Drop spindles and stock tires?

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SparksLP
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Re: Drop spindles and stock tires?

Post by SparksLP » Sun Mar 18, 2018 12:35 pm

Lee,
So, if you don't lower the rear as well, it affects the geometry of suspension travel and how the tire rubs during turns? If the rear is lowered a similar amount, would that negate some of the changes by making the car more level? I don't know enough about camber/caster etc. so I'll have to do more learning on how that will affect where the tire sits in the wheel well.

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Re: Drop spindles and stock tires?

Post by Ol'fogasaurus » Sun Mar 18, 2018 3:17 pm

SparksLP wrote:
Sun Mar 18, 2018 12:35 pm
Lee,
So, if you don't lower the rear as well, it affects the geometry of suspension travel and how the tire rubs during turns? If the rear is lowered a similar amount, would that negate some of the changes by making the car more level? I don't know enough about camber/caster etc. so I'll have to do more learning on how that will affect where the tire sits in the wheel well.
Sparks, that is what we are here for :wink: .

Can you lower the front w/o lowering the rear... yes, people have been doing it for years but you have to realize than you are changing the geometry designed into the car. I don't think Dr. Porsche planned on what some of us are doing to his cute little Autobahn puddle jumper.

I can't find those other pictures as I think they were taken when my computer was taken over many years ago. Also the Photobucket fiasco has blanked them out also so what I am going to post is going to have to do.
002.JPG
This is a King and Link-pin beam, or what is left of it, after the shock towers were broken off due to a few hard landings (I off-road but I didn't do this). When sitting in a car the beam is laid back roughly 6°.

If you take a ruler and lay it down flat on a table the square end is going to sit at an angle of 90°. If you raised one end of the ruler the other end will not be 90° to the table anymore but laid forward a function of the new angle the ruler now sits at. This is the same thing as putting a "rake" to the car; e.g., lowering the front of the car but leaving the rear at a stock height the angle of the front beam will still be as set into the car but now will not be the equivalent of being laid back 6° anymore. Caster is for going straight ahead better. The lessening of the caster angle makes the car a bit "twitchy"; e.g., more sensitive to turning.

This picture shows the spindle and stock arms at a what would be a compressed (lowered) position such as when you hit a hard bump.
001.JPG
This is in a position of an opposite suspension setting... both are exaggerated to what you would normally have.
DSC04087.JPG
On a ball-joint (BJ) beam this is the adjuster. It is a hex headed piece that the upper ball-joint goes through and together ride in the upper arm of the spindle (see below)
DSC04096.JPG
This shows the complete spindle and arm assembly minus the washers that go under the nuts. The adjuster has a hole drilled off-set on the top but centered in it's bottom so that when the assembly of all the parts are made you can rotate the upper ball-joint via the hex you change angle at which the spindle sits (moving the top of the spindle around) which changes the alignment settings; but again, it has it's limitations as to just how much can be changed.

The new style of adjusters ( or so I have been told) have the upper off-set part of the hole moved over closer to the hex part of the top allowing for more change to the angle of the spindles.

Does this help?
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SparksLP
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Re: Drop spindles and stock tires?

Post by SparksLP » Sun Mar 18, 2018 4:12 pm

So that's why people would use shims, to maintain the stock caster angle if the rear isn't lowered? And the adjuster you mentioned about is built into the spindle to help adjust camber and toe?
And how important is the stock caster angle for safety? Say someone wanted to set up a Bug for autocross, would they want stock caster or a different angle in order to increase handling?
Lots of good info here, thanks!

Ol'fogasaurus
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Re: Drop spindles and stock tires?

Post by Ol'fogasaurus » Sun Mar 18, 2018 7:04 pm

That I can't answer. I think it depends on just how much of caster you lose as well as the size of the course and how many and how tight the turns are. If the steering gets too sensitive then you might have a problem but again, I am not sure.

Back in the late 60's, the 70's and early 80 I belonged to a car club (racing insurance) that eventually morphed into rallying and autocrossing club. Although I never got into (yes, when I was a kid dirt did not exist) either sport I did know some things about each sport j ust by osmosis. Things have changed a lot in both sports since then too.

Lee

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FJCamper
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Re: Drop spindles and stock tires?

Post by FJCamper » Sun Mar 18, 2018 7:27 pm

You want increased caster for high speed stability, and less for autocross.

The more caster, the more resistance there is to turning off a straight line. Daytona and Talladega cars have so much caster they will almost track around the oval banks without a driver.

To really fling a car around a cone track, you need so little caster the car would be dangerous on the street. The front wheels wouldn't return to center coming out of a corner.

Our Historic Sportscar Racing Ghia runs 6 degree of caster up front. At our fastest official timing, we can do 135mph. and that that speed, we are stable.

FJC

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SparksLP
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Re: Drop spindles and stock tires?

Post by SparksLP » Sun Mar 18, 2018 7:46 pm

Ok, I think for my application staying safe and normal is best, haha. I want to build my car so I can drive it on the street, but make it safe enough to maybe run some autocross for fun. I don't care about being competitive, not yet anyway.
So if I do drop spindles, I should realistically try to lower the rear about the same, so caster doesn't become an issue? Assuming that doesn't cause too much camber in the rear, of course.

Ol'fogasaurus
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Re: Drop spindles and stock tires?

Post by Ol'fogasaurus » Sun Mar 18, 2018 7:54 pm

SparksLP wrote:
Sun Mar 18, 2018 7:46 pm
... I don't care about being competitive, not yet anyway....
:roll: :lol:

Sparks, enjoy your build and please stay and contribute what you learn.

Lee

Ol'fogasaurus
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Location: Just north of Seattle

Re: Drop spindles and stock tires?

Post by Ol'fogasaurus » Mon Mar 19, 2018 12:14 pm

Since I have only played with K&L on a minimal basis I forgot I had this.
645575[1].jpg
drscope posted this on The Samba: https://www.thesamba.com/vw/forum/viewt ... p?t=295861 Go to the 4th post down. At the bottom of his post there is a sentence on dropped spindles.
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SparksLP
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Re: Drop spindles and stock tires?

Post by SparksLP » Thu Oct 11, 2018 6:12 am

Haven't posted here for a while. I tried just fitting the drop spindles to my car both with the 185/65r15s on 5.5" wheels and 165r15 tires on stock steel 4.5" wheels. No surprise, both rubbed on the outer fenders. Anyone know what the tallest/widest tire you can run on the stock steel wheels with a stock beam and drop spindles? I'm thinking a 175/65R15 would work, but welcome advice. Application would be street driving.

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