Gee, everyone seems surprised that Cobras had leaf springs in the
front. Yes it's true, at least for the Mark Is and Mark IIs (260cid and
289cid, respectively). In fact, all ACs up to 1965 had leaf springs all
around as far as I know. The chassis was completely redesigned in 1965
for the 427 and did incorporate coil springs.
To help visualize this if you've never seen it, there is one leaf at each
end of the car, mounted transversely; each end of the spring forms the upper
link of the suspension at that corner. So for instance at the front end,
the leaf spring acts as the upper locator, replacing the A-arm at the top,
and there is a ring of metal welded to the end but mounted vertically so
that the kingpin can pivot in this ring. (Spitfire owners will have no
trouble imagining the rear suspension.) The central section of each leaf
spring is firmly mounted to chassis uprights; the rest of the frame is a
modified ladder of round- and square-section tubing that is fairly stiff
for its design era and very light.
While this has some problems when compared to a properly developed long-
lever unequal A-arm setup, it worked far better than the solid axles on
many cars that competed with the AC. In particular, the reduction in
unsprung weight made each wheel respond very quickly on bumps. This
suspension system, by the way, was used even on the Daytona Coupe version
of the Cobras, at least on one of them. At the 20th Anniversary Mustang
show eight years ago last Friday, the Shelby club in southern California
had a number of cars present. Not only GT-350 and GT-500 cars, as would
be expected at a Mustang show, but there were Cobras of all varieties,
including a couple of Daytonas; the bonnet was open on one, so that you
could inspect the front suspension -- not to mention the 390-bhp Cobra
FIA engine with its four 48IDA downdraft Webers and white-ceramic-coated
nest-of-snakes headers. The Daytona Coupe was my favorite car for many
years, and still isn't far from the top of the list. But then, I like
the 289 Cobra's looks much, much better than the 427's.
Probably AC innovativeness was responsible for such an anachronism in a
car of this class. AC was in the best tradition of the small specialty
builder Scott (#1) so eloquently described a while back, using mostly
off the shelf components to achieve superior handling at a cost within
the means of the average bloak. In the early 50's AC came up with a
very successful chassis design for the AC Ace and Acecas.
Ummm... After being referred to so nicely, I hate to offer even the
smallest of corrections, but the transverse-leaf suspension used on the
Cobras (and also cribbed by John Cooper for his first 500cc formula cars
in the mid-Fifties) was originally designed by Fiat, and used on the
Topolino. I can't recall now whether the Topolino was introduced in
1936 or 1937, but its simple transverse-leaf suspension with lower
A-arms revolutionized small-car handling in the Thirties.
This chassis
had transverse leaf-springs front and rear and fully independent
suspension with unequal A-arms. This designed was carried over to the
early Cobras, albeit beefed up a bit. If the designed hadn't worked so
well, I suspect AC would have abandon it early on.
That's right, AC never got bought out by a soul-deadening corporation
that would have refused to make any change that nobody could see...
--Scott "Wishing I had an aluminum V8 and a de Dion rear" Fisher
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