since the plots for this are three dimesional, I did make some assumptions about fore/aft locations and centerline to outboard measurements using the numbers from my car. These should all be very close in cars using stock style components. What I wanted to capture was the change in control arm vertical locations.
First up is the static measurements. Tried to get caster, camber, and toe as close to the previous example as possible with 3.48 caster, -.5 camber and 0 toe. RC height is at 8.25".
Next up is the corner simulation. Similar types of movements in most locations. Toe changes are greater.
Here is a bump steer snap shot. I didn't get the scale the same, so it appears really bad, but you need to look more closely at the actual points in the similar range. Looking at +1 to -1 in range, we have roughly .15" per side for a total of almost .3" of bump through the range, or about .05" more than movement than a lowered stock set up.
