Anyone with a JPS car have the "optional" tube chassis stiffening kit?

I thought all the makers went with a stiffened chassis that eliminated the need for additional stiffening. John Steele appears to be offering it as an option. Would this make his cars more trong/stiff than a Vintage Speedster. I visited the JPS shop yesterday and am making my plan (half the fun). Very nice attention to details on his cars,by the way.

HEY PETER DID U SEE MY COUPE
WERE MY DRUM SKINS ON YET

Peter,
The tube frame option will undoubtedly make the car more stiff than a pan base. Whether it justifies the additional cost is a matter of individual preferences.

The frame that JPS uses traces the exact pattern of the VW pan, so you don't gain any leg room as you do in the Intermeccanica, Beck, SAS, and Thunder Ranch speedsters.

The fiberglass bodies used by Vintage, JPS and later CMCs have a built-in tube frame which goes a long way in stiffening the pan-based cars. With the addition of front beam braces, front & rear stabilizer bars, door braces and truss bars, a pan-based car is pretty close to being as stiff as a tube framed car. JPS offers a kit to retrofit pan-based cars. I have done all the modifications to my car except the door braces.

The biggest problem I have with the tube-frame option is the legality. The frame removes the VW VIN#. No pan - no VIN. The way the car is registered is by grafting on the rear frame horns with a VW donor VIN. It is questionable in the state of California that our cars are registered legally, even when they have a valid VIN, based on the donor pan. It seems to me the tube frame option is a definite registration violation, unless you are going to register using an acquired SB-100 certificate.

Peter,
I think I remember this coming up before. There is a kit that is offered from Cip1 (I think) that does the same thing. It's two bars that bolt right up to the front beam and the frame head. I put one on my car a year or so ago. It was a nice upgrade for the minimal cost. I can't seem to locate the pics, but I also did a little more reinforcing this past winter (pic below) that was a HUGE improvement to the integrity of the car.

Gerd; Your car was there! I recognized it immediately as I drove in. Sorry,can't confirm the drum skins were on or not . We did refer to your car inconversation as it has the wide five wheels that I asked about having on a IRS rear end. I forget the answer from John regarding that. Oh,my son just loved your coupe.Told him to start saving--he's only 15...Tell me about the engine. Is that the 2332? who supplied the engine? Does John frown on have customer's going elsewhere for engines,or does he like to keep that under his control for natural reasons of added profitability,etc.?

Terry, I rode in a black/tan customer's car for a short loop around the block.The car has a 2332cc motor and felt very stiff(and quick) I will email John about this,I guess.Not sure that the car I rode in had the tube stiffener kit. It was the first ride I have had in any speedster so nothing to compare it to. One heck of a lot stiffer than my 1982 Alfa spider(!).Terry, I take it your car was not stiff enough as originally built?

Mickey, That bracing looks soooo intrusive to the doorway of your IM.Looks almost radical,like a racing setup. Looks like you're having fun though.

Peter,
It was plenty stiff and quite acceptable as is. Certainly stiff enough to use for moderate driving.
But I wanted exceptional handling as I live in the country and the winding roads here seduce you to drive balls out.
The suspension upgrades, along with the improved engine and Berg 5 speed have made my little Penny a strong performer.

FWIW: my understanding is that there are three variations on this theme: pure pan based, where the FG shell (w/ some light steel cast within it) is fixed to a shortened VW pan (one gets the VW VIN w/ this); the pure tube frame or purpose-built chassis, of which there would be many variations within the industry (you will have a new car, unrelated to a VW w/ this option; or what I call the hybrid tube frame, wherein only the aft portion of the VW is used to hold the engine and tranny, i.e. the "fork", plus a just a bit of the aft portion of the VW pan, which inlcudes the part w/ the donor VW VIN. For this hybrid design, from about the back of the seats fwd, all is built-up from steel plate and square channel. This later is what JPS offers as his tube frame, and is what I have on my car. The addition of sway bars (two strengths available), the IRS suspension and you have a pretty rigid car that corners pretty flat. I will say this however: the car is not perfectly rigid, although I think it would be better than any pan based version. It does squeak now and then, indicating to me that stuff flexes and moves a little. The addition of a roll bar/frame would add a bunch to stiffness and also the door frame braces as pictured would add too. I do not have these, although the idea of the properly integrated roll bar and frame is very appealing for safety as well as stiffness. BTW: the all time winner in the stiff chassis competition is the Hoopty (Miss September in your SOC calendar, BTW), which is basically a purpose-built, custom space frame design that you could hoist up with a hook from any available corner and not hurt a thing.

Kelley, Belated thanks for your fwiw.I didn't know that JPS did a whole diiferent frame up front as you have on your car. If it squeaks a little it must be very minor as I have not heard too much criticism from speedster owners overall. I rode with J. Steele in one of his cars with the 2332 CC over the tracks near his shop this August. The car felt very solid. Suppose they loosen up with more miles.

LOL, try rubbing it, that's what Vince does to get it stiff.





Rub this Vince!