[DeTomaso] sway or not.

[MikeLDrew at aol.com]

In a message dated 2/25/09 6 41 57, michaelsavga at gmail.com writes:


> How do you adjust the diameter of a bar of steel?  There are different 
> sizes
> and there is hollow and solid, I have never encounted anything else, please
> educate me?
> 

You don't adjust the diameter.   You adjust the length.

Or rather, you adjust the interface between the suspension A-arm, and the end 
of the sway bar, to change the effective length of the sway bar arms, with 
adjustable end links.   Here, a photo is worth a thousand words.   Here's Dale 
Eriksen's factory Gr3 Pantera front suspension:

http://www.poca.com/index.php/gallery/?g2_itemId=4250

Note the link connecting the end of the sway bar to the A-arm.   It is 
heim-jointed on each end to allow great freedom of movement.   The upper link clamps 
around the bar, and it can be slid to any of a number of different positions.

The closer the link is to the end of the bar, the more leverage the 
suspension has to work against the bar, effectively making the bar 'softer'.   In this 
photo, the front suspension is set at the full soft position.   Moving the 
link inwards reduces its leverage, making the front bar 'stiffer'.

Of course, this scheme requires trial and error, adjustment in the pits, and 
then once the suspension is set, it stays there for the duration of the race.

There are other schemes, including cockpit-adjustable sway bars, which are 
really super tricky-dicky.   These work by having a 'blade' on one end, 
controlled with a cable.   The sway bar end is knife-shaped, so that when it is 
standing vertical, it is extremely strong, and when it is horizontal, it is 
relatively flexible.   The rotation of this blade is controlled from the cockpit via a 
knob connected to a cable, so that the driver can adjust the swaybar 
stiffness on the fly.

Here's a photo of such a setup:

http://www.hrpworld.com/client_images/ecommerce/client_39/products/1432_1.jpg

This is in the halfway position.   Here's another image:

http://www.hrpworld.com/client_images/ecommerce/client_39/products/1432_2.jpg

This is the full stiff position.

Neat, eh?

Interestingly, the bar end is usually fixed on one end of the bar and cockpit 
adjustable on the other; having only one side of the bar variable influences 
both sides equally.   That's cosmic, but somehow it works...

Sometimes, cars will have blades on each side, with only one of them 
adjustable from the cockpit; one blade will be rotated to a certain position in the 
pits for the initial rough adjustment, and then the other one will be rotated 
from the cockpit for fine-tuning.   These types of sway bars are used on all 
Trans Am, NASCAR, Grand Am, Le Mans cars etc. etc.

Mike


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