Belts

[Louis]

Belts and their mounting in the vehicle are probably one of the most important parts of the car.

So: with the introduction of HANS I've put a bar in my cage behind the seat which feeds the belt to the top of the drivers shoulders at just above horizontal, well within the 10 degrees. The belts then go to the floor mounts on the rear seat box / tank saddle. These are at more than 45 degrees maybe 60 or 70 degrees. The scruteneer at Anglesey asked me to move them by passing the bar, and mounting straight to the floor. I reluctantly agreed but wasn't all that happy about the belts going direct to the seat.

The point of the post: the drawing in the blue book shows the 45 degrees to the seat, but I guess this applies to the bar too? What's the mathmatical reason for it being 45 degrees? There must be one other wise it wouldn't be recommended? Secondly I've unfortunately crash tested those belt mountings and I'm happy to say they worked.

I think unless I mount the belts to the bar, which I think I will (though it places a lot of faith in my welding!) I will struggle to meet the 45 degrees. I could mount them to the rear chassis legs but that seems entirely stupid. Maybe others in the club will also have this issue so it there a broadly applicable recommendation available anywhere. Is the bar the safest place to mount from?

[naughtybear]

Mine have been on a bar behind the seat all season and not had any trouble , a scrut at brands commented that is how it should be done with hans

[nick nice toes]

Mine like ash's are fastened directly to the bar behind the seat using the original clips with the tails neatly rolled up and tied.
Raced like this all season and asked various scrutineers to check they were correct and always been told that they are correct.

[Caryl Wills]

There are very specific instructions for fitting belts with a Hans device which you can find here: https://www.schrothracing.com/sdocs/2009_Competition_Instructions.pdf. It is amazing what happens to the shoulder straps in a frontal impact at just 31mph.

The jist of these instructions are that shoulder straps should be mounted on the cage cross member (not on the floor) and the angle should be between horizontal and 20 degrees down (not up) from the driver's shoulder bone. The distance between the shoulder straps mounting point is crucial and there is a table on page 13 and 14 in the instructions that describes how they should be fitted.

If you want to wrap the shoulder straps around the cross member, Schroth make a special buckle designed for that purpose.

I'll try and post a picture of the cross member and fittings I made for Nick's car (52) tomorrow.

[Sean]

buckle the belts to the tube  none of your shonky welding to worry about  :P

(But glad to see the scrutineers thinking about driver safety )

[Caryl Wills]

Sorry this took a while, but here are some photos of the cage harness bar we use in our team. Ideally the bar should be less than 400mm behind the centre line of the drivers shoulders (see https://www.schrothracing.com/sdocs/2009_Competition_Instructions.pdf page 13 and 14). We have a steel band wrapped around the harness bar that a pair of standard seat belt eyebolts are attached to. This allows you to get the angle of the shoulder straps within the 0 to -20 degrees range by either mounting the eyebolts from the top or from underneath. The steel bands are welded to the harness bar to ensure they can't rotate or slide from side to side.

From the photos, it looks like the harness bar is a bit high, but when I'm sat in the car the belts are right at the top of the seat apertures and my belts run just under horizontal (about -1 degree). In cars 52 and 92, we put the harness bar in a bit lower so it is more suitable for different height drivers. The shoulder strap angle stays in the 0 to -20 degree range for all drivers in the team.

[Trevor Williams]

Just seen these two photos, and I really hope that you understand that this post is purely about your compliance with the regulations and therefore your safety.

The fitment of the harness as shown in these photos is completely illegal, and will result in your car failing scrutineering!! The ONLY methods for attaching harnesses to a harness bar are described in the blue book

These do not comply....

[Simon Crook]

Hi Trevor as I have to change my belts this coming season, looking at Caryl pictures is the problem that the bar that the belts are attached too, looks to high? or the way its attached to the bar is the issue?

[Trevor Williams]

Simon
The bar itself is ok, it is the use of the fabricated bracket that then has the bolts attached to it for the belts to clip to. This does not comply with the regs, specifically K1.3.9 which states that if you are mounting the belts to a harness bar, the two ways that this can be achieved are by wrapping the belts around the bar, or by using the inserts as described in Section K Drawing 44

Cheers
Trevor

[Simon Crook]

Thanks Trevor