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Roll Hoop
Posted: Tue Aug 04, 2009 7:18 pm
by Rich
Has anyone modified or replaced the roll bar in their convertible for something else?
Re: Roll Hoop
Posted: Tue Aug 04, 2009 8:26 pm
by Hans Efde
I know 2 cars.
First one is the red conv now owned by johnyfixit, it has a race approved roll over bar that sits over the head of the driver and has extra struts.
The second one is the yellow lhd conv on my website. It is owned by German Josef Zabel who removed the whole roll over bar!
Here is a link to his car on his website:
http://www.saab-zabel.de/fileadmin/bild ... das100.jpg
Re: Roll Hoop
Posted: Tue Aug 04, 2009 8:59 pm
by Rich
Thanks Hans,
I noticed a distinct twist to the shell when I jacked up the drivers side front wheel (the unsecured roof wouldn't sit flat) and I was wondering if anyone had cross-braced the bar to add a bit of torsional stiffness.
Rich

Re: Roll Hoop
Posted: Tue Aug 04, 2009 9:05 pm
by Hans Efde
My convertible is surprising stiff. I can't see it twisting. I do notice the scuttle shake and windscreen shiver, but that's it. I have a GTM convertible with the sandwich floor. Also as mentioned by Alistair considerable thick layup that causes problems finding the correct seals! Do you know what you have? Does your car have a sandwich floor?
Re: Roll Hoop
Posted: Tue Aug 04, 2009 9:10 pm
by Rich
Hans Efde wrote:My convertible is surprising stiff. I can't see it twisting. I do notice the scuttle shake and windscreen shiver, but that's it. I have a GTM convertible with the sandwich floor. Also as mentioned by Alistair considerable thick layup that causes problems finding the correct seals! Do you know what you have? Does your car have a sandwich floor?
Mine's a GTM too and I believe it does have a sandwich floor, it certainly felt like it when I drilled through it the other day.
Rich
Re: Roll Hoop
Posted: Tue Aug 04, 2009 10:29 pm
by Alan D.
Hi Rich,
Already thought about this, my GTM convertible has the sandwich floor. I've got rid of all the other rattles and bangs, except the windscreen frame banging against the top of the door. I've devised a fix in conjunction with Victor. I've mocked up some plastic pipes, that go from the roll cage to the screen header, fixing underneath the header rail, using the hood/hardtop fixings. It can be done,but I need to make them up in steel pipe. But the job is in the queue, as I'm trying various engines (now on the third different type of engine) in a MK2 at the moment. But interestingly the last show we (The N.E. group) went to was a Mini show, Mini Mania, anyway I got talking to a Triumph Stag owner and he was telling me that when the Stag was first road tested, it had horrendous scuttle shake and they fixed it with that front to back brace covered in leather, that solved the problem. I originally thought about doing a front cage mounted to the floor,then picking up the door hinges etc., then attaching to the rear roll cage. As usual with me over engineered. I think now just a front to back stiffener will do,Alla Stag. Have a look at the Marlin 5exi, which is were my none original (as usual) idea was stolen from!So the idea is a straight tube with 90degree bends at each end ( sort of straightened C shape) ]=[ (like this, I've done it with the bracket symbols on the computer.) But with two short spacer pipe between the two front to back pipes, in order to keep the 90 degree legs short, in order to keep the structure stiff. Sort of Viagra for a convertible!
Alan D.
Re: Roll Hoop
Posted: Tue Aug 04, 2009 11:14 pm
by Hans Efde
Alan, I've glued a bit of foam rubber strip on the windscreen frame where the top of the door hits. That solved that rattle.
Re: Roll Hoop
Posted: Tue Aug 04, 2009 11:21 pm
by Alan D.
Thanks Hans,
I've already tried that, I have two seals as mentioned elsewhere. But I guess your car is stiffer than mine. But it is much better with the coilover rear suspension as opposed to Hydro-gas. More progressive travel with springs I think! I've not put the car on the road this year, so it is sitting a garage, feeling unloved!
But I will get around to it soon I hope!
Regards Alan
Re: Roll Hoop
Posted: Thu Aug 13, 2009 9:58 am
by Rich
I'd wondered about a T bar type of arrangement, on mine it would really have to curve to follow the roofline or I'd be forever belting my head on it. I guess a Carbon moulding would do the job.
Rich
Re: Roll Hoop
Posted: Thu Aug 13, 2009 8:05 pm
by Geoff Butcher
Isn't there a chance of putting stresses into the windscreen/frame which they might not like? All the loads have to go somewhere...