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Post by Midlana1 » 21 Jan 2011, 19:41

For now this is going in the General Build sub-forum because the seat belts need to have proper mounts installed during assembly. I'll add more information over time.


Over and over, I see builders wondering how to install their belts correctly. Once upon a time that was a fair question, but in these days of the Interweb, there's no excuse for even asking. I can't help but get a little bugged, wondering, "Why don't they check the manufacturer's website?" Virtually every belt manufacturer has graphical instructions, so why not take their word for it instead of faceless advice off a forum? Note how the height of the shoulder straps is specified, which will depend upon your build and seat lay-back angle. It will dictate the height of the main rollhoop cross tube.

Here are some direct links to installation instructions from various manufacturers. I put Schroth first due to their very extensive instructions; I highly recommend reading through their documentation regardless which brand you actually buy.

Schroth ... ctions.pdf
Simpson ... positions/
Gforce ... positions/

Impact Racing... (was charged with issuing fake SFI stickers on some products, including belts.)

Seat Mounting
From the 2011 SCCA Rule Book:
The driver’s seat shall be a one-piece bucket-type seat and shall be
securely mounted. The back of the seat shall be firmly attached to the
main roll hoop, or its cross bracing, so as to provide aft and lateral support.
Seats homologated to and mounted in accordance with FIA standard
8855-1999, or FIA.Standard.8862-2009 or higher need not have
the seat back attached to the roll structure. Seats with a back not attached
to the main roll hoop or its cross bracing may not be mounted to
the stock runners unless they are the FIA homologated seats specified in
an FIA homologated race car. The homologation labels must be visible.
Seat supports shall be of the type listed on FIA technical list No.12 or
No. 40 (lateral, bottom, etc). Passenger seat back–if a folding seat, it
shall be securely bolted or strapped in place.
Mounting structures for racing seats may attach to the floor, cage
and or center tunnel. Seat mounting points forward of the main hoop,
between the center line of the car and the driver’s side door bar and
rearward of the front edge of the seat bottom are not considered cage
attachment points in classes with limitations on the number of attachments.
A system of head rest to prevent whiplash and rebound, and also to prevent
the driver’s head from striking the underside of the main hoop shall
be installed on all vehicles. Racing seats with integral headrests satisfy
this requirement.
The head rest on non-integral seats shall have a minimum area of 36
square inches and be padded with a minimum of one inch thick padding.
It is strongly recommended that padding meet SFI spec 45.2 or FIA
Sports Car Head Rest Material. The head rest shall be capable of withstanding
a force of two-hundred (200) lbs. in a rearward direction. The
head rest support shall be such that it continues rearward or upward
from the top edge in a way that the driver’s helmet can not hook over
the pad.
HANS stands for Head And Neck Support. At one time, there was only one company selling the device and (I think) they called themselves HANS. But, like "Kleenex", several companies now make head and neck restraints:
The "R3" unit ... es/r3.html
Hybrid Pro Rage ... -rage.html


Driver's suit

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Re: Safety

Post by bgkast » 23 Apr 2013, 06:55

How close is the cage to the average driver's head when all strapped in? Do you think there is a danger street driving the car with no helmet?

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Re: Safety

Post by Midlana1 » 23 Apr 2013, 08:21

I'm 6'-0" and the top of my head is 2" below the bottom of the roll cage tubes. The SCCA rules state that the driver's (helmeted, I assume) head should be 1" below the top of the roll cage, so I'm good there. However, I reclined my seat quite a bit and some builders will no doubt prefer a more upright seating position, and that'll eat into the headroom.

Your post reminds me that I need to install SFI 45.1 roll-cage foam. Note that this is NOT the soft stuff sold in most off-road stores. The proper (and therefore expensive, ~$10/ft) padding is quite hard, designed to stop one's head from getting injured by flying frame tubes.

To answer your question directly, yes the cage may be a safety concern on the street. A frontal impact will be handled by the belts and a rear impact will be handled by the headrest. An impact from the right side will be okay due to all the crush space, compared to getting hit from the left side, which I don't even want to think about. The cage becomes a concern in a roll-over situation, where the driver ends up being a rag doll, possibly floating up out of the seat with his head getting close to the cage. All this aside though, once you drive the car you'll realize that you're a bug compared to everyone else, with the car being so low that they'll likely ride up over the top of you. Worst case would be sitting at a light behind an SUV, and seeing someone not paying attention coming up behind you. Midlana wouldn't get pushed into the car ahead, it'll likely get pushed under it... more stuff I don't want to think about.

The key is to consider your car invisible to other drivers, and to never pace them in their blind spot. Think of the car like a four-wheeled motorcycle and you'll be fine... probably.

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