Top harness mountings.

Doug Clark · 02-02-08, 12:42 AM

Hi All,

I'm thinking about how to mount the top harness eye-bolts. In common with GT40's I've got an engine immediately behind the roll bar and don't want straps going into the engine area as that seems a recipe for disaster.

I'm also trying to achieve a flat face at the back of the roll frame to make it easier to mount the fire wall.

What you can see in the picture is the 44.5mm x 2.5mm DOM main loop and all the other tubes are 38mm x 2.5 DOM.

The intention is to put top-hat bosses into the horizontal tube and bolt up the eye bolt through that.

On the downside this leaves the threads taking all the applied load in a prang, which I'm not sure is a good idea?

Does anyone have any experience of doing something similar or other recommendations instead? Would this sort of arrangement be FIA sanctioned (I ask that as they seem to have the highest standards)?

Doug Clark · 02-02-08, 08:45 AM

I posted this question on another forum, some replies got me thinking and now the design is as below...

Anyone got a good reason not to do it this way?

Ryan L · 02-03-08, 12:10 AM

Doug

give Klipan/Autoliv in Melbourne a call, they make FIA certified 4,5 & 6 point harnesses. They also de tests of seats and other components in relation to FIA specs if you need certification. They should be able to give you a recommended practice for mounting the belt.

my preference would be to wrap it directly around the tube as its lighter and keeps the forces more in line, however this is just a personal view.

Could you make the bar diameter smaller, but thicker walled, that way it would be spaced of the firewall enough to get the belt through?

Noticed it on the locost forum but not oz cubbies – maybe some one there would have better info regards rego and local motor sport requirements.

Regards Ryan

Doug Clark · 02-03-08, 08:35 AM

Hi Ryan, good ideas, I'll investigate the legality of looping over a tube for road use here in WA.

Russ Noble · 02-03-08, 02:24 PM

Quote:

Originally Posted by Doug68

Hi All,

The intention is to put top-hat bosses into the horizontal tube and bolt up the eye bolt through that.

On the downside this leaves the threads taking all the applied load in a prang, which I'm not sure is a good idea?

I wouldn't worry about that Doug, you're bound to have a lot more thread engaged than you would have with just a nut on the back.

I'm sure you'll die from internal injuries caused by the belts long before the threads pull out of either system

Keep up the great work.

Cheers

Kalun D · 02-03-08, 03:08 PM

You may have already done so but locate your optimum hardware first, then design around that. The best is 7/16" AN eyebolts, but the standard availability is limited on the length.