Interesting Seatbelt read

[J.C.]

http://www.opentracking.com/5_pts_vs_6_pts.htm

[AcidGord]

Speaking of belts I read on Honda-Tech that the SCCA (And possibly NASA) is adopting a _2 year_ expiry on harnesses in 2004? (Apparently due to insurance pressure)

Thats going to sting some budgets.

[James Mewett]

The referenced article (opinion) is wrong with respect to 5-point and 6-point harnesses.

In a 5-point harness the sub belt's function is to keep the lap belt in place while it is being pulled up by the shoulder harness tension loads. It is not intended to restrain one by one's crotch. It should be approximately vertical to serve this function, because before it become effective it must align with the pull of the shoulder harnesses. If it wraps under the body it is useless. A 5-point harness is appropriate for the upright seating position of the cars we drive.

A 5-point harness will not work properly with an extremely reclined seating position. Imagine the extreme case of a fully reclined position. In this case the lap belt and shoulder harness serve no function but to hold the body down. The occupant will slide out from under the lap belt. In this case a 6-point harness acts like a parachute harness and it restrains the occupant by the pelvis. For a 6-point harness to function it must wrap under the legs and not straight down.

A 6-point harness is unlikely to be the best choice for anything other than formula cars. In a street car the upright seating position renders a 6-point harness no more effective than a 4-point harness.

[Marsh]

Originally posted by James Mewett
The referenced article (opinion) is wrong with respect to 5-point and 6-point harnesses.

In a 5-point harness the sub belt's function is to keep the lap belt in place while it is being pulled up by the shoulder harness tension loads. It is not intended to restrain one by one's crotch. It should be approximately vertical to serve this function, because before it become effective it must align with the pull of the shoulder harnesses. If it wraps under the body it is useless. A 5-point harness is appropriate for the upright seating position of the cars we drive.

A 5-point harness will not work properly with an extremely reclined seating position. Imagine the extreme case of a fully reclined position. In this case the lap belt and shoulder harness serve no function but to hold the body down. The occupant will slide out from under the lap belt. In this case a 6-point harness acts like a parachute harness and it restrains the occupant by the pelvis. For a 6-point harness to function it must wrap under the legs and not straight down.

A 6-point harness is unlikely to be the best choice for anything other than formula cars. In a street car the upright seating position renders a 6-point harness no more effective than a 4-point harness.

Your absolutely right. I can't believe that was missed in the article. I just thought it was common knowledge.

[Nissan Racer]

Originally posted by James Mewett
The referenced article (opinion) is wrong with respect to 5-point and 6-point harnesses.

In a 5-point harness the sub belt's function is to keep the lap belt in place while it is being pulled up by the shoulder harness tension loads. It is not intended to restrain one by one's crotch.
Oh man, I sure hope not!

[Marsh]

In a 5-point harness the sub belt's function... It is not intended to restrain one by one's crotch.
Originally posted by Nissan Racer
Oh man, I sure hope not!

Actually I've driven a car where taking your feet off the rest made for some severe discomfort. Ooooo, I get sore just thinking about it. :(