Book spec roll bar

[DaveyB]

If I need to increase the height of the roll bar using the book spec can I add what ever amount extra I need say 100mm.would I need to adjust the 80 degree angle to it still aligns to the width of the chassis?
I anyone gets my drift.
Thanks.

Daveyb.

[ayjay]

If you kept the angle at 80 deg then the top rail would have to be shorter and would probably look odd and out of proportion. It looks like you may have to play around with mock ups til you get an angle that looks ok.

[Richard Dryden]

You could either bring the usuall 80 degree angle slightly closer to 90 to obtain the correct width or, you could shorten the length of the top of the roll bar so that at 80 degrees you would still obtain the correct width. Hope this helps.

[Talonmotorsport]

If you end up remaking your roll bar might I suggest you have it made like this:

[DaveyB]

please excuse me sounding thick are you saying from the 80 degree angles turn in 10 degrees, or just straight down for the extra from the 80 degrees ? just looking at your web site how close are you away from producing roll bars/ roll cage, is this something you may be able to produce in the future?

Thanks for the response all very helpful as usual
Cheers

Daveyb

[Talonmotorsport]

It depends on what size tubing you want the roll bar made from? I can currently do them in 42x2.5mm ERW which is more than strong enough considering what the chassis is made of and before some one says oh but the MSA - FIA blue book says this... I'm not making them for the 750 motor club race cars just road IVA passable cars.
I used to make NASA autograss specials from 32x2.5 ERW class 8,9,10 and they smack telegraph poles at 70mph+ and the whole chassis is made from it. The NASA rule book says that the roof of the chassis must 50mm from the top of the drivers helmet that is how strong the tubing is.

This link is what 32x2.5mm tubing copes with so 42x2.5mm is not going to be much different.

http://flickrhivemind.net/Tags/class8,crash/Interesting

[Shorty]

I'm currently looking for a roll bar if anyone can help.
Grp rear so I'm not sure on the length of the rear supports.

I sent you a pm Phil if you can help

[voucht]

Originally Posted by DaveyB

If I need to increase the height of the roll bar using the book spec can I add what ever amount extra I need say 100mm.would I need to adjust the 80 degree angle to it still aligns to the width of the chassis?
I anyone gets my drift.
Thanks.

Daveyb.

Strange, I had to post this twice. Hope this one will work.

Anyways... here you have your answer: 8.2° instead of 10° from the vertical axis.

RollbarDaveyB.jpg

Black lines on the drawings are the middle axis of the main hoop.

Hope this will help

[DaveyB]

Thanks, and sorry if you have had to post this before but it's very useful, and thank you, talonmotorsport when I work out what I need in terms of extra height I will PM you about possibly making a roll bar up.
Sorry to keep going on about it, is there a minimum distance your head should be from the top of the roll bar.

Daveyb.

[voucht]

Originally Posted by DaveyB

Thanks, and sorry if you have had to post this before

Not you fault Davey, no problem, I just posted it a first time yesterday, and checked one or two hours later, and the post was not there any more.
May be a collateral victim of the spammers hunt