Lowering For Handling

[Ol'fogasaurus]

Hi Red hot,

With a driver and full fuel tank, your front trailing arms should sit nearly level. "Nearly" usually means a slight downward slant toward the rear if no luggage or load is present in the trunk.

Lowering the front ride height too much has the same bad side effects on a VW as any other car, loss of ground clearance and loss of suspension travel ... but on a VW it also affects roll, effectively stiffening it, and caster, reducing it.

Too little caster and you wander as you try and drive straight, and you lose your self-centering correction as you transition from a turn into a straight.

Lowering the front end on a swing axle car without an equal drop in the rear promotes dangerous braking and cornering instability. The effect is less on an IRS, but still exists.

FJC

Well said FJC, the part about the caster angle change is so important and is all too often forgotten about especially when dealing with the lowering and raising of a vehicle.

Lee

[papaya]

Ok here's a question for you. I'm building a Manx buggy and the front end on my '69 donor frame is too stiff. The front end has been rebuilt with new parts and I can get it to bounce/mve if I jump on it. The problem is the trailing arms are at about a 4 o'clock down position with just the frame and no body. The Manx body will weigh next to nothing. Even without shocks the front end is going to be rock stiff. What should happen if I removed the grub screw on one of the tubes? will this cause an problem? It will transfer the front weight to the remaining tube. I already have dropped front spindles and the frame still sit level. ?????

[Ol'fogasaurus]

Having one of those days. I have two buggies one for the sand and the other in process of getting ready for the sand. I started doing a beam build here: viewtopic.php?f=28&t=136514&start=105 and about half way down I started dealing with the concept of adjusters but, in my case, only on the upper beam. I got to page 12 and the beam shock towers were just too rusty to continue so I started to go with another beam:

003 - Copy copy.jpg

This is the center piece of t he beam that was removed for the adjuster to be added on the upper beam. It should give you and idea of the shape of the stack of leaves on the BJ beam which is different than the K&L beam. A lot of work to change to K&L but I do have pix for that.

IMG_2452 copy.jpg

This is how the replacement beam sits now.

Some add the adjusters to both upper and lower beams. Some cut and turn the beam locks to either raise of lower the ride but, in my opinion you need to be ready for that due to the weight that may be or may not be there. Remember, it a 10 gallon fuel tank is going to be up front that is roughly 60#s of weight.

leebuggy-12%20copy[1].jpg

I did not change the front BJ suspension for my blue buggy and it rides OK on the sand but probably a bit stiff on the street for any distance driving.

Lee

[papaya]

OK..I get what lowering does. Just lowering the front will not change the hard ride from the springs.
How do I change the spring rate in the front to be more subtle, softer, for a buggy without the metal body.

[Ol'fogasaurus]

OK..I get what lowering does. Just lowering the front will not change the hard ride from the springs.
How do I change the spring rate in the front to be more subtle, softer, for a buggy without the metal body.

Ah ha!, that is why you have an adjuster on the bottom tube of the beam and one on the top tube. You can adjust them to lower the car to the height you want then adjust the upper one to reduce more pre-load. You would probably have to raise the lower one up a bit but that is just part of the tuning of the suspension. The bottom torsion tube does most of the ride but with a little less help from it's friend.

It would be just the same as cutting the rotating the tubes up or down to raise or lower the suspension but this way it is not permanent and you can change things a bit. The adjusters would not allow as much adjustment as the cutting and turning would.

There are a couple of other sneaky tricks that can be done also but that's for another post if needed.

Lee

[buildabiggerboxer]

What would be the handling effects of a 13 inch wheel with a 175/80/ R 13 on it?

david58 well its a great way to lower the front, we did exactly that back in the day and it works well for racing, it can be hard to generate heat in VW front tyres which for racing is critical, todays trend for porsche brakes compounds the problem as they are just too big for even racing and over braking
compounds this problem as you need the brake heat to help in bringing in the tyres, thirteen inch tyres help warm the tyres by more wheel RPM, the only problem is clearing the calipers, some makes clear easily, some not so much but spacer shims normaly correct any caliper interfearence. i say go for it.