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Re: Speaking of upgrades...

To: "Denise Thorpe" <xyzabcde@earthlink.net>, mgs@autox.team.net
Subject: Re: Speaking of upgrades...
From: Barney Gaylord <barneymg@ntsource.com>
Date: Thu, 05 Jul 2001 22:39:15 -0500
At 08:54 PM 7/5/2001 -0400, Denise Thorpe wrote:
>....
>I've often thought of putting in a larger sway bar, but I love the way my
car handles and I would hate to make it handle in some way I don't like.
For example, I tried delrin A-arm bushings in my car (custom-made by a
machinist friend long before they were generally available) and the ride
was too harsh for me.  The MGBGT V8 bushings it has now are just right.  So
the question is, can anyone tell me how a slightly larger sway bar would
effect the handling?  Would it make the car handle like it does but more
so?  Or would it make the ride rough? 

A 1976 RBB with a (sort of stock) 5/8" front bar from a later year and no
rear bar, making a hard turn on street tires:
    http://www.chicagolandmgclub.com/photos/warrax01/1595.jpg
Body roll is a bit excessive for my taste, but it rides and handles okay
for casual street use.

A 1967 CBB with the stock 9/16" front bar and street tires.
    http://www.chicagolandmgclub.com/photos/siemens00/siemens3.jpg
Notice the outside font tire tucking under slightly as the inside fender
lifts.  This is a particularly harsh manuver which causes understeer
(push), where the front tires tend to skid sideways rather than turning the
way you would like.  For better handling a stiffer front bar would be a bit
better.

A TD turning in hard:
    http://www.chicagolandmgclub.com/photos/warrax01/1590.jpg
Totally inadequate roll stiffness, but that's the way they are (or were).

My MGA with a 3/4" front bar turning hard on race tires:
    http://www.chicagolandmgclub.com/photos/siemens00/barney.jpg
A stock CBB would have similar characteristics.  This one is catching air
with a rear tire, but it's a little misleading.  The race tires generate so
much additional side force as to increase the body roll considerably.  For
original type bias ply tires the late production 5/8" factory front bar is
about right for good handling (just that the tires have poor grip by modern
standards).  For modern street type radial tires the 3/4" front bar is just
the berries, providing a very nice combination of ride and handling, and it
keeps the rear tire down fairly well.  Refer to the picture of the CBB above.

For use with the sticky race tires and autocrossing I find my new 7/8"
front sway bar does a much better job, but it is just a bit of overkill for
use with street tires, and adds some noticeable harshness to the ride
quality (but not objectionable to me).  Simply adding poly bushings to the
3/4" bar can increase the roll stiffness noticeably without increasing
harshness (much).

The most important thing you get with a larger front sway bar for road use
is improved steering response.  When you give the steering wheel a little
twist the car turns in a little quicker, which gives it a much more
sporting feeling of crisper handling, and the decreased body roll gets it
through a salolom quicker with less bouncing around and less tail wagging.
Theoretically too much front sway bar will lead to once again increased
understeer (pushing), but the stock rear leaf springs on my MGA are so
stiff that even with the 7/8" front bar I have not encountered that
problem.  I just love it!  But still the 3/4" front bar is very nice for
street use and less harsh than the 7/8" bar.

Barney Gaylord
1958 MGA with an attitude
    http://www.ntsource.com/~barneymg

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