The Speedster top Frame - Low Bow 2 High bow

[JTR70]

This thread is to discuss and share all aspects and details of the 356 Speedster top frame from its introduction in 1954 to productions end in 1958. My interest and obsession on this subject began 13 years ago as my quest to acquire and original set of "low bows" for my "coupster" project was getting underway. What I have learned in a nutshell is the actual "true" low bow top frame was a very low production version unit and was phased out in very early 1955. Its total production constitutes roughly 450 total units give or take. This would mean that the first 200 1954 speedsters all were fitted with them and only about 250 of the first 1955 speedsters which followed. Couple this low production number with alot of these frames being switched for high bows or just plain missing a top frame all together and you have very rare bird!
Here is some of the info that has led me to this conclusion.


This photo is taken directly out of Brett Johnsons Porsche authenticity book. He was right on the money in describing the top frames. I learned this lesson the hardway after 8 disappointing purchases of this second gen. frame all claiming to be low bow frames from a pre-a or an early 356A. Once we measured them they ALL came out about the same. I learned Once the linkage configuration changed it became a "high bow" frame. There were some evolutionary changes; small back window(pre-A&AT1)to big back window(T2) but the center bow was raised up when this second configuration came out.(= "higher bow") Again this happened in early 1955.


Here was the second bit of confirmation also taken from Brett Johnsons book. This is an illustration taken directly from the 1955 parts catalog. It clearly depicts the second generation speedster top frame version. The original "low bow" frame was gone quite early.


A more recent discovery closely pin pointing the low bow's exit from production is 1955 speedster chassis 80469. It is pictured above and retains its factory original "high bow" version top frame. So by at least the 269th '55 speedster the factory was no longer installing the low bow. More later. Thanks for reading this! Justin

[JTR70]

There was a thread post by Chuck House that was started back in '09 on the Registry talk concerning this very subject. According to the late Richard Miller who had vast amounts of direct experience with these old frames the original "low bow" version was gone by the first 100 or so 1955 speedsters. This is far fewer units than I had earlier eluded to however my guestimate was based purely on what I directly know. So to boil it down according to Richard Miller there were 200 low bow frames installed for 1954 and ONLY about 100 or so 1955. Approximately only 300 +or- low bow frames in total. Far fewer than I was thinking. if you like to read this thread here is the link: http://porsche356registry.org/356talk/1/11070.html
Up next will be a detailed spotters guide for low and high bows. Thanks for reading this! Justin

[JTR70]

Before I move onto the ID part of the frames I wanted to revisit the significance at least in my mind what a "high Bow" configuration in the 1955 parts catalog means concerning just how few of these first gen. tops were made. I have to assume that the '55 catalog was being written and published sometime in late 1954; but exactly when? Only one guy came to mind who could posses an answer and that's Charlie White. I wanted to say thank you once again to Charlie for taking the time to answer my questions. I had several:
1) When were the changes set for the following new model year? Answer: it varied from July on up through September of the current year.

2) When would the catalogs be published? Answer: publishing could begin as early as the end of August and as late as middle December.
3) Was there a First generation Low bow frame depicted in the 1954 parts catalog? Answer: There was not a 1954 part catalog published that year. The 1953 catalog I guess was sufficient to cover 1954.
The next catalog was 1955 and we only see a high bow frame. This means the first gen. top was never officially listed in a Porsche catalog!
The dates mean that the second generation frame was developed and probably into production as early as September 1954. I can only speculate that factory had a hundred or so first gen tops to use up in early '55 before the second verson was fitted. Hope this make sense. Thanks for reading this! And thank you Charlie White! Justin

[JTR70]

Speedster top frame spotters guide.

When I first began this journey for a low bow top I was hard pressed to recognize these subtle differences in the two basic frames. Now however I can pick one off at a glance. Here's what to look for:

Here is a direct side by side comparison of the two frames. The 1st generation lowbow top is on the bottom (tan repaint)and the second and final frame configuration high bow is on the top.

To the untrained eye they are dangerously close and quite similar. The first obvious change was to the rivets. Early lowbows used a solid steel rivet and the later second version frames went to a hallow brass rivet. Infact on closer inspection these "brass rivets" were not really rivets to begin with but are just sections of brass tubing that were flare punched at both ends.
The second subtle difference is to the configuration of this foward connective linkage. Note how the lowbows upper link swoops over the main center joint and "leapfrogs" over creating the "lock" or stop for the frame. The high bow by contrast is just a straight shot and configures more of a strong "V" shape. The little "Half-moon" at the bottom of the center joint beacme the new "lock" or stop for the high bow.

Here is a detailed shot of the new Lock/stop for the high bow. This "tooth" became my first tell tale sign when I was figuring all this out. "if it has this feature, its a high bow". More details ups next. Thanks for reading this! Justin

[JTR70]

One of that last and most easy difference to indentify between this two frames is at the rear bow's lower mount.

A first gen. low bow will have this dog leg kick at the end of the rear bow. The fulcrum tab it works off of is pitched at a lower angle.


By contrast the second version's rear bow has no kick at the bottom and its fulcrum tab is set at a much steeper angle to probably eliminate the need for the previous bend to the tips. The tab is also a bit longer than a lowbows tab.

As stated in the begining the original Lowbow frame was phased out quickly however it did go through a few evolutionary changes during it s very short lived run. Will share those in detail next. Thanks for reading this! Justin

[JTR70]

The first 44 speedster top frames

Pictured above is the "Holy Grail" of Speedster top frames and is probably the rarest production convertible top frame that Porsche produced. This top has the initial leather strap latching assembly. This along with several other small unique details make it different from the later 250 or so 1st gen, lowbow frames that were to follow. This one truely is the rarest of the rare. More to come. Thanks for stopping by! Justin

[roy mawbey]

Justin,

That has been very interesting reading. For more years than I care to remember I haven been confused by 'high' and 'low' bow frames. I really found out nothing on this till I see you super description by photos.

In fact I have always thought the hood height was the only difference but possibly I am wrong on that. Is the low bow lower or nearer your actual head when sitting in the car. They always look low even on late speedsters.

Also, am I am sad to say, I thought possibly the windscreen height might have been modified as well. You see, so much to know and how easily it is to spend money like you did on buying wrong frames.

I wonder what one this speedster had?

Roy












Roy

[JTR70]

Thank you Roy! Alot of it I learned the hard way after many disappointing purchases through the years. Yes, the low bow is closer to your head. The factory must have gotten tons of feedback concerning lack of headroom in '54 so they set out quickly to correct it. The windshield frame remained the same all through the production run. The real secret to the change in height was not that the bows are inches longer on a high bow because they aren't the difference in overall length might be 1/2 to 3/4 of an inch on the center bow between these two frames. The gain in height was mainly achieved by shoving the center bow backward and "standing it up" at steeper angle creating a "higher bow". The first gen Lowbow lays more forward creating the "lower bow" I hope that made sense. The '55 in your article is pictured with a High bow. The position of the rear bow in the restored shot makes me think it might even be a later T2 "big window" version.

Here's a T2 frame. See how the rear corner of the back bow really protrudes outward. A first gen or a small window second gen. is not as pronounced and gives a softer line. The last pic of that '55 shows the top contour indenticle.

Here is a Lowbow for comparison; takes on more of a flatter even squarish feel compared to a high bow. They look quite similar but when you see them together side by side on a car the high looks like a pup-tent compared to the low. I had a photo of that but for the life of me I can't find it.

Here is an old factory photo of a brand spanking new 356AT1 speedster(A style rockers) Note the Lowbow style "small" back window with softer and lower rear bow that is above it. Now look at that "high"and defined center bow; much higher than a first gen. but still retains the early characteristics behind this taller center bow. This is the second version 1955/56 interum top frame that causes the "lowbow" confusion. The frame remained identicle but the rear bow got taller and the back window bigger for the T2. Justin

Thanks again Roy!

[JTR70]

One of the very first Speedster top frames.

It was Rusty Tubs who eventually came through on an early Low bow frame after almost a decade on the hunt. When offered this frame I did not hesitate; I knew how rare they were anyway but a super early version like this one certainly would never come my way again. I stepped up big but it was well worth it to me! Still in its original grey paint but what is most interesting was the lack of a chassis number being punched in it. During this early phase all top frames were fitted and stamped to a chassis. After taking delivery I contacted Don Zingg an early speedster expert to get his opinion. Below is our corrospondence and Don's response to my initial email for some help:
Hi Justin,

Were you wondering whether that frame is appropriate for the particular
Speedster you're restoring (sorry, I've forgotten which chassis number) or
just curious about the application in general?

If the frame is a genuine Version I design, then it is unusual not to find a
serial number stamped somewhere on the driver's or the passenger side - -
either on the side link over the door, on the bolt boss where the top is
attaced to the cowl behind the door, normally in both places.

If you have a digi-camera, email a couple photos and I can better advise - -

In any event, the familiar toggle latch replaced the leather strap set up
around Speedster 80044.

Don




Photos that were sent to Don.



Don's response:Justin,

That top came from one of the first 50 Speedsters - - and not having any
serial number makes me think it could have come from one of the first dozen
chassis. If you clean off the front bow you should discover several pieces
of sheet metal are welded together to form the compound curves.

Do you have any history for that top frame?? Onto which car are you
planning to use it?? OR, are you thinking about selling it?? (I know a
couple owners hunting for that style top frame).

Don
Here are the weld details in the header bow that Don told me to look for in that last response

Gas weld that runs along the middle joining the left and right sides together.

Second weld runs the entire spine of this bow making it comprised of four seperate pieces. Actually its two layers of sheet metal that comprise this header so its really 8 seperate pieces all together. A good amount of time and effort went into making just this unit. It would shortly be stamped out of one sheet though still layered twice. This change would happen before the very short 300 or so unit run. More details to come. Thanks for reading this! Justin

[roy mawbey]

How interesting Justin. I am amazed Don knew so much about the frame. I think if the frame looks as good as this its a shame rusty tubs didn't find the car in a similar condition? Maybe they obtained it separatly from the car?

I can believe it wasn't cheap, and actually even more valuable these days. A good buy Justin

Roy

[JTR70]

Thanks Roy! Yes, I never regretted buying this top frame. This purchase is also allowing me share alot of detials I otherwise would have never known. Don of course is a well spring of information concerning these early speedsters; my thanks to him again! Concerning this top frames original car; what I have learned through the years is as rare and as uncommon as these Type 1 frames are it is quite common for the vehicle itself to be missing its original frame. This usually happened either to a swtich to a high bow for better clearance which was done often in the early days from what I've been told or just removed to go racing or cruising then simply forgotten about. As a matter of fact here is a list I have put together over the years of early '54/55 cars that have been seperated from thier original frames:
speedster: 80011, 80013, 80054, 80124, 80180, 80225, 80236, 80244*, 80266* (* Top frames I have)
These are just the ones I personally know about, I'm sure their are many more. You can begin to see Roy alot of M.I.A. low bow top frames.
Thanks again! Justin

[JTR70]

My next mission was to make this early unique latch assembly complete and functional again. To do this I would need the leather strap dimensions and the other half of this latch; the female reciever which mounts onto the windshield frame. A very tall order to locate a pair of those being only about 44 pairs were made.

I had this photo of one from my old excellence magazine from '88 when they did a story on Speedster #5. However there was no way I could have an accurate copy made from just this photo. I knew I'd have to find an original to copy from.

[JTR70]

After some asking around it was my good friend the late Ed Smith in Eukia Ca. that came through for me. During this time he was restoring speedster #14 and graciously offered to help by sending me one of the original recievers from this car to make a pair of copies from. Will always be grateful to him; Rest in peace my friend. Here are some comparison shots:

Original #14 on top and a new copy below.

Original on top again, middle one is how I picked them up in very basic rough form from the machine shop. I spent several hours carefully filing and shaping to get all the contours and corners correct. Then more time still hand sanding the file marks out and finally polishing the brass. Bottom one is in finished form and ready for chrome plate.

Having an original example to directly copy from was so crucial. The approach angle of the reciever slot had to be right on in relation to its base and its ultimate mount attitude once on the Windshield frame. Original one is on the left.

Original on the left. I was pleased. Though It was 600.00 in machine shop time this was my only shot, I had no choice.

I now had the other half to make these latches work again.

[JTR70]

Now for the fun and exciting part of mounting them to see how it was all going to fit together. Fortunately the speedster windshield frame remained unchanged all through its production run so it was only a matter of tapping a couple of new holes into my WS. frame.

Pictured here fully mounted with correct chrome spade screw. I found that coupe rear quarter hinge screws were the perfect length and head size.

They fit like a glove. The lip on the mounting face hooked right under the edge of the Windshield frame just like it was supposed to.

Now with the top frame for a test fit. Could not have been better The approach angle on the reciever hole was right on and everything slipped into place. This was a great day!

I quickly mocked it up with a strap from some leather I had laying around. I now needed to find out the exact dimensions of the original and how it was actually used. Another email to Don Zingg was in order. Up next. Thanks for stopping by! Justin

[JTR70]

Contacted Don Zingg about the leather strap details here was his response:
Hi Justin,

Yup, all is well here - - hope that's the same story at your end.

The original "top latch" straps were 14mm wide, not more than 2mm thick, and approx.* 170-200mm in length. In all my travels I have yet to find an INTACT original strap, and so the length measurement is a guesstimation. The strap must be long enough* to manipulate into the tab slot, roll it over and back up thru the tab slot - - but not too long as to hang down into the driver's field of vision (that's a laugh!).

The thickness of the original leather strap is reminiscent of the thin leather used on the OEM luggage straps for the early 356A cars.

Hope that helps.

Don


Approximately 200mm in length? At first I thought that was way too long; and it certainly would hang down in the field of vision especially the way I had it just lopped through once! However once I figured out his "double back" sinch it made perfect sense.


Even though I never saw this latch engaged before this mock up just did not seem correct and it certainly wasn't secure just passing through the eye under no tension.

After I got my head around Don's description I cut a new leather strap, this time longer. Pulled the leather back through and it sinched down just like it was supposed to.

This is how the design works and made perfect sense at that moment. My thanks again to Don Zingg for sharing his knowledge with me! I may of just left it hanging loose incorrectly like these guys:


I got in contact with Tony Singer next to have him make me up some straps based on Don's dimensions. Up next. Thanks for reading this! Justin