X-Frame History - help

[X-Frame]

An X is an X except when it isn't an X… have you met one of my X's?

Seriously folks, a colleague and myself are putting together information for a book about the history of the automobile X-Frame chassis (hence my user ID).

In a broad stroke generality, American cars built between 1932 until about 1965 were built with one form of X frame or another and they were often configurations almost looking like other letters and called many different things.

We have found the world's first use in a automobile dating back into the early 1920s in France and centering in on the "last" use. In America the last holdouts were the Buick Riviera (until 1970), the Checker (until 1982), and a few specialty cars such as the Delorean which had a more "backbone" X. There were others especially foreign that date later but… I am asking for those who may want to chime in on if they know of the "last" use of an X in any vehicle rather it be automobile, SUV, truck, or military?

I recently saw "Spiderman 3" which has a scene of some AM General Humvee's overturned and we can see the chassis of one but it clearly had an X frame… but Humvee's don't have an X - or do they (one model or another?) Or was this only a computer generated fantasy car and not accurately depicting a real vehicle? And why would they have chosen an X frame configuration that looks similar to the mid 1950s Chrysler convertible frame?

Comments?

[CarlLaFong]

I think you are confusing X or K shaped center crossmembers, which are very common, with the late 50s GM X frame. Nearly all automobile frames, from the beginning until the present (trucks, mostly), use a variation of the ladder frame. I could be wrong, but I have never seen a 30s through early 50s American car with a true X frame, certainly none of the Big 3

[X-Frame]

I think you are confusing X or K shaped center crossmembers, which are very common, with the late 50s GM X frame. Nearly all automobile frames, from the beginning until the present (trucks, mostly), use a variation of the ladder frame. I could be wrong, but I have never seen a 30s through early 50s American car with a true X frame, certainly none of the Big 3

I am afraid you are incorrect. I can point you to hundreds of examples but just for one here is a 1934 Buick chassis and will note they even call it an X brace...

[ply33]

I think you are confusing X or K shaped center crossmembers, which are very common, with the late 50s GM X frame. Nearly all automobile frames, from the beginning until the present (trucks, mostly), use a variation of the ladder frame. I could be wrong, but I have never seen a 30s through early 50s American car with a true X frame, certainly none of the Big 3

The frame of my '33 Plymouth has an X shaped center piece and the sales literature mentions it as a "X Frame". Does that count as a "30s through early 50s American car with true X frame"? Or is a "true X frame" something different. Here is another person's '33 Plymouth chassis where you can see the X:

[X-Frame]

The frame of my '33 Plymouth has an X shaped center piece and the sales literature mentions it as a "X Frame". Does that count as a "30s through early 50s American car with true X frame"? Or is a "true X frame" something different. Here is another person's '33 Plymouth chassis where you can see the X:

David, I am wondering if 58Mustang is confusing X with X-Body style frame? Yes, your 1933 Plymouth is a "true" X-frame. Even the ones for GM starting with the 1957 Cadillac and continuing on with the 1970 Buick Riviera, is also a X frame. It is called a Tubular Center Section X Frame and some call it a Cruciform Frame.

To us a K frame would be like that on the 1959-1960 Buicks and if he is thinking of early 1930's Chevrolet, Pontiac, etc... then those were different and called YK frames. I can list exactly which year each started with true X frames...

Buick - 1933

Cadillac - 1934

Chevrolet had the YK frames in 1934-1935 except the Standard model which had an X in 1935 only then started with X on convertibles in 1941. the 1940 convertible had a unique 1-year only K type.

Oldsmobile - 1933

Pontiac - YK 1934-1936 then X in 1937

And that is just the GM cars.

To elaborate, some of the earliest American cars to have a true X frame were:

Cord 1929-1932 (the 1936-1937 models were unibody design)

Auburn 1931-1936

Hudson, Terraplane, Essex, Nash, Packard and the Studebaker offshoot Rockne all started in 1932 with true X frames.

Chrysler products had X frames starting in 1932 but they are a bit unique to me as they look more like a VC configuration as the two rear legs are short and a bit curved which was short-lived. That would include the 1932 Plymouth, David and the 1933 you have changed to a true X.

Eric

[*NOTE... Correction, seems to be 58Mustang's interpretation of X frame that is a bit skewed. Yes, all of the earlier X frame cars had a ladder type frame with center brace but in lamens terms and those listed by many manufacturers in their materials theses are simply called X-Frames. A ladder frame is normally considered one that has perpendicular cross members in multiple places along the length of the side rails - like a household ladder and used more commonly pre 1932 and post 1964 and normally in trucks]

Edited January 19, 2012 by X-Frame (see edit history)

[ply33]

David, I am wondering...

Eric

Actually I'm not David. I just linked to a photo he took.

Someplace I probably have an equivalent photo of my car's frame but it isn't available on line at the moment.

[Dave@Moon]

It's always been my understanding that the X shaped crossmember in some frames, although apparently enough early on to be called an "X frame", was of late only considered a type of crossmember and not the defining aspect of the frame. I've always heard "X frame" used to refer to a frame in the shape of an "X" with no side rails, as in the 1958-1964 Chevy ( http://www.xframechevy.com/ ) and many Lotus models.

[X-Frame]

Actually I'm not David. I just linked to a photo he took.

Someplace I probably have an equivalent photo of my car's frame but it isn't available on line at the moment.

No problem.

Now that we have established a baseline interpretation and industry firsts... let's get back to figuring out which were the "last" with this configuration with or without side rails

[X-Frame]

It's always been my understanding that the X shped crossmember, although apparently enough early on to be called an "X frame", was of late only considered a crossmember. I've always heard "X frame" used to refer to a frame in the shape of an "X" with no side rails, as in the 1958-1964 Chevy ( http://www.xframechevy.com/ ) and many Lotus models.

I can see your confusion and with what we are doing is trying to explain these various interpretations that have come along. In genral, if it has a X center brace then it is considered a X-Frame - with or without side rails. There are a lot of variations out there like the Lotus example you gave. The rare 1967-1970 Toyota 2000GT frame is almost exactly like the Lotus and this variation of the X frame is called a "backbone" X.

The one you gave above for GM cars is the tubular center section X frame and I even spoke with its designer a couple years back. He was in his 80s but told me some background about it. US Patents are also on some of these various designs and again, referenced as X Frames but like 58Mustang eludes to sometimes referred as X-Braced. The 'X' is the key for ALL of them. Are you confused yet? :confused: The history and sorting out the designs and how it was part of automotive history will be explained in our book.

BUT... still asking anyone for examples of "last" ones like these.

[Guest]

It's always been my understanding that the X shaped crossmember in some frames, although apparently enough early on to be called an "X frame", was of late only considered a type of crossmember and not the defining aspect of the frame. I've always heard "X frame" used to refer to a frame in the shape of an "X" with no side rails, as in the 1958-1964 Chevy ( http://www.xframechevy.com/ ) and many Lotus models.

________________________________________________________________________

My belief too Dave, A true X with no side bracing. 1958-64 Chevy and 1958-60 Pontiac's.

The reason I say a true X is because the X alone frame above is the whole unit, where as the picture in the #3 thread the X is just the adjunct to the the main perimeter frame...It's merely for rigidity bracing . This is also self evident because the X is drilled or stamped full of holes, meaning it's not there to carry weight.

D.

Edited January 20, 2012 by helfen (see edit history)

[X-Frame]

Maybe my word "true" is throwing people off here? When I say TRUE I am meaning that the center section is shaped in a X configuration and not a K or YK or other configuration.

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This means with or without side rails.

We have been studying this for years and this is how we are going to present it especially when the manufacturers at the time also indicated the same. Yours is only one belief and we will try to embrace yet dispel some of them.

Edited January 20, 2012 by X-Frame (see edit history)

[CarlLaFong]

I am afraid you are incorrect. I can point you to hundreds of examples but just for one here is a 1934 Buick chassis and will note they even call it an X brace...

I am afraid that I am, very much, correct. The picture that you have posted is a ladder type frame with an X shaped crossmember, not an X frame. The picture that Dave Moon posted is an X frame. The terms, X brace or X member do not equal an X frame. Please point me to hundreds of examples of true, pre 1958, X frames, that is, a frame that does not have full length side rails and is a true X shape. I will cue up the theme from "Jeopardy"

[ply33]

It's always been my understanding that the X shaped crossmember in some frames, although apparently enough early on to be called an "X frame", was of late only considered a type of crossmember and not the defining aspect of the frame. I've always heard "X frame" used to refer to a frame in the shape of an "X" with no side rails, as in the 1958-1964 Chevy ( http://www.xframechevy.com/ ) and many Lotus models.

Being ignorant of cars of the 50s and 60s, your image has now explained to me some of the comments about the '59 Chevy crash test video that was floating around a while ago. I couldn't understand why a X frame could be weaker in a front offset crash than a conventional ladder frame. Of course I was visualizing an X frame as implemented in my '33 Plymouth which has full length side rails, not a frame like your image shows. I can see now how that frame structure could be inadequate for dealing with such a collision.

[X-Frame]

I am afraid that I am, very much, correct. The picture that you have posted is a ladder type frame with an X shaped crossmember, not an X frame. The picture that Dave Moon posted is an X frame. The terms, X brace or X member do not equal an X frame. Please point me to hundreds of examples of true, pre 1958, X frames, that is, a frame that does not have full length side rails and is a true X shape. I will cue up the theme from "Jeopardy"

Sorry, you are only one person with one belief and can't see the big picture of what I am saying. You have to be more open minded. I can and will post some examples a little later per the manufacturer's descriptions. There are dozens of variable design X frames out there and X-Frames is the catagory But then again I guess you will question even the maker's descriptions huh???

[Guest]

Sorry, you are only one person with one belief and can't see the big picture of what I am saying. You have to be more open minded. I can and will post some examples a little later per the manufacturer's descriptions. There are dozens of variable design X frames out there and X-Frames is the catagory But then again I guess you will question even the maker's descriptions huh???

__________________________________________________________________________

A true X frame stands alone with NO other support.

[CarlLaFong]

When you say "X Frame", most car guys, immediately, think of the 58 and later GM X Frame. In 32, Ford began using a "K" shaped crossmember, yet I have never heard them called "K Frames". If you look at any road tests of early cars, in the specs, you will see most as having ladder frame construction. The use of the term "X Frame" as a broad brush term is incorrect. It is not an industry standard term. All automatic transmissions are not Hydomatics. Sure, Plymouth may have touted it's all new X Frame and all of it's benefits, but guess what?, Floating Power doesn't really float. When you can show me "X Frame" as a term and description that has a specific definition that is recognized and used by auto engineers as a whole, I will deign to your newly minted term

[jscheib]

I agree with 58Mustang, only true no side rails should be considered X frames, in my opinion. But this is all "unofficial", and perhaps marketing. Does anyone know what the SAE has to say about this subject, or do they not address it?

And, by the way, I have one of each true example, ladder and X. Is there anything like a true x with side rails and no perpendicular "rungs" whatsoever?

John

Edited January 20, 2012 by jscheib (see edit history)

[Guest South_paw]

Cadillac called it an X member

[Dave@Moon]

I can see now how that frame structure could be inadequate for dealing with such a collision.

I'm at a loss to think of any collision for which this design would be adequate. :eek:

[Guest]

I'm at a loss to think of any collision for which this design would be adequate. :eek:

___________________________________________________________________________

Correct Dave. While Chevrolet (1958-1964) and Pontiac (1958-1960) used them, other GM family members did use the X frame but also used side frame rails. Interesting that in 61 Buick went to the X plus finally a open two piece driveshaft and Pontiac went to the perimeter. I remember talk about how good these frames were in regards to strength and how bad the were if you were unfortunate to get in a center punch type of accident-a lot of intrusion to the very center of the car. The 1961 Pontiac's used the new perimeter frame to channel the bodies between the rails and to eliminate the two piece driveshaft of the old X frame and go from a three link rear end to a four link. This also made the cars lower and stronger.

D.

[West Peterson]

When you say "X Frame", most car guys, immediately, think of the 58 and later GM X Frame.

I disagree.

[X-Frame]

Thanks West. When a well known publisher agrees then you know there is something to it

I first must apologize to 58Mustang for my rants yesterday. When I get started sometimes I don't know when to stop especially in the heat of the moment while talking about something which is a passion… Sorry John.

　

Second, it can be summed up as semantics. Yes, a lot of companies called their chassis X-Braced or X-Membered or even X-Type but you can lump it up as a X-Frame. Heck, I even saw Oldsmobile call their "new and improved" chassis a Dreadnought . But rather than clutter the thread up with examples I want to cite, it would be easier to show you what Cadillac called the "X" you refer to as they were the originators of it in 1957. The chassis was designed for the Eldorado Brougham but at the last minute they used it on the entire Cadillac line. Without giving away too much, GM was aware that they had an issue with the chassis but it was also Fisher Body who wasn't ready either

　

As I mentioned, they call it a "Tubular Center X" Frame and not simply a X Frame.

　

As for a X that has no cross bracing… there isn't one that I know of outside of some patents I have seen. You would need at least some for engine-transmission support. Also, it would not be very stable without it having too much "twist" which is just what the X was originally designed for, torque issues, but you still need the added support of cross members (rungs as you called them). There are some very minimalist frames though with only the needed cross members.

1957 Eldorado Brougham and 1958 Cadillac is below.

Eric

Edited January 20, 2012 by X-Frame (see edit history)

[X-Frame]

When you say "X Frame", most car guys, immediately, think of the 58 and later GM X Frame. In 32, Ford began using a "K" shaped crossmember, yet I have never heard them called "K Frames". If you look at any road tests of early cars, in the specs, you will see most as having ladder frame construction. The use of the term "X Frame" as a broad brush term is incorrect. It is not an industry standard term. All automatic transmissions are not Hydomatics. Sure, Plymouth may have touted it's all new X Frame and all of it's benefits, but guess what?, Floating Power doesn't really float. When you can show me "X Frame" as a term and description that has a specific definition that is recognized and used by auto engineers as a whole, I will deign to your newly minted term

Even these early Fords you speak of will fall into a variance of the X in our book. Though they look like two bows linked in the center rather than straight line X, they still fall within the peremiters of the catagory. Ford started using this in 1933. The 1932 Ford had a ladder frame. Not sure what you are referring to as a K frame in 1932... example please If anyone has SAE info to post, please do.

Below is an example of the 1933 Ford frame out of a crazy 3-D brochure they made then but you can see they say it is a X type frame. I double checked and the 1932 is a ladder frame.

Another rare example of an X that I am sure would be disputed sat under the Totota Crown models of the early 1960s. It was massive and looks more like a H but it does bow towards the middle and Toyota calls it a X Frame.

Eric

[Guest Jim_Edwards]

I'm at a loss to think of any collision for which this design would be adequate. :eek:

There would be none!

GM's "X" frame first appeared in 1957 on Cadillacs and should not in anyway fashion or form be confused with a ladder frame having "X" or "K" bracing. Candidly in my view it is a perfect example of cheapening a product without regard to anything other than the bottom line. They virtually spawned a whole new service business to bring them into square. Isn't hard to twist one of those suckers by just jacking it up to change a tire. Engineering crap!

[X-Frame]

There would be none!

GM's "X" frame first appeared in 1957 on Cadillacs and should not in anyway fashion or form be confused with a ladder frame having "X" or "K" bracing. Candidly in my view it is a perfect example of cheapening a product without regard to anything other than the bottom line. They virtually spawned a whole new service business to bring them into square. Isn't hard to twist one of those suckers by just jacking it up to change a tire. Engineering crap!

You got to remember that the old high profile cars of the 1940s was now outdated and with each new year the manufacturers tried to lower and lower the car's height. To accomplish this they needed to drop the body between the rails and that was next to impossible with a perimiter frame with an X without sacrificing some leg room too. That is only one of the main reasons the 1957 style GM frame was developed. For lower, sleeker, more modern cars of the "jet and space" age. Different mindset then and automobile testing wasn't as complex as it is today. It was more about looks than safety. All GM (except the Buick Riviera) had abandoned this frame by 1965 to a boxed corner perimeter frame more wide open in the center to drop the body as low as they want and for safety reasons.

To be fair, Ford stopped using the X except in Convertibles in 1949 but Lincoln didn't stop until the new 1958 unibody design, Chrysler products stopped around 1941 except for convertibles.

Eric

[Guest]

You got to remember that the old high profile cars of the 1940s was now outdated and with each new year the manufacturers tried to lower and lower the car's height. To accomplish this they needed to drop the body between the rails and that was next to impossible with a perimiter frame with an X without sacrificing some leg room too. That is only one of the main reasons the 1957 style GM frame was developed. For lower, sleeker, more modern cars of the "jet and space" age. Different mindset then and automobile testing wasn't as complex as it is today. It was more about looks than safety. All GM (except the Buick Riviera) had abandoned this frame by 1965 to a boxed corner perimeter frame more wide open in the center to drop the body as low as they want and for safety reasons.

To be fair, Ford stopped using the X except in Convertibles in 1949 but Lincoln didn't stop until the new 1958 unibody design, Chrysler products stopped around 1941 except for convertibles.

Eric

_______________________________________________________________________

As I read in my 61 Pontiac service manual and the Motor Trend magazine where Pontiac is named car of the year they both say Pontiac went from the 58-60 X frame to the new perimeter frame for various reasons. Safety in side collisions, lowering the body between the frame rails to lower the car for better stability and deepening the floor foot well area and more economical to manufacture because the exhaust doesn't have to be run through the frame, a one piece drive shaft instead of a two piece with a center bearing and the frame is lighter and cheaper to manufacture. My 62 Catalina has much more room underneath the car than my 59 did. The exhaust is a breeze to put in compared to my 59 where the exhaust had to be bent and assembled in pieces through the holes in the frame.

D.

[X-Frame]

_______________________________________________________________________

As I read in my 61 Pontiac service manual and the Motor Trend magazine where Pontiac is named car of the year they both say Pontiac went from the 58-60 X frame to the new perimeter frame for various reasons. Safety in side collisions, lowering the body between the frame rails to lower the car for better stability and deepening the floor foot well area and more economical to manufacture because the exhaust doesn't have to be run through the frame, a one piece drive shaft instead of a two piece with a center bearing and the frame is lighter and cheaper to manufacture. My 62 Catalina has much more room underneath the car than my 59 did. The exhaust is a breeze to put in compared to my 59 where the exhaust had to be bent and assembled in pieces through the holes in the frame.

D.

Oh yeah, X frame cars were a lot more trouble to work on but it was just accepted in an era when nearly all cars had them. I would think a 1958 Pontiac would be easier to work on than a 1948 one though?

[X-Frame]

Can we get back on track and see if we can come up with some, if not "the" last car to use a X frame type configuration?

And if we can identify that overturned special ops vehicle in "Spiderman 3" since I don't think any Humvees had an X brace?

Thanks!

[emjay]

Do you have any interest in retro-fits? Dad installed one in a 1915 Model T in the early 60's. He may have installed it earlier, but that's my first memory of it. No doubt about stiffening up that frame.

[Guest]

Can we get back on track and see if we can come up with some, if not "the" last car to use a X frame type configuration?

________________________________________________________________________

CERTAINLY! 1964 full size Chevy was the last to use a TRUE X frame.

D.

[X-Frame]

Can we get back on track and see if we can come up with some, if not "the" last car to use a X frame type configuration?

________________________________________________________________________

CERTAINLY! 1964 full size Chevy was the last to use a TRUE X frame.

D.

The frame you are referring to was still used on Buick Riviera until 1970. All other GM cars had abandoned it by 1965. But there were other cars that had "X type" frames past that such as the Checker Marathon until 1982.

Looking for even later if there are some?

[X-Frame]

Do you have any interest in retro-fits? Dad installed one in a 1915 Model T in the early 60's. He may have installed it earlier, but that's my first memory of it. No doubt about stiffening up that frame.

There are a lot of retro fits and even stiffners for unibody convertibles but only looking for factory made cars.

[Guest Jim_Edwards]

Even these early Fords you speak of will fall into a variance of the X in our book. Though they look like two bows linked in the center rather than straight line X, they still fall within the peremiters of the catagory. Ford started using this in 1933. The 1932 Ford had a ladder frame. Not sure what you are referring to as a K frame in 1932... example please If anyone has SAE info to post, please do.

Below is an example of the 1933 Ford frame out of a crazy 3-D brochure they made then but you can see they say it is a X type frame. I double checked and the 1932 is a ladder frame.

Another rare example of an X that I am sure would be disputed sat under the Totota Crown models of the early 1960s. It was massive and looks more like a H but it does bow towards the middle and Toyota calls it a X Frame.

Eric

You would be correct about being "disputed." Any frame with side rails is not an "X" frame. A basically ladder frame strengthened by having an "X" or "K" component is still a ladder frame regardless of advertisements touting the strengthening component as being an "X" frame. Marketing hype is one thing, engineering fact another.

[X-Frame]

You would be correct about being "disputed." Any frame with side rails is not an "X" frame. A basically ladder frame strengthened by having an "X" or "K" component is still a ladder frame regardless of advertisements touting the strengthening component as being an "X" frame. Marketing hype is one thing, engineering fact another.

I guess it doesn't matter what the car manufacturers or the frame production facilities calls them, it is only "your" opinion that counts?

Here is the Toyota frame just in case.. does it count even though Toyota calls it an X frame?:

[West Peterson]

Eric is looking for information for research into a book he is writing about X-frames, X-type frames, etc. I would appreciate it if everyone would quit with the griping over semantics. I am called white, but my skin is not really white. Eric is researching frames that are called X-type frames, and/or X-frames. He's researching all of them.

[Guest Jim_Edwards]

Eric is looking for information for research into a book he is writing about X-frames, X-type frames, etc. I would appreciate it if everyone would quit with the griping over semantics. I am called white, but my skin is not really white. Eric is researching frames that are called X-type frames, and/or X-frames. He's researching all of them.

West, no one is being argumentative. The issue regardless of someone wanting to write a book on the subject is what is really an "X" frame from an engineering standpoint regardless of what advertising at times may have called a frame design. It's not a matter of what anyone's interpretation may now be it is what was/is engineering design fact. I'm suggesting no one is going to find an automotive engineer that will agree that bracing a ladder frame with an "X" component between the rails makes that frame an "X" frame most particularly when in comparison the the GM "X" frame of the 1950s and 1960s. If you can, go for it and let the rest of us know.

Edited January 20, 2012 by Jim_Edwards (see edit history)

[Dave@Moon]

Here come a few off the top of my head:

1982 Delorean:

[Dave@Moon]

Lotus Esprit through at least 1989:

(notice that the frame is really 1/2 an "X", with the rear half a capital "T" shape at the end of a center beam)

[X-Frame]

West, no one is being argumentative. The issue regardless of someone wanting to write a book on the subject is what is really an "X" frame from an engineering standpoint regardless of what advertising at times may have called a frame design. It's not a matter of what anyone's interpretation may now be it is what was/is engineering design fact. I'm suggesting no one is going to find an automotive engineer that will agree that bracing a ladder frame with an "X" component between the rails makes that frame an "X" frame most particularly when in comparison the the GM "X" frame of the 1950s and 1960s. If you can, go for it and let the rest of us know.

Nope, I love a good sincere debate but hate to argue. It gets no one anywhere.

If I point you to some patent information which "designers" aka "engineers" state these as X-Frames or X-Type frames, would that help?

The bottom line is that this is a book about ALL kinds of X frames. Saying that a 1955 Oldsmobile has a Ladder Frame is incorrect. Saying it is a Perimeter Frame with X-Brace would be closer to the truth. Omitting the fact, as some authors have in books, that a car's frame has a x brace has caused some confusion in itself since a Ladder Frame by itself has a different meaning.

[X-Frame]

Here come a few off the top of my head:

1982 Delorean:

These high profile long X frames are called "Backbone" X frames. The Lotus also has the same kind as does some other foreign cars.