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X-Frame

X-Frame History - help

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You got to remember that the old high profile cars of the 1940s was now outdated and with each new year the manufacturers tried to lower and lower the car's height.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

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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.

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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?

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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!

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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.

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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?

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

D.

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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?

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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.

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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.

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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?:

post-68778-143138808207_thumb.jpg

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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.

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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 by Jim_Edwards (see edit history)

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Lotus Esprit through at least 1989:

sport350frame1s.JPG

(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)

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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.

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Here come a few off the top of my head:

1982 Delorean:

frame.jpg

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

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When I think of Lotus I think of this Elan 1500 chassis... which is an X but a bit disproportionate. Just another "variation".

post-68778-143138808511_thumb.jpg

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So do all the racing applications fit in ? "X"s are used through out most racing chassis and are used extensively to provide additional torsional rigidity.

post-48905-143138808514_thumb.jpg

Maserati Birdcage chassis

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1976 Lotus Europa (very similar to the Esprit):

b4frm1.jpg

These I would definitely NOT call an X in any variation.

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So do all the racing applications fit in ? "X"s are used through out most racing chassis and are used extensively to provide additional torsional rigidity.

[ATTACH]114983[/ATTACH]

Maserati Birdcage chassis

Nice try, jumbled mess though on this one for sure. Racing applications will be mentioned but not in detail since they are not "factory built" cars. Older Ferrari, Maserati, Alfa Romeo etc... which could be purchased off a showroom floor that have factory built tubular or similar frames in X configurations will be.

As for DeLorean... they were built 1981-1982 and the Checker was still being built in 1982 as well. Any later than this?

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The Triumph Spitfire used a X type chassis until the end in 1980. Other Triumph cars may have used an X in later years, worth a look.

spitfire_chassis_940_1.jpg&w=940&h=600&zc=1

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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.

_________________________________________________________________________

I concede the Buick:eek:---I never would have thought GM would have done that knowing the safety issues:confused:, and the DeLorean and the Lotus. The Toyota and the Triumph are not joined at the hip.

D.

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There is one car I haven't verified yet and maybe someone can tell me for sure or have a picture of this? That is of the last built 2-seater Ford Thunderbirds from 2002-2005. I have seen a CAD picture of the underside body of one and it shows a X brace but wonder if it went into production that way? This was to be a retro car in many ways but the uses of an X like in the original 1955-1957 T-Birds is one I need to verify still. Thanks!

There is also another variation from the 2000's that we will mention but I don't dare say here because they are ones that is stretching it a bit but still a variation just the same.

Edited by X-Frame (see edit history)

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I concede the Buick:eek:---I never would have thought GM would have done that knowing the safety issues:confused:, and the DeLorean and the Lotus. The Toyota and the Triumph are not joined at the hip.

D.

They don't have to be joined at the hip... that is why we call them "variations" and we will categorize the different styles.

Believe me, I have even had a few rounds with my co-author on the project when it comes to what to and not to include depending on interpretation. I have a certain criteria and he has another but we have come to compromise and will list those we don't agree on as mentions in the book even if we call some "embyronic" or "evolutional".

And it is these puzzles like the Riviera having the x frame through 1970 we need to approach and clarify. Just like "why" did Buick drop the x braced frame in 1959-1960 for a K style, then go back to a X style in 1961?

Edited by X-Frame (see edit history)

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