I'm feeling guilty about pestering Gene with questions so I thought that I would throw this out for the collective wisdom of Rally Anarchy. I have read through article 253 about a hundred times now! It looks like the FIA gives us three options in regards to harness mounting:

1. Use the stock rear belt attachment points.

2. Use a 1.5 X .095 harness bar, attached to the body shell as close as possible to the center line of the rear wheels.

3. Use a harness bar between the rear stays.

In all situations the belts must be between 10 and 45 degrees below the back rim of the seat.

There is no mention of attaching the belts to the main hoop. I assume that I cannot do this. I would love to attach a bar to the main hoop that kicks back a few inches (and is braced accordingly).

What have you guys put in your cars?

And one more thing........When measuring a Taco gusset does the FIA count the distance of the legs with or without the cut out in the point of the angle?

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

I'm not sure how you would attach a harness to the main hoop?? Please clarify your confusion


Gussets...there is a range of suggested measurement. Without looking it up about 4 to 6 inches on the spine, don't really worry about the cutout for fitting. This doesn't really seem to apply to door bar gussets however. On many cars the shallow angle of the X would require the whole thing to be plated to get enough distance on the taco spine.

I was thinking about it and it seems putting the guessits top and bottom on a door bar x would be better. They would end up nice and small and would do more to keep the x from coming apart in the middle under unthinkable circumstances.

Sorry Gene. I was trying to say a harness bar that bisects the X in the main hoop.

I was hoping to be able to transport four tires in the back seat area for TSDs. If I install a harness bar between the stays or the shock towers I loose this space.

A harness bar in the same plane as the main hoop X would be better but there may not be enough space between the back of the seat and the X. A harness bar that is attached to the main hoop but offset 2 or 3 inches rearward would be ideal. A guy can always dream right?

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

For the harness bar, if it is allowed, I know some of the cages have had JUST the harness bar bent back behind the main hoop. I'll post a pic in a second.

The HANS recommends the mounting in the main hoop. If you run the belts all the way back, they recommend crossing the belts so they dont slip off the shoulder areas.

"For the harness bar, if it is allowed," That is what I'm asking!

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

This is way easy not that I see what you don't...

We actually don't require belts to be mounted per FIA regs. FIA only mentioned for cage design and seats (NRS not RA).

However this copied from the 253 : - If installation on the series anchorage points is impossible for the
shoulder and/or crotch straps, new anchorage points must be
installed on the shell or the chassis, as near as possible to the
centre-line of the rear wheels for the shoulder straps.
The shoulder straps may also be fixed to the safety cage or to a
reinforcement bar by means of a loop, and may also be fixed to the
top anchorage points of the rear belts, or be fixed or leaning on a
transverse reinforcement welded between the backstays of the
cage (see Drawing 253-66

Second sentence says 'straps may be fixed to the cage or a reinforcement bar by means of a loop.' That reinforcement bar can be the transverse bar in the X. It doesn't say you must mount them on a transverse bars in the rear backstays.

Kids....

You can ask us, but the final word will be a RA/NASA/CARS inspection.

For RA/NASA since they don't go by the book with FIA rules (I'm pleading ignorance for CARS rules since I haven't read the book) you don't NEED to follow FIA. It does help to use them as a guideline though.

For my two cents, I've got a harness bar in my main hoop. You need to make sure you still have that belt angle down, and make sure that you have enough harness length so the buckles aren't interfering with shoulder placement or going through the seat.

It's a bit trickier to get the belt angles right since you're working with such a short belt length. Not so bad as the driver might or might not change much, but the co-driver height might change a bit.

Edit:

http://www.youtube.com/user/Danglydotcodotuk#p/u/0/MAIuieC49oE prodive used a main hoop harness bar on the new mini. 1:14 into this video.



Edited 1 time(s). Last edit at 03/27/2011 06:00PM by BillyElliot.

Well, after talking to the guy that made my belts years ago I like to mount the shoulder straps at the main hoop. The reason is you will get a certain amount of stretch in a crash. I forget what the figure was but he said you get a certain amount of stretch for a given length of strap. So mounting the shoulder straps all the way back on the rear deck like I had in my Opel way back when is a bad idea because your head could easily hit the steering wheel if you run into a tree even if the belts are done up tight.

Quote
Doivi Clarkinen
Well, after talking to the guy that made my belts years ago I like to mount the shoulder straps at the main hoop. The reason is you will get a certain amount of stretch in a crash. I forget what the figure was but he said you get a certain amount of stretch for a given length of strap. So mounting the shoulder straps all the way back on the rear deck like I had in my Opel way back when is a bad idea because your head could easily hit the steering wheel if you run into a tree even if the belts are done up tight.

That was the other reason HANS recommends the belts be about 6-8 inches behind you, if I'm remembering correctly.

When my cage was finished, I had the harness bar between the rear shock towers. At the log book inspection with Gene, he told me that was legal, but he prefers the bar close to the seats, end he will bust my balls at tech every time until I add it. We added 2 bars in the rear X behind the seats.

Nice thing about that location is you can put the co-drivers bar lower so you can lower the seat and still have correct angles.

As a NASA tech, I have no issue with 2nd bar bowed bacok behind the plane of the main hoop, as Dazed_Driver shows it. Gene, any issues from your end with that? I doubt that RA would have any issues either, but I can't speak for them. We did just this to get the shoulder strap angles right versus the original cross bar, made the shoulder strap angles sharply down.

The mention of an angle of -10 to -45 degrees below the top of the seat (harness holes), is a problem at the -45 end. US convention for a long time has been to keep that around -10, as the thinking is that -45 can crush the spine.

And Dave Ckark, the long rear harness length (like to the old rear package shelf attachment) has been a Euro type thinking that has persisted, maybe even now. The idea behind that was that the belt stretch would reduce peak shock on the body. But, in the US, the short-strap thinking you recite took hold maybe 15 years back, so short harness lengths are the way in the US.

One thing in setting the vertical position of the harness bar is to look at how the belts go through the harness holes in the back of the seats. You might want to set a bit steeper strap angle if you are tall and the harness straps hit up against the top of the harness hole when seated normally. Tall folks have a real issue whereby there is no way to have the harness straps go through the holes in the back of the seat, and straight to the sholder. It almost seems that seat should have some vertical adjustment for the hole locations. Some seat backs do have higher harness holes than others......

Mark B.

Random question, how are those cases held in, Sean? Just bolted to the floor through the case?

The curved bar in the main hoop is OK with RA rules. The only thing is too make sure the belts can't slide around the bend and become out of alignment. I would also be ok with wleding a couple plates on the back of the main hoop and a bar between those or tubes from the main hoop to the 1/2 laterals and a bar between those. Lots of ways to do it.

Long belt vs short belt....I see both sides of the story. I did read many years ago that the human body can stretch many inches forward even when in belts. Longer belts may add to the amount you move forward. Long belts also take up the access to the rear floor. The most important reason for me is that short belts are available most everywhere. I've seen a couple teams miss events due to expired long belts and only short belt replacements available.

However...I really like the way Sean did his Merkur and the possibility of different height harness mounts.

"as near as possible to the centre-line of the rear wheels for the shoulder straps." So we just ignore this bit?

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.