What rollbar shape do I go for? I want a road car (MAC#1 ZR), not intended for track use, but don't want to rule out the odd track day. I guess it's a compromise between, safety, weight, cost and looks. In the end it's personal preference, but just thought I'd get some opinions on here. I have 2 options:

Basic rectangle
+ve's cheaper, lighter, More room in boot?
-ve's Less safe??

Rectangle with back braces?
+ve's Safer?? Stronger, would back braces help if you were hit in the rear?
-ve's could interferre with hinged boot lid, weight, cost

Backbraces are essential, a hoop without braces would just bend flat under the weight of the car dragging along bthe road. Braces would also add strength to the rear in the event of a rear end shunt.
Regds
Ian

back braces every time, with a cross brace if you want to be really safe. additional weight of back brace isn't much.

An unbraced single loop will fold up or break off in an accident making it about useless and just extra weight and cost over no bar.

i may be bias but i quite like the luego velocity roll bar. its got quite a nice shape and pretty good bracing for strength.

http://www.luegosportscars.com/cars/velocity/pics/archive/pages/velocity5_jpg.htm

http://www.luegosportscars.com/cars/velocity/pics/archive/pages/velocity19_jpg.htm

quote:

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Originally posted by roadboy
Backbraces are essential, a hoop without braces would just bend flat under the weight of the car dragging along bthe road. Braces would also add strength to the rear in the event of a rear end shunt.
Regds
Ian

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Keep the back braces to the sides and there is still room for a hinged boot lid. There is on mine.

Rear braces should be a minimum. I'm having a diagonal too. Dunno why people with a single hoop bother to be honest - in all but the most delicate of rolls it'll fold up and they'll still get smeared up the road.

I've got mine tapered in at the sides about 10 degrees and slanted forwards a-la Caterham which i think looks good. Can see it in my photo archive.

Liam

hmmmm, unanimous opinions, can't realy argue with that. Looks like I'll go for the back braces on safety grounds. I like Smart51's idea so you can still have a hinged boot lid.
Thanks!

Also, two things I see often are roll bars that are too short, and no knee bars.

The rollbar needs to be 2" above a helmeted head for SCCA rules for a reason. With no helmet you don't need to crush your head, just bang it on the concrete at speed and you're done.

The knee bar also helps reduce that chance by changing the angle of impact. For example in the velocity pics that were posted you have to draw a line from the top of roll bar to the very front of the car (unless there is a hidden kneebar). This is the angle the car will land/slide and your poor head has to be below that line. Adding a kneebar under the scuttle/cowl makes that line further up and gives more head room.

Maybe Im just a little cautious though. I snap rolled my truck into a ditch a while back and put the roof into the seat
.
http://www3.telus.net/public/corym/crash/s1.jpg

Cheers.