sub frames in the pan-based cars

still trying to differentiate the mechanical underpinnings of the pan cars from the tube cars. What in particular is the steel sub frame that has reportedly put to rest the tube vs. pan strength debates of the past . Will an average guy feel the difference when he sits in each to test drive them; especially if it is not a side by side comparison? -Peter

I'd say no. I have a tube-framed Beck, which I like very much, but I've also driver Gordon Nichols' pan-based CMC with subframe, and I can't tell any difference in solidity. Both were more solid than some factory-produced convertibles I've driven in recent years.

I think the most noticable difference is that the tube framed cars seem to have more room for your feet. The pan based cars tend to not have much room to the left of the clutch pedel.

I think the twisting referenced on pan based cars was to those without the substantial steel perimeter sub-frame. IMHO the CMC fram is way over built --- I could see where relying on just the VW pan center tunnel would result in some real body twisting (as the floor pan itself doesn't give much strength). The subframe also gives facility to have heat in front of vehicle.

I have owned a VS and presently own a Beck. The Beck is signifcantly more solid than the VS, but I am not sure what that means. They both go around the corners like any typical rear engine car of the period. When I look under the Beck as compared to the VS, (which by the way, has a steel frame in the mold, I think) the Beck just looks more solidly built. Particulary the way the engine and transaxle is mated to the frame. Lot's of solid metal work in that area. The front end is not as open as the VS, meaning I can't use my tow bar because the underbody takes up too much room. The good side of that is that I can easily get a spare tire and lots of tools in that compartment. I think there may be less storage in area of the fuel tank. There is way more room in the engine compartment, but I think there may be less room in the back seat. There is definitely more room inside the vehicle. Anyway, you didn't ask for all this but maybe it will come in handy.

I'd suggest that not all tube frame cars are the same. Jack up an Intermeccanica under the side of the car, and both tires will come off the ground, and the doors will still open and close. It all makes for a car that will survive all that you can throw at it, for as long as you own the car.

I'm not saying other cars with tube frames can't do that. I don't know. I'm just saying it's a nice thing to have a car that you know is solid, and will stay solid.

I have a 1969 VW pan-based CMC, with the body sub-frame integral to the body (glassed in, in other words).

I can jack it up under the middle of the door, both wheels on that side off the ground, and the door opens and closes normally, as it always does. I also cannot see a difference in the door seams when sitting level or jacked up.

I guess my pan based car is solid too....and will probably stay that way. I suspect a lot of pan-based cars on here are about the same.

What I HAVE noticed is that many tube-frame Speedsters seem to have a bit more leg or hip room in the cockpit....

gn

You know.....I looked at my last post and thought, "Gee....that sounds a little cheeky.....What if I sound like I'm full of BS? Maybe I should back that up with some evidence".

This is especially apropo, since I've been hearing this myth for years (Decades, if you count the people who've built some Dune Buggies on tube frames) and I didn't believe it then, and I still don't. The fact of the matter is that lots of people have heard this myth and believe it without hard evidence to the contrary - not their fault, they just need to see something positive to change their thinking.

Sooooo........

I went out to the garage, took a picture of the rear-most door seam, then carefully placed a jack such that it was slightly to the rear of the center of the door width and right on the outer edge of the pan. Here's the original seam:

http://i49.photobucket.com/albums/f254/speedster356/DSC02596-1.jpg

It appears to be "bowed" in the middle, but that is just an optical illusion created by the flash lighting into the depth of the door opening. You'll see the same thing a couple of photos down in the "After" shot, but it's NOT there when I sight downward along the seam. Read on>>>>>

THEN I jacked up the passenger side til the wheels were both off the ground (I had a bit more room over there - you guys with semi-grown kids who've "inherited" most of their "stuff" and have it all in YOUR garage will understand) and took another picture of the car up on the jack, just to show the setup (remembering my college physics lab setup notebooks).

http://i49.photobucket.com/albums/f254/speedster356/DSC02597.jpg

Once that was done, I took another picture of the same door gap. I didn't bother to get out a scale to measure them, but, to my eye they are exactly the same. If anyone wants to prove it to themselves, they're welcome to come on over and I'll re-inact the setup and YOU can measure them with a scale to see that they're the same.

The door gap while jacked up:

http://i49.photobucket.com/albums/f254/speedster356/DSC02598.jpg

Lastly, I did another shot showing a bit more of the jack beneath the car AND the "Jacked Up Gap", just so there isn't any confusion. Note that the "bowing" is gone in this shot from a different angle:

http://i49.photobucket.com/albums/f254/speedster356/DSC02599.jpg

I certainly hope that this dispels some of the myth surrounding the so-called "weakness" of Pan Based Speedsters - at least the later CMC ones like mine. I can't vouch for many others (although I helped Mark Hall with his 1984 IM kit and THAT body had a sub-frame, too), but would be more than happy to perform this test on others, just for the hell of it.

BTW: I DID open and close the door a few times while I was messing around with the setup. It operated as if it were still sitting on the ground as normal - just didn't think to take a picture of it, but without an MPG, what good would a still do??

And don't get me started on how a pan-based car doesn't handle. Tell that to the two Cobra guys in the Beaufort Classic Car Club who've tried (and failed) to catch me through the back twisties of Roebling Road race course near Savannah.....

Gordon
"Puttin' my pictures where my mouth is"

Gordon----well said. My pan based car is super solid and corners like it was on rails. The doors open smoothly when jacked in any way
and the car feels like a "one piece" unit---very stable and solid.


The 2X4 welded steel peimeter contributes to the solidness and the stabilizer bar in front and the camber compensator in back take care of the ride.

Your racing story pretty tells the story---the proof is in the winning.----Jack

I'll chime in too. I usually jack up both wheels on each side under the original Beetle jacking points. The doors open and close while it's up without a problem. The car has been on th eroad for 15 years and the pan/chassis always seems solid to me.

I'll agree with that last remark. During my drives of the Hoopty, the thing that struck me the most is how it felt like one solid block of iron - one very fast solid block of iron.

I had a stocker CMC when I started my rebuild. I now have a mutt, but the CMC subframe that surrounded the pans is largely what was used as a backbone. I firmly believe that I could hack the tunnel out of my car from front cockpit to the rear firewall and the car would remain inflexible. Even before the heavy modifications, that framing provided solid lift points all around the car.

Like Gordon, I've put the car on the track. I'm going to go out on a limb and say that subframe provided me with the basis for the most rigidly consturcted Speedster on Earth.

Cory brings up a good point, often made in the past by some Dune Buggie folks:

While the central tunnel on a Pan-based Beetle sedan provides some degree of strength/support (mostly front-to-back in the middle of the car), contrary to popular belief it was the heater tubes along the sides that provided body/chassis rigidity and strength. While those tubes looked relatively simple, they were a remarkable design for the strength they provided, AND they were just simple stamped and welded sheets, made into BOTH a heater tube to get heat from the back to the front (OK, so there wasn't a whole lot of heat available in the FIRST place, but whatever was produced got delivered to the front with minimal loss) as well as THE main structural members of the car.

When the body is removed from the pan, the pan is remarkably wobbly until the Speedster or Dune Buggy body (or whatever else with a sub-frame) is placed on it to provide the stiffening needed via the body's sub-frame.

Some dune buggy bodies (I think the "Hum-Bug" and that ridiculous thing that looked like the Munster mobile) didn't have speedster-like sub-frames and the resulting "car" was almost dangerous to drive, it was so unstable.

At the extreme other end of the spectrum are the Military "Dune Buggies" produced by (I think) Chenowth. A couple of my Beaufort neighbors have used them in the past and their comments on frame rigidity go something like: "They are remarkable - stiff enough to take the pounding we give 'em (most have 40-60 Cal. gattling guns or missile launchers mounted amidships) and flexible enough to not break anything 50-100+ miles from base, running the desert at 80 - 100 mph." The machines my friends drive use Type 4 engines, have NO cooling problems out in the 120+ degree desert and go like stink. I wonder if Jake builds their engines??

Besides that, they've found that a softer frame lasts longer, as a stiffer frame tends to break, rather than "give". Take a look at Wikipedia's nonsense on them here> (although the reality is a lot different than what Wikipedia knows about):
http://www.rustrepair.com/app2/onlinecat.htm?r=ms&p=sm

Anyway, I hope someone appreciates this (limited) insight into how early Beetles were designed. NU-Beetles are "Unibody" cars. What that means is that the chassis and the body are a "single, welded unit". That's pretty much what you got when you bolted an early Beetle body onto the pan/chassis. The design was such that welding (an expensive fastening method in those days) was unnecessary.

Oh....and they didn't leak, either...

Bwaaaa Haaaaaa Haaaaaaaa!!

Wow, I've been away a few days and just read these posts. Thank you for the thoughtful and documented (Gordon Nichols) answers. This is surely very helpful in decicion making for a builder. I am planning on selling my current convertible which sags just horribly when put on jackstands. (1982 ALFA spyder). Look forward to the day I can run in a speedster.

I know of people who have jacked up the Jensen-Healy sports car and put creases in the rear fender.

I jack up Fern on the rear and I get 3 WHEELS off the ground. Yes 3. It lifts the whole car. So for some reason I think this jackin' BS is just marketing hoopla!

Ya think?

"I jack up Fern in the rear" Who is fern?

Hey Vince: Jack this!!

This is Fern... "Fern the Speedster" you jolly joker!

Hey, Mike!

What's the latest on the knee??

You become Bionic Mike yet?

gn

...he's BETTER, FASTER, STRONGER.....

Recall jacking up a blue rusty 914, lowered the rear on 2 jack stands and it broke in two....but not as hilarious as raising a VW bus with a shop lift only to watch the entire interior go up inside the bus as the wheels remained on the shop floor!