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Cadillac underbody/frame differences over the years.

Started by 64\/54Cadillacking, May 21, 2020, 03:32:28 AM

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64\/54Cadillacking

It has occurred to me that after fully inspecting my 54 Fleetwood, I’ve notice that the frame under the car is very beefy. Not only does it have the typical X-frame but it also has side rails for additional support and extra brackets where the body connects to the frame.

In comparison to my 64, the 64 just has the X-frame with no additional side members for bracing. The rocker panels are heavily reinforced to compensate for the lack of side rails.

Now why would Cadillac go from an extremely strong “Bridge Like” frame that in many ways might possibly be even more rigid and sturdy than a perimeter frame, to an X-frame with less support?

I am not saying that my 64 has a weak body and frame because as a matter of fact it’s a very solid car for being a hardtop, it’s just compared to the 54, the 64 looks less substantial underneath, or I am simply imagining things?
Currently Rides:
1964 Sedan Deville
1954 Cadillac Fleetwood 60 Special
1979 Lincoln Mark V Cartier Designer Series
2007 Lexus LS 460L (extended wheelbase edition)

Previous Rides:
1987 Brougham D' Elegance
1994 Fleetwood Bro
1972 Sedan Deville
1968 Coupe Deville
1961 Lincoln Continental
1993 Lincoln Town Car Signature Series
1978 Lincoln Continental ( R.I.P.) 1978-2024 😞

The Tassie Devil(le)

The simple answer is that by removing the side rails, they could lower the floor way down, thus decreasing the overall height.

Engineers became really good at designing sheet metal in such a way that strength could be retained in a structure, and then the frames could be "slimmed" down, tnd finally removed completely, as in Monocoque construction.   Which is how cars are constructed these days.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

64\/54Cadillacking

Bruce, I didn’t think about the “lower,wider,longer” look at first but you’re right. Compared to the earlier Cads, the later ones with the regular X-Frames sit low inside, while the earlier 50’s Caddys sit much higher up with a massive roofline. The 54 is definitely a more up right driving car, but they still sit really low to the ground.
Currently Rides:
1964 Sedan Deville
1954 Cadillac Fleetwood 60 Special
1979 Lincoln Mark V Cartier Designer Series
2007 Lexus LS 460L (extended wheelbase edition)

Previous Rides:
1987 Brougham D' Elegance
1994 Fleetwood Bro
1972 Sedan Deville
1968 Coupe Deville
1961 Lincoln Continental
1993 Lincoln Town Car Signature Series
1978 Lincoln Continental ( R.I.P.) 1978-2024 😞

Jim Miller

My ‘41 and ‘49 sit high and are as easy to get into as my SRX. Except the 49 has lower roof line and I have to watch my head getting in. The other day a friend let me drive his ‘59. I felt like I was almost down to the pavement. Never realized such a difference before.
Jim Miller

1941 6219
1949 6237X
1970 CDV
2021 XT6
Past:
1991 SDV
1999 DeElegence
2006 DTS
2013 XTS
2016 SRX

fishnjim

Rigidity isn't always something one wants for a variety of reason, ride, crash survival, etc.
Later cars are designed to absorb impact rather than act like two bumper cars.
There were a lot of deaths in the old X-frame era of people being launched like a catapult through the windshield in a crash.   That all lead to the first safety act in '64.   They used to use those old car crash movies to promote seat belts.

savemy67

Hello all,

A few years ago, at the CLC Potomac Region's spring show, three Cadillacs were arranged side by side - one each from the thirties, forties, and fifties.  One of the obvious differences between the cars was the height and width of the bodies.  The thirties car was much taller and narrower than the forties car, which in turn was taller and narrower than the fifties car.

Physics suggests that a higher center of gravity is less stable than a lower center of gravity.  This probably doesn't matter too much if you are traveling at a sedate 40 miles per hour.  But with the advent of higher compression engines, and better roads, road speeds increased.  Car engineers thought a lower center of gravity would give a car better handling at higher speed.

Cadillac went so far as to purchase several Hudson step-down, Monobilt cars to examine a variant of a low-to-the-ground, semi-unit-body constructed car.  While Cadillac decided the Hudson engineered frame/body design was too costly, race car drivers recognized the advantages of a low center of gravity.  Hudsons were the darlings of NASCAR in the early fifties.

Since the inception of automobiles, frame design has been the subject of study, and improvement.  While earlier, design considerations for ruggedness may have been foremost in the engineers' minds, given the low speeds and bad roads of the day, later design considerations emphasized ride, handling and most recently safety.  As Jim noted, today's designs are such that the energy from an impact is absorbed by the cars structure, instead of transmitting the energy from the impact through the structure to the passengers.

Given the apparent demise of the sedan, it seems that today's car market is divided between those who like to ride, and those who like to drive.  I consider my fellow CLC members to be in a unique class - those that like to do both with a bit of elan.

Respectfully submitted,

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

Mike Josephic CLC #3877

Here is what the old reinforced frames on a '55
Cadillac Eldo convertible looked like.  The convertible
frame added about 450 pounds to the weight of
the car.

Yes, the "X frame" design made the styling department
very happy since the "lower, longer, wider" look was
in vogue.  However if you were unfortunate enough to
be "T-boned" in a crash -- you were toast.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

MickeyCaddy

“Longer, lower, wider”...everything has changed so much.

Here’s a pic from three weeks ago; my ‘55 next to a 2020 Corvette C8.

Yes, I’m one parking spot closer to the camera than the ‘Vette, but come on. My ‘55 always looks like a 7/8 scale vehicle when it’s parked next to a modern SUV; but it makes the red C8 looks like a slot car.

Roger Zimmermann

Quote from: Mike Josephic  CLC #3877 on May 22, 2020, 06:36:25 PM
Here is what the old reinforced frames on a '55
Cadillac Eldo convertible looked like. 

It's your car, Mike? Did you see that one muffler collapsed? This is due to the too rigid installation of the exhaust system. When getting hot, the system is getting longer. If the end pipe is not able to slide into the bumper end, something has to go. In this example, the muffler.
I had a similar situation with my '56 Sedan de Ville. Stainless steel exhaust, going through a rubber support in the bumper ends. When hot, the pipes could not slide over the rubber, therefore I had a similar damage. Then I understood why there was a little steel part at the bottom of the rubber: it was there to let the exhaust tube to slide when hot. Fabricated 2 such "spoons" and never had crushed mufflers anymore.
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

gkhashem

#9
I posted this before not all GMs the same. Wonder why the standard of the world did not do this? Yes not a Cadillac but educational and GM so should not be deleted

Starting with its frame. Somewhat curiously, Olds never used the X-Frame, which was used on a variety of GM cars starting in 1957. In 1957-1958, Olds and Buick had used what amounted to a hybrid of the X-Frame and a semi-perimeter frame. For 1959, Buick and Olds diverged frame designs, and Olds used this, still a combination of X and perimeter elements, which was referred to as “Advanced Wide-Stance Chassis”. The side frame rails take the place of the reinforced body sills on the X-Frame cars.

1959 Oldsmobile 98 Holiday Sports Sedan
1960 Cadillac Coupe Deville (CLC Sr #72)
1964 Oldsmobile 98 Town Sedan (OCA 1st)
1970 GMC C1500
1977 Oldsmobile 98 Regency Coupe
1978 Cadillac Coupe Deville (CLC Sr Crown #959)*
1992 Oldsmobile 98 (OCA 1st)
1996 Oldsmobile 98
*CLC Past President's Preservation

Past Cadillacs
1959 Coupe Deville
1966 Coupe Deville (Sr #861)*
1991 Eldorado Biarritz (Sr #838)

Roger Zimmermann

Interesting, I did not or remember that. For 1959, all cars had more or less the same floor (and inner body). Or had Olds a different one to allow the space for the side rails?
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

gkhashem

Quote from: Roger Zimmermann on May 23, 2020, 06:07:53 AM
Interesting, I did not or remember that. For 1959, all cars had more or less the same floor (and inner body). Or had Olds a different one to allow the space for the side rails?

No difference I have one.
1959 Oldsmobile 98 Holiday Sports Sedan
1960 Cadillac Coupe Deville (CLC Sr #72)
1964 Oldsmobile 98 Town Sedan (OCA 1st)
1970 GMC C1500
1977 Oldsmobile 98 Regency Coupe
1978 Cadillac Coupe Deville (CLC Sr Crown #959)*
1992 Oldsmobile 98 (OCA 1st)
1996 Oldsmobile 98
*CLC Past President's Preservation

Past Cadillacs
1959 Coupe Deville
1966 Coupe Deville (Sr #861)*
1991 Eldorado Biarritz (Sr #838)

Mike Josephic CLC #3877

Quote from: Roger Zimmermann on May 23, 2020, 03:53:18 AM
It's your car, Mike? Did you see that one muffler collapsed? This is due to the too rigid installation of the exhaust system. When getting hot, the system is getting longer. If the end pipe is not able to slide into the bumper end, something has to go. In this example, the muffler.
I had a similar situation with my '56 Sedan de Ville. Stainless steel exhaust, going through a rubber support in the bumper ends. When hot, the pipes could not slide over the rubber, therefore I had a similar damage. Then I understood why there was a little steel part at the bottom of the rubber: it was there to let the exhaust tube to slide when hot. Fabricated 2 such "spoons" and never had crushed mufflers anymore.

Hello Roger:

Actually, it's not my car.  It's a photo I "stole" from the
internet.  I used it to illustrate a point about the frame design.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

64\/54Cadillacking

Makes sense, the lower center of gravity does make a car more stable, especially because of how soft Cadillacs rode back then, I bet owners complained of the poor handling as if one always has to constantly correct the steering at every single moment in the early to mid 50’s Cads.

In the 60’s, Cadillac made obvious improvements in suspension geometry. Although my is pretty soft and floaty, it handles great for such a big car. What helps is the “pinky on the steering wheel” steering. It’s so effortless and an easy to drive.

Lowered Styling was obviously what Cadillac was striving for in the 60’s. After owning the 54, I honestly prefer the 54’s styling and it’s seating height over the 64. The 54 feels like a much more commanding car too especially with its massive hood and flying lady as the hood ornament.

The 64 is a low rider in comparison. It’s best of both worlds.
Currently Rides:
1964 Sedan Deville
1954 Cadillac Fleetwood 60 Special
1979 Lincoln Mark V Cartier Designer Series
2007 Lexus LS 460L (extended wheelbase edition)

Previous Rides:
1987 Brougham D' Elegance
1994 Fleetwood Bro
1972 Sedan Deville
1968 Coupe Deville
1961 Lincoln Continental
1993 Lincoln Town Car Signature Series
1978 Lincoln Continental ( R.I.P.) 1978-2024 😞

Cadman-iac

The 50's cars seating position is definitely much higher than the 60's and later models, but as I age, it's also a lot easier to get into and out of because of that. When I had the 69, I was much younger and more able to climb down into it, not that it was that low, but we have several modern cars now, and i just hate to even try getting in or especially out of one of them now.
I have never had the opportunity to drive my 56 yet since it's still in many, many pieces and far, far from being finished, but before I started to disassemble her, I remember that sitting in her was almost like getting into a truck, the way you sit high, and look over the long hood, peering over the ornament. I can imagine just how she feels, and the ride. Lumbering down the road, floating, gliding over the bumps.
I remember the ride my 69 had, and how the 56 Chevy I once had rode, and I imagine that my 56 Cadillac would have a ride like the two combined.
  The 56 seating is higher, like a truck,  but her sides are low, and long, and I would think that she gives you a real sense of security, even if it is false, knowing what we know about safety today.
I was never a fan of the 58 to 64 frames. When I was heavily into the Chevys of the era, I couldn't see how that design could be stable, let alone safe. Not that they are any worse or better than the previous design or the ones to follow.
I recall stories that my dad had told me about how the X frames rode, and what happened if you were hit broadside. I never had any desire to own one after that.
But that aside, they are beautiful cars. A friend had a 64 convertible when I still had mine,  and even knowing what I did about them, I tried to buy it from him.
My son works for a custom car shop and does extensive modifications on them. He had a 60 convertible in for a new engine, a 454, and airbags, and all sorts of other stuff, among them was a trailer hitch for towing a big Air Stream. He said that he had to cut the rear of the frame off behind the axle and fabricate an all new section in order to make it strong enough for the hitch. The original frame was simply too flexible to allow it otherwise.

But I love the look of my 56, and God willing, some day I will get to drive her down the road.

Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Jeepers Creepers

#15
Last time I was servicing ours, I found numbers punched into the frame rails.

A friend suggested it might be for the shims required for the body mounts.

This was around the gearbox area, there was some -20 up by the steering box and on the opposite side rail as well.
All are facing inwards.
Kevin and Astrid Campbell
Australia