1950s 1957 vs 1956 frame design

[Cadman-iac]

I was reading the thread about seat belts in a 59/60 model and when they were first offered. Someone said 57 was the first year.
My question is, was the 57 frame still a typical ladder with an X crossmember like the 56, or was this the year they went to the X frame like Chevrolet did in 58?
The reason I ask, is if the floor pan design was the same as the 56 and the 57 has the same type of frame, the location for the seat belts should also be the same, shouldn't they?

Rick

[Lexi]

Cadmaniac, rather certain that 1957 saw the emergence of the new Cadillac frame. Stripped from the car it looks like a big "X", without the side rails. 1956 was the last year for the "box and X" frame. See attached images of a '57 and a '56 for comparison.  

[Gabe Davis]

What was the point of going to the X frame without the box? Lighter? Stronger? More options for how the body could look?

[Cadman-iac]

  Thanks Clay,
 I just couldn't remember if the 57 Cadillac had the "new" style frame or if like Chevrolet, didn't switch until 58.
 That answers my questions about the floor pan as well. I appreciate your input.

 Gabe,
  What the new X frame was designed for was so the engineers could get the seating position lower and the bodylines as well. It gives the car a lower, sleeker look in effect.
 The problem with this idea was that there was less protection for the passengers in a side impact, as the rocker panel and body side panels took the brunt of any impact.

 Rick

[64\/54Cadillacking]

Cadillac chose lower sleeker styling over durability and safety in 1957 by going with the X-frame.

I read an article somewhere from back then stating where supposedly the torsional rigidity actually increased by Cadillac using the X-frame over the previous box & x-member design. But it seems unfathomable to me in a way.

The X-frame by itself is very heavy especially at the center where most of its strength is located. Cadillac went away from using the X-frame for safety reasons and weight saving measures starting in '65 with the simple perimeter frame which shaved off about 200-250lbs from the curb weight of the 1965 cars over the previous model years.

IMHO, the frames that Cadillac used up until '56 ( fully boxed, with big X-bracing and multiple body mounting points) has to be one of the strongest, overbuilt frames they ever made. They are tough, extremely durable and the frame itself is larger in overall size than the standalone X-frame and Perimeter frame they used later on.

The beefiness of my '54 Fleetwoods frame totally makes the X-frame under my '64 seem so minuscule.

[Lexi]

Cadillac chose lower sleeker styling over durability and safety in 1957 by going with the X-frame.

I read an article somewhere from back then stating where supposedly the torsional rigidity actually increased by Cadillac using the X-frame over the previous box & x-member design. But it seems unfathomable to me in a way.

I also remember reading that and it seemed unlikely to me as well. Perhaps it was just "gobble-d-gook" to help sell cars. Clay/Lexi

[Eric DeVirgilis CLC# 8621]

A lot of things go against conventional wisdom.

[Cadman-iac]

Cadillac chose lower sleeker styling over durability and safety in 1957 by going with the X-frame.

I read an article somewhere from back then stating where supposedly the torsional rigidity actually increased by Cadillac using the X-frame over the previous box & x-member design. But it seems unfathomable to me in a way.

The X-frame by itself is very heavy especially at the center where most of its strength is located. Cadillac went away from using the X-frame for safety reasons and weight saving measures starting in '65 with the simple perimeter frame which shaved off about 200-250lbs from the curb weight of the 1965 cars over the previous model years.

IMHO, the frames that Cadillac used up until '56 ( fully boxed, with big X-bracing and multiple body mounting points) has to be one of the strongest, overbuilt frames they ever made. They are tough, extremely durable and the frame itself is larger in overall size than the standalone X-frame and Perimeter frame they used later on.

The beefiness of my '54 Fleetwoods frame totally makes the X-frame under my '64 seem so minuscule.

 I would have to agree, the 56 frame, boxed, crossed and tapered, is the best one I've ever seen.
 Even my old truck frames can't compare.

 As for the 57-64 X frames, I guess there might be less flex, or twist, due to that huge center section and the boxed rails extending from it. But safety, I don't think so.
 I know that's why they went with the perimeter frame in 65. Even just the "C" channel on the sides is better than  just the rockers and doors in an impact.

  Rick

[64\/54Cadillacking]

I also remember reading that and it seemed unlikely to me as well. Perhaps it was just "gobble-d-gook" to help sell cars. Clay/Lexi

Exactly. I thought the same thing.

[64\/54Cadillacking]

I would have to agree, the 56 frame, boxed, crossed and tapered, is the best one I've ever seen.
 Even my old truck frames can't compare.

 As for the 57-64 X frames, I guess there might be less flex, or twist, due to that huge center section and the boxed rails extending from it. But safety, I don't think so.
 I know that's why they went with the perimeter frame in 65. Even just the "C" channel on the sides is better than  just the rockers and doors in an impact.

  Rick

In many ways, the 57-64 X-Frame Cads had to have the rockers heavily reinforced with extra steel because of the lack of side rails. Much stronger than say a typical X-Frame Chevy of era which probably flexed a lot driving over uneven road surfaces. I know that guys that turn these old X-frame Chevies into low riders have to reinforce parts of the frame and body because they would cause problems when the cars were installed with hydraulics when they would hop them.

These frames look much stronger than modern frames! Built like a bridge girder. 🌉💪🧱


   

[Cadman-iac]

  Wow, that's interesting reading, and advertising on the Cadillac frame. What is this out of, an ad, or a brochure for the car itself?
Thanks for posting it.
I'd like to see how these held up in a crash. Unfortunately there aren't many, if any still in the wrecking yards to look at anymore, and those that are are probably stripped to the point that you couldn't really tell much from them.
I've often wondered about what if you added some of the more modern safety features to an older vehicle. For instance, the door impact reinforcement bars. I did this for my 64 truck using 1x2" heavy wall tubing. I put two into each door, spaced about 16 inches apart and welded into the door shell near the hinge locations, and with the 1" facing out so that it has more strength.
I've looked at the 54-56 Cadillac doors, and there's really not much that would protect you in the case of a side impact.
Can you imagine an old Cadillac from the 40's or 50's with all the airbags and crumple zones?
Me either! But there's some things that you could do that wouldn't be obvious to the casual observer, like impact bars in the doors.
Honestly, I don't believe that there's much if anything that you could do to improve the frames though. Short of building a Nascar style cage that is, and that kinda defeats the reason for driving an old Cadillac.
Good post on the frame design.

Rick

[64\/54Cadillacking]

Wow, that's interesting reading, and advertising on the Cadillac frame. What is this out of, an ad, or a brochure for the car itself?
Thanks for posting it.
I'd like to see how these held up in a crash. Unfortunately there aren't many, if any still in the wrecking yards to look at anymore, and those that are are probably stripped to the point that you couldn't really tell much from them.
I've often wondered about what if you added some of the more modern safety features to an older vehicle. For instance, the door impact reinforcement bars. I did this for my 64 truck using 1x2" heavy wall tubing. I put two into each door, spaced about 16 inches apart and welded into the door shell near the hinge locations, and with the 1" facing out so that it has more strength.
I've looked at the 54-56 Cadillac doors, and there's really not much that would protect you in the case of a side impact.
Can you imagine an old Cadillac from the 40's or 50's with all the airbags and crumple zones?
Me either! But there's some things that you could do that wouldn't be obvious to the casual observer, like impact bars in the doors.
Honestly, I don't believe that there's much if anything that you could do to improve the frames though. Short of building a Nascar style cage that is, and that kinda defeats the reason for driving an old Cadillac.
Good post on the frame design.

Rick

Rick, I got those pics from the data book online (GM heritage center).

I know, I could only imagine how much safer our Cads would be if they did have air bags, and other added modern safety features.

Actually after reading more into Cadillac frames, there was an article from curbside classic stating from an old Car Life mag article from 1964 by Roger Huntington  stated how GM's X-frames were pretty heavy and more rigid than the perimeter frames that came out in '65 and was also more torsionally stiffer than the '56 on down Cadillac I-Beam X-Frame. The 57-64 X-frame was also very expensive to produce.

The old '56 frames weighed a lot
as well at 393lbs, but the stand alone X-Frame in the Cadillacs weighed 410lbs, but it's beam stiffness was raised 41%.

But sometimes having an ultra rigid chassis can cause problems with ride quality.

The Perimeter frame weighed a lot less, cost less to manufacture, and was less rigid than the previous Cadillac frames, but it allowed more flex so when driving  over rough roads, the frame acted like a 2nd or 3rd suspension. This added flexibility in the frame, which allowed the car to take bumps and uneven road surfaces without creaking and rattling.

But because the perimeter frame was less stiff than previous Cadillac frames, the bodies had to have extra reinforcements to prevent body flexing which could cause misalignments.

Anyway, I'm rambling along here lol. I just feel like no matter what Cadillac someone owns, it's still much better to have a full frame underneath the body of a car than none at all. This is why no matter how well engineered a unibody vehicle is, no matter how much sound deadening materials is used to quiet the car, a full frame car will still ride smoother, feel more durable, and absorb bumps and vibrations better than any frameless vehicle can.

It's simply a matter of physics, when a force or energy is transferred to an object, that force of energy has to exit somewhere. So car bodies without a full frame, harsh vibrations from a force is transmitted into the cars body which you can easily feel, but a fully framed vehicle that is tuned for comfort, can easily handle those forces with the frame acting like a deflector therefore the vibrations are reduced and or not even felt in the cabin.

Common sense stuff really haha.



 

[Cadman-iac]

Yes, all that is so true. I've owned a few unibody vehicles, and they suck in my opinion. Everything is difficult to work on, hard to get at, and way over complicated.
I told my wife that when her car finally bites it, she's getting a truck, because I'm not gonna screw with another front wheel drive unibodied car. Too damned old and stiff to put up with it now.
Thank you very much for taking the time to post this information, I really enjoyed reading it.

Rick
Edit: I noticed that the pages on your last post were not consecutive, the story was hard to follow.
 Is there a page missing maybe?

[Cadman-iac]

 As heavy and thick as the 56 frames are, it's hard to imagine that they would flex much, especially in the middle between the front and rear wheels where the big X is, but I guess it's possible.
 The way that article explains why the 57 X frame was designed to eliminate flex, you could get the impression that the 56 and earlier frames had excessive amounts of flex resulting in cracked bodies around the mounting points. But at least with mine, there's absolutely no evidence of any cracks anywhere.
 My father in law had a 63 Impala that my wife had driven regularly, and she always complained that it rode way too soft and bounced a lot. She and her dad always attributed it to the frame design, which was the same as Cadillac's was.
 But I've never had an opportunity to drive a car with the X frame design, so I can't really say if it made any difference or not in ride quality.
 
  Rick

[64\/54Cadillacking]

Yes, all that is so true. I've owned a few unibody vehicles, and they suck in my opinion. Everything is difficult to work on, hard to get at, and way over complicated.
I told my wife that when her car finally bites it, she's getting a truck, because I'm not gonna screw with another front wheel drive unibodied car. Too damned old and stiff to put up with it now.
Thank you very much for taking the time to post this information, I really enjoyed reading it.

Rick
Edit: I noticed that the pages on your last post were not consecutive, the story was hard to follow.
 Is there a page missing maybe?

Thanks Rick I appreciate that.

Unibody vehicles are simply a cheap way of building a car. They also need more sound deadening materials and padding to absorb road noise, unlike a fully framed car that needs less of those materials to be quiet on the road. My '07 Lexus LS 460L rides very smoothly mainly because it has air suspension and is long wheelbase model which is a bit funny since a 121.7 inch wheelbase isn't long at all IMO 😆 owning old Caddy's for years, that seems a bit short. So although it rides smooth for the most part, it doesn't compare at all in terms of road isolation, pothole and rough road absorption like how my '64 Caddy and or my '78 Lincoln Continental rides which still blows away the Lexus as far as comfort goes. But compared to other modern cars on the road, the Lexus rides superior to them.

Rick, I am not sure about my last post not being consecutive? Did I miss something? My apologies if I did. Sometimes I can get carried away in a discussion and go back and forth about a subject lol. I took screenshots from that old curbside classic article, here's the link if you want to read more into it maybe that will help.

https://www.curbsideclassic.com/automotive-histories/tech-history-vintage-article-the-perimeter-frame-body-and-frame-not-body-on-frame/


 

[64\/54Cadillacking]

As heavy and thick as the 56 frames are, it's hard to imagine that they would flex much, especially in the middle between the front and rear wheels where the big X is, but I guess it's possible.
 The way that article explains why the 57 X frame was designed to eliminate flex, you could get the impression that the 56 and earlier frames had excessive amounts of flex resulting in cracked bodies around the mounting points. But at least with mine, there's absolutely no evidence of any cracks anywhere.
 My father in law had a 63 Impala that my wife had driven regularly, and she always complained that it rode way too soft and bounced a lot. She and her dad always attributed it to the frame design, which was the same as Cadillac's was.
 But I've never had an opportunity to drive a car with the X frame design, so I can't really say if it made any difference or not in ride quality.
 
  Rick

I actually think that the '56 and earlier frames, are very strong and rigid. The only reason why Cadillac and other GM makes went with the X-frame was strictly for styling purposes. They wanted to keep lowering the car body's but also not have a high footwell.

The '56 and earlier models were much taller cars, so the older frames worked perfectly fine. The body's are still strong, as times I've taking my '54 out to drive, it doesn't creak or rattle at all.

The Cadillac X-frame in '57 had only 200lbs increase in torsional rigidity over the previous frames, but its beam strength was greater however. So it's not much more "rigid" over the older frames, only slightly.

I do think when Cadillac or even Chevy for that matter went away from the rear leaf suspension and had rear coils with the upper yoke style ball joint arm right above the rear axle, this was probably when Cadillacs had the most "float" to them as the rear suspension was able to articulate better than the later upper trailing arms starting in '65 which increased handling and reduced sway.

[Cadman-iac]

 I can see that. The leaf springs will only flex just so far, and the 4 link does a really good job of letting the axle "float" under the car.
 I remember the ride that my 69 Deville had. I used to refer to it as "front end controlled" because the car tilted and tipped whichever way the front wheels contacted the road, but the rear end just floated and flopped around under the car without really causing it to tip or dip the same as the front wheels would do to it.
  Thanks for your comments.

 Rick

[64\/54Cadillacking]

Very true Rick. Here's a pamphlet comparing the '54 Cad to the '54 Chrysler New Yorker and Imperial in terms of features and frame design which are essentially the same for the '56 Cads. I thought you might like it.


     

[Cadman-iac]

  That is a very interesting comparison with Chrysler. I like the disclaimer on the bottom of the first page, "from sources considered reliable, it's accuracy is not guaranteed". But I'll bet it's more so than what Chrysler put out the same year.
 The amount of glass difference is pretty high too. Lots of interesting facts and sales points.
 Thank you for that. I did enjoy reading it.

 Rick

[Roger Zimmermann]

Don't forget that for 1954 Cadillac had a new body and the one for Chrysler was at its end. They had new bodies for 1955.