Roadster roll bars

[flyerncle]

I knew that was coming !!!!!!!!!!

[georgenewman1]

i noticed that the roll bar didnt attatch to much, as a result i made the rear hoops of the body support out of 20mm x 3mm seamless tube and braced it down to the diff cage to add extra stiffness

[mark]

Im using a fibreglass rear end from saturn and this is where i anchored my rear roll bar stays, they are bolted in from underneath with m14 bolts through 6mm support plates plates.

Before anyone says it yes i did put one on the other side aswell

[georgenewman1]

how gooder fit are these rear ends. i have a prefabbed aly tank that sits about 1" in from were the skin would sit, willl this contact with the pannel??

[mark]

Unfortunately you need to modify the rear end a little to make them fit and a book spec fuel tank wouldnt work.

But a few simple mods gets them fitting perfect and they really look the part.

[flyerncle]

Andy is about somewhere and will read this,wouldn't it be sensible to make the rear support tubes to match the rear Saturn/Triton tub,this would make the rear end more structrually sound once again as per the book and offer a little rear end protection also for the fuel tank,can someone enlighten me as to why it was removed other than to fit the Fabby tub.

[HandyAndy]

Originally Posted by flyerncle

Andy is about somewhere and will read this,wouldn't it be sensible to make the rear support tubes to match the rear Saturn/Triton tub,this would make the rear end more structrually sound once again as per the book and offer a little rear end protection also for the fuel tank,can someone enlighten me as to why it was removed other than to fit the Fabby tub.

i may be wrong but the original rear tub tubes were there to support an ali rear tub which isn,t needed for a GRP tub, personally i think that the way Mark has done his rear brace bars offers a stronger anchorage/triangulated point for the roll bar strength.
Then again there is nothing to stop a builder adding some additional 25mm box tubes to create a fuel tank protection cage which could possibly be attached to the diff cage.

andy
ps, in my opinion of course

[flyerncle]

I forgot about the mods for the tub

[mark]

Anyone who has built the rear end to book spec with the round tubes and then chopped it off to fit grp (like i have) will probably agree that the design i have used is a much more sturdy alternative, that coupled with the fact that my rear stays are of a larger diameter and thickness than the book spec should be more than strong enough.

I am in the process of making my tank at the moment and once that is in i may consider some extra protection in that area but im trying not to over engineer things too much as i dont wanna end up at 700kgs on the weighbridge

[adrianreeve]

Mark

I did exactly the same as you, and my stays go to the same place. Looks good, and after a bit of stress analysis (I used to be a 'proper' engineer) turns out to be a fair bit stronger than original, as stresses are dissipated over a greater area.

Cheers

Adrian