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My S&W rollbar and Racing Harness questions


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I'm having my S&W roll bar put in and we are trying to determine where the shoulder belt bar (gets welded to the main loop, goes straight across behind the seat). should be located vertically.

 

First, my long legs and seats required that the Corbeau A4 be 1/2" forward of the raised shelf behind the seat. So I had the guy section the main hoop and put it up on the shelf next to the inner wheel houses. It's also about 3/4" below the roof sheet metal, just in front of the "box" that holds the dome light just in front of the hatch. I'm having it tied to that box with plates welded to the hoop to accept bolts to go in the holes in that box.

 

Anyway, this all means that the seatbelt bar can't go where it's designed to, at the bend in the main hoop, if I want it to line up with the holes in the seat back for the harness.

 

The question is, where should this bar be vertically, directly at the mid height of the holes in the seat?

 

Also, the most room between the seat back and the seatbelt bar I could come up with is like 1/2". Is that O.K.?

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if you read rules for scca cages the shoulder harness has to go straight back.if harness goes down toward rear it compresses your spine in a crash.i have a thick tube with flat strap welded to the ends mounted to shoulder harness reel holes on rear strut towers.it braces the strut towers and gives a place to fasten shoulder harness.

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Guest Anonymous

Pete --

 

If the bar is only 1/2" behind the seat, you may have a problem with the hardware that is used to attach the belts to the bar - they may wind up about halfway through the slot in the back of your seat. This could lead to them hanging up as you tighten the belts, giving you a "false-tight" feeling that might be dangerous if you ever have a significant incident, not to mention being a PITA.

 

If you plan was to scallop the ends of the seat belt bar for a factory-clean finish at the main hoop, here's a option that worked for me, even though I didn't have the interference issue to deal with -- we cut the bar about 6" longer than the inside of the span, then heated and flattened the ends from that point out, about 3" each end. We then bent the bar into a hook shape so that the flattened ends are wrapped around the short legs that go down to the tops of the rear wheel wells (not sure you have these), then welded the hooks to those legs at shoulder height. This moves the belt bar back about an 3/4 the thickness of the bar (might just be enough) and IMO makes it less likely that the belt bar will pull itself away from whatever it's welded to if you have an impact that deforms the attachment point. We also welded in a short (4"?) "stand-off" bar that runs from the belt bar to the diagonal, where the two would intersect if they were on the same plane. If I hit something hard enough to bend the belt bar with the force from my shoulder belts, I may have larger issues looming, but since I carry students in the right seat on a regular basis, our combined weight/momentum might deflect the bar some in a heavy frontal impact.

 

You could also run your belts over the belt bar and attach them to the floor of the hatch area so that the hardware is aft of the bar.

 

One more thing - I use a fairly upright seat position. If your seat is laid back pretty far, mounting it to a more upright position might gain you some distance between the seat back and the bar. I prefer the upright seat position - easier to operate the wheel, IMO, but that's a personal choice.

 

Keep in mind that I am neither a safety expert or structural engineer, though I suspect that if I ever test my set-up to near the breaking point, I won't be posting on THIS bulletin board anymore.

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Guys, thanks for all the input. I sat in one of the seats and my shoulder is actually above the top of the hole in the back rest, maybe a half inch. So I told the guy to weld it in so that it's in the center of the cut out vertically. It'll probably angle up just a bit. It's probably all welded in by now icon_wink.gif. One thing I am ignorant on (among many) is the methods for attaching the belts.

 

It seems Summit Racing has belts with different attachment methods which may help.

 

Then again, I may hav to just weld a tab on the bar that has a bolt hole that's behind the bar a bit (gusseted, of course) to gain the clearance I need.

 

The seat is reclined a bit, but that's to make in comfortable with the seat in the position it is - a bit forward - and give me a comfortable reach to the steering wheel and shifter.

 

Thanks again!

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They have changed this since I was building my ITS car back in the mid 90s... Used to be a degree of acceptability below the horizontal plain. Interesting that they site compressing the spine... there must have been some data to provide enough feedback.. Good to know... Pete, scratch what I told you off line.

 

Mike icon_eek.gif

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The way I've done my belts is to screw i nmounts to th stock lap belts. These are big hooks really that the belt clips onto. For the shoulder's I've got belts that loop around the bar - no hooks or hardware that attach directly to the bar. I HAVE been told to avoid the Y belts as they can apparently have problems but I don't recall the exact issue with them. My belts are all individual but I've yet to mount the submarine belt. I went with Simpson through a local dealer - you MAY have trouble finding them in stock, I did (sigh). Can give you part numbers etc. if you want, turns out a local shop actually had what I wanted in stock - I was in shock!

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Guest Anonymous

Like BLKMGK, I used the stock lap belt mounting positions, with both stock and track belts bolted in. The stock belt can be a PITA sometimes with the track belt and hardware competing for space, but I like having both available. I also have the shoulder belts wrapped around the belt bar, then serpentined through the adjustment/lock-down buckle according to the very good instructions included by Racer Wholesale/Auto Pro. For the sub belt, I cut out a small section of the seat mounting frame and looped/locked it around that. Admittedly, this is sheet metal not rolled steel, but the function of the sub belt shouldn't have it carrying my full body weight at impact. If it does, maybe I want it to break away - otherwise life may not be worth living. icon_eek.gif

 

BTW, if you're getting harnesses, please get a roll cage or at least a roll bar - when you're cinched into place with 5 belts, you can't move much (a good thing), which also means you can't pull your head down or get it out of the way of a collapsing roof. icon_rolleyes.gif

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Aww, you're making me go out to the garage icon_smile.gif

 

Lap belt is listed as a Simpson 10-100. "Simpson Lap belt, Pull down, Red, Wrap". I'm having to use hooks to secure this to my stock mount points - no problem if you buy the hook kit, normally it's made to wrap over a tube.

 

Shoulders are listed as #33002 and is a 48inch wrap belt. This might be a bit long but they adjust pretty easily.

 

Don't have the sub belt handy to check or the hook and eye bolt numbers. Look through Summit or Jegs to find that stuff (shrug). Mine still aren't fully mounted due to other things taking precedence...

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Jim, thanks again. I'm forgoing the sub belt. The seats WON'T let me sub anyway as their pretty deep and have a good knee riser.

 

John, I have a rollbar with "frame supports" that go from under the belt bar on the main hoop down at an angle inward to the driveshaft tunnel. Also have bars that run from the top of the hoop to the strut towers.

 

Thanks again,

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Pete,

 

Im getting ready to start shopping for a rollbar... i was wondering if you have any pics of your SW rollbar you could post how its looks when delivered and when installed.

 

thanks

stony

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Stony, I have a picture of the parts laying on the floor after I unbundled them.

 

I believe some of the other suppliers (Allison?) also make roll bar kits that are maybe better than the S&W one. Some people don't like the fact that the S&W on is not seamless tubing, but that doesn't bother me.

 

I'll take pictures of the roll bar install once I get the car back out of paint jail and post them.

 

Cheers,

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Guest Anonymous

Just like some others, it's been a while since I installed SCCA-compliant belts, but I remember the rules stating certain seats that would allow the belt mount point to be lower than shoulder level, as these seats were tested and did not compress during testing... Although I believe these were all full-on race seats whose frames come above your head, and had the cutouts for the belts.. icon_confused.gif

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