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Legal height adjustment for Harnesses that sit too low


imissedtheapex

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Hi all, just had my cage done and the harness bar is too low to give me the "10 degrees up from horizontal" mounting point that gives these things the optimum spine protection. Are there any legal ways to modify the cage or harness bar to get the mounting point higher or am I just going to have to drop the seat? For reference, here's how they sit. Single harness bar across the main hoop.

 

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Hi all, just had my cage done and the harness bar is too low to give me the "10 degrees up from horizontal" mounting point that gives these things the optimum spine protection. Are there any legal ways to modify the cage or harness bar to get the mounting point higher or am I just going to have to drop the seat? For reference, here's how they sit. Single harness bar across the main hoop.

 

I'm not sure what type of harness you have - brand plus 5,6,7 pt etc. I've got a Schroth 6pt Profi harness for use with Hans, and Schroth has harness info at https://www.schrothracing.com/sdocs/2009_Competition_Instructions.pdf. Page 12-13 has some shoulder belt info, and it mentions running the shoulder belts horizontally or downward at up to 20 degrees max. I'm not sure if any of that applies to your harness and cage, but it may be helpful in addition to whatever specific info you can find for your harness. - Jim

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+1 for the Schroth instructions. They are the most comprehensive set of instructions I have been able to find.

 

IMO, you should mount the seat as low as possible while maintaining good visibility in order to get your helmet down away from the cage.

 

How are your harnesses mounted to the cage? Mine are mounted with the typical bolt-on style of harness tabs that came with the harnesses, with 1/2" grade 8 bolts going vertically through sleeves in the harness bar. I only needed to add 1/2" tall shims under the tabs to raise them up for the proper angle. You can barely see 5 sleeves here; sleeves 1, 3, and 5 are for the seat back bracket, while 2 and 4 are for the shoulder harnesses.

 

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For a wraparound installation, there isn't a lot that you can do for height adjustment, other than add another bar just above your current one, although that might be a little too high. Wrapping the harnesses so they come off the bottom of the higher bar (like the wrong way to hang a roll of toilet paper) might help a little, although the harness will still be mostly in line with the bar centerline when it is cinched.

 

Or, you might be able to add something like this, and attach the shoulder harnesses to it (rather than the second set of HANS harnesses). Contact HMS for exact details about using (or not using) this for primary shoulder harness attachment. You would probably want to use a 1" OD sleeve around that ~3/8" bolt where you would wrap the harness.

 

https://www.hmsmotorsport.com/products/double-shoulder-mounting-bracket

 

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In any case, make sure that your harnesses have a straight shot from your shoulders to their attachment points without being redirected up, down, or sideways by the holes in the seat. Be sure that you are testing the fitment in full race gear with your HANS device in place.

 

Mark

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Also, don't be afraid to find a way to brace that FIA-approved seat back to the cage. While the FIA says that the seat and brackets can resist various forces in a crash, a factory 18 or 20 gauge floorpan likely will not. I have seen some of these newer seats come with threaded bosses already molded into the seat back for easy attachment.

 

Mark

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thanks for the responses guys. I think I'll be ok actually looking back at the CCR and the Schroth install directions. If not, I'll get the HMS piece.

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