Drop spindle questions

[ps2375]

Right now my 69' is at stock ride height. I've added a set of caster shims and added some negative camber and set the toe. It drives and handles pretty well. I've got some 2 1/2" drop spindles arriving soon and am wondering if I need to add another set of caster shims along with the longer bolts. And is there any downside to lowering the front with drop spindles, I know I'll maintain stock suspension travel and shock length(good).
It'll definitely look better, as I have quite a bit of fender gap, I just don't want to hurt the handling.

[Chip Birks]

The only downside I can think of is that your track will widen. I have a 3 inch narrowed beam going in currently to compensate for a set of disks and a set of lowered spindles.

[ps2375]

Why would it widen my track? And I already have Ghia disks on the front.

[Steve Arndt]

It widens the track because to drop the spindle stub the material is made thicker, it is just geometry of how it all fits. Early Jateck welded spindles added a full half inch per side. Cast CB style aftermarket add less offset but still push it out.

[Ol'fogasaurus]

For what it is worth: just remember, as you drop the front of the car, assuming that is all you are doing, the rear stays the same height. This changes the caster in this case e.g., alignment. There does become a point of diminishing returns were making big changes in things get a bit iffy.

http://www.s2ki.com/s2000/topic/60381-h ... y-experts/

This is on "scrub radius" which dropped spindles can affect (see Steve's post above) and probably should be taken into consideration especially because you are not planning on use just on the street; e.g., frontend alignment.

[risk]

I think you will be fine with one set of caster shims..

I have two sets of caster shims in my car, 67 bug with 4" narrowed adjustable beam and 2.5" drop spindles. My car has a pretty aggressive "rake" to the stance. The car handles good and runs straight especially at high speeds. But, the extra caster (I assume) makes it a bit hard to steer at lower speeds. I thought about pulling one shim and seeing if it makes a difference.

[Marc]

I think you will be fine with one set of caster shims.. spindles won't change the caster (if you lower the rear the same amount, that is). Lowering with the adjusters in the beam are what take caster away...

Same result either way. The caster is determined by the angle of the beam relative to the ground; ANYTHING which changes that will affect caster, whether it be adjusters/cut-n-turn, drop spindles, even smaller front tires...or any change which raises the rear. The big difference between altering ride height with the springs and using drop spindles is that the latter maintains stock geometry of the control arms and steering linkage, so it won't induce bump-steer problems.

The pan in my driver `69 sits just about level (lowered ~3" front & rear) and theoretically should not need caster shims, but I still run a set (¼" ones) to add a little caster for better tracking/stability at highway speeds. Caster shims have been around for 60 years, back when VWs were new to the USA and people were accustomed to understeering/plowing Broderick Crawford Buick "handling", if a customer persisted in complaining about how their Bug drove the dealer would throw on a set to see if that would make them happy. The trade-off? A slight increase in steering effort, noticeable at low speeds (camber causes the front end to rise when the wheels are steered off-center so you're actually lifting the weight of the car with the steering wheel). Less stable in Reverse, requiring a little more attention when backing quickly down a long drive, but well worth it IMO for the high-speed improvement.

Long story short, if you'll be dropping the front by 2½" without touching the rear, you'll need more caster shim to keep it driving close to what it does now...but since you probably don't really need them right now, I wouldn't add more unless you don't like it with the one set.

Note that caster shims affect the relationship of the steering box to the column, which stresses the "rag joint". The locating notch on the steering box clamp may need to be opened up to allow it to roll forward. That clamp has a notch on each side because it's used for Beetles and 'Ghias, flipping it 180° allows the box to roll back to better align with the lower column angle on the 'Ghia...which is of no help here.

Also caster shims will reduce the clearance between the tires and the headlight buckets. Less of a problem on `67-up fenders than it is with the early-style headlamps but depending on tire size it could still be an issue.

[risk]

Good info! I will edit my earlier response.

[ps2375]

I'll see how it drives after I install them, as high speed stability is of more importance that steering effort to me. And right now the effort isn't hardly noticeable to me, as I'm pretty much the only driver of it, except when my brother drives it at auto-x's. My wife won't go near it.

Right now it has about a 1/2" rake as measured on the running boards, so it'll increase two or three times that after the spindles are installed, I'm thinking.

[Marc]

I was trying to come up with a simple way to estimate the caster shim thickness required to compensate for a given rake without resorting to using trigonometry and risking people's eyeballs glazing over...I think this "equivalent-triangle" method does the job, but if anyone's got a better idea let's hear it.

Imagine a horizontal line drawn between the centers of the front & rear axles. For a Standard Beetle that line would be 94½" long.

We're assuming that the car is at stock ride height and that the front & rear tires are the same size - if not that can be taken into account later but for now just accept that to keep things simple.

Now visualize moving the front axle center up a given distance...let's say 3" for example...and draw another line between the axle centers. Add a third short line between the original and the new locations of the front axle and you have a triangle.

Now, visualize the equivalent triangle formed at the front beam when it tilts forward with the rake, but in this case the long side is the distance between the beam tubes. For a BJ beam that's 6".

The length of the short side of this little triangle would be proportionate to that of the big triangle.

Now, if you're still with me it's time to do some simple math. Divide the wheelbase into the inches of drop - in this example that would be 3 ÷ 94.5, or .03175.

Multiply that result by the span between the beam tubes (6" for a balljoint front end) to determine how thick of a shim would need to be placed between the lower tube and the frame head to compensate for the rake:

.03175 x 6" = .1905" (a little under 5mm)

SO-O-O-O, theoretically one common ¼" (6mm) shim should be more than enough to put the beam back to its original angle with respect to the ground - and therefore restore stock caster.

Work the problem backwards starting with the ¼" shim: .25 ÷ 6 = .04167.       .04167 x 94.5" = 3.9375"   
....this shows that one ¼" caster shim should suffice for nearly a 4" rake.

As mentioned above, if you're looking for improved straight-line stability at higher speeds you may wish to use thicker caster shims than what the calculations indicate, but this'll give you a good starting point.

[ps2375]

You mean "caster", right?

[andy198712]

My beam bolts scare me though lol never taken them out, thinking I'll buy new ones and take the old ones out and replace with fully greased new items!

[Marc]

You mean "caster", right?

Yes
...I'll go back and edit that, thanks.

[ps2375]

Before:


After:


And I've only done a short drive on the interstate, and having driven that section earlier the same day with it being a windy day, it does feel more planted in the front, the wind wasn't pushing me around like it was before. steering effort doesn't seem to have changed much either. More time and miles will tell.

And headlights/fog lights needed a big adjustment!

[Ol'fogasaurus]

Looks very nice! A "California Tilt" is almost always appreciated looks wise; e.g., not too much and not too little.

The story behind the reason for the "rake" is fun (big/large diameter tires was not the main reason either) especially when the "customs" at the time were either "tail draggers" with "continental kits" or "in the weeds" (a cigarette pack laid on it's side should just barely brush both the pavement and the frame of the car)....

Lee