Lotus Elan

Seat belt choice

PostPost by: frearther » Wed Nov 03, 2004 12:27 pm

>The only difference being you get less wet when it rains.< Well, maybe in
your car.....


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PostPost by: davidallen » Wed Nov 03, 2004 1:01 pm

This is a very interesting discussion on an area which I have spent no time,
(other than replacing the mounting plates because they had rusted away!)

Am I correct in believing the problem is in the event of a crash, some
designs hold your shoulders back in the seat and consequently, your body can
slide under the lower belt?

If this is so, what is the optimum design for a conventional 3 point belt? I
would take the approach of having the belt professionally modified (no, I
would not do it!) or moving the location of the mounting points. Are fixed
belts better?


David


-----Original Message-----
From: Evan C [mailto:***@***.***
Sent: 02 November 2004 18:51
To: lotus elan newsgroup
Subject: [LotusElan.net] RE: Seat belt choice



The only .and I repeat only..safe set up is the stock unit but not that
great.or a set of 6 points.with a crotch strap that you attach to the same
place as the lap anchors.and you actually SIT on the crotch belt.and it
attaches to buckle..

I have a set in my Seven.if you want pictures. I have 4 point in my
Elan..and I am always afraid of submarining under the belt.I am sure I
would..

Tony V

Tony,
This is not entirely correct. The belts in a 5 or 6 point harness cannot
eliminate the forces that produce submarining. The transfer of mass still
occurs- albeit to al lesser extent.
In the dynamics of a crash the most effective preventative measure for
submarining, not respective of belt configuration, is to increase the
incline of the seat pan.
Submarining is set in motion by an unimpeded horizontal sliding of the
drivers lower mass accompanied by the fixation of the upper body by the
shoulder belt(s). In order to prevent submarining the drivers mass must be
located top and bottom. This can be done by increasing degrees with a
3,4,5,or 6 point harness. It can also be accomplished by loading that mass
into a surface that will counteract its motion, or better yet a combination
of the two approaches. Additionally, a 5 or 6 point harness will locate
the driver with minimal excursion - BUT - the loads on the belts will be
significantly higher than if the harness is used in conjunction with an
inclined seat pan.

Been there - crash tested that. The dummy died of internal injuries.
Period.

Bottom line - these are old cars, and the belts they came with (while better
than nothing) are still 40 years behind the current understanding of crash
dynamics.
You have to do your own research and make your own decisions on safety.

Please drive safety, the world needs more Lotus fans...
-E
1969 FHC 8624






To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html



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PostPost by: john66s3 » Wed Nov 03, 2004 1:48 pm

David - The issue is that 4, 5 or 6 point belts where your shoulders are
both held back equally can cause you to submarine - particularly on the
"rebound". Correctly installed crotch belts will help, but they cannot be
properly installed with a stock Elan seat - you need a race seat where you
are literally sitting on the crotch belt. All you do with the belt wrapped
around the front of the stock seat is build up momentum before they get
tight - OUCH!. And who is going to religously put them on in a street car?
Three point belts are designed so your upper body twists, which keeps you
from submarining under the lap belt. The original Elan three point design
would have had to meet federal guidlines at the time. But, I would be very
worried about an aftermarket system that isn't set up to meet the
specifications called for by the unit. In particular, I would suspect that
the stock mounting points aren't correct for ANY aftermarket belt. I use
Schroth belts in my track car and went carefully through the proper mounting
process with the Schroth US supplier here in Boston. I have also seen many
videos from Schroth tests showing submarining with incorrect installations -
they are not very pretty. This is not something to "home engineer". If you
want to move away from the stock belts I strongly advise that you talk to a
knowledgable supplier, not someone who will just sell you some belts. Here
in Boston that would be HMS Motorsports.

John
66 Elan S3 DHC
88 BMW M3 Track Car

----- Original Message -----
From: "ALLEN, David" <***@***.***>
To: <***@***.***>
Sent: Wednesday, November 03, 2004 8:01 AM
Subject: RE: [LotusElan.net] RE: Seat belt choice



This is a very interesting discussion on an area which I have spent no time,
(other than replacing the mounting plates because they had rusted away!)

Am I correct in believing the problem is in the event of a crash, some
designs hold your shoulders back in the seat and consequently, your body can
slide under the lower belt?

If this is so, what is the optimum design for a conventional 3 point belt? I
would take the approach of having the belt professionally modified (no, I
would not do it!) or moving the location of the mounting points. Are fixed
belts better?


David


-----Original Message-----
From: Evan C [mailto:***@***.***
Sent: 02 November 2004 18:51
To: lotus elan newsgroup
Subject: [LotusElan.net] RE: Seat belt choice



The only .and I repeat only..safe set up is the stock unit but not that
great.or a set of 6 points.with a crotch strap that you attach to the same
place as the lap anchors.and you actually SIT on the crotch belt.and it
attaches to buckle..

I have a set in my Seven.if you want pictures. I have 4 point in my
Elan..and I am always afraid of submarining under the belt.I am sure I
would..

Tony V

Tony,
This is not entirely correct. The belts in a 5 or 6 point harness cannot
eliminate the forces that produce submarining. The transfer of mass still
occurs- albeit to al lesser extent.
In the dynamics of a crash the most effective preventative measure for
submarining, not respective of belt configuration, is to increase the
incline of the seat pan.
Submarining is set in motion by an unimpeded horizontal sliding of the
drivers lower mass accompanied by the fixation of the upper body by the
shoulder belt(s). In order to prevent submarining the drivers mass must be
located top and bottom. This can be done by increasing degrees with a
3,4,5,or 6 point harness. It can also be accomplished by loading that mass
into a surface that will counteract its motion, or better yet a combination
of the two approaches. Additionally, a 5 or 6 point harness will locate
the driver with minimal excursion - BUT - the loads on the belts will be
significantly higher than if the harness is used in conjunction with an
inclined seat pan.

Been there - crash tested that. The dummy died of internal injuries.
Period.

Bottom line - these are old cars, and the belts they came with (while better
than nothing) are still 40 years behind the current understanding of crash
dynamics.
You have to do your own research and make your own decisions on safety.

Please drive safety, the world needs more Lotus fans...
-E
1969 FHC 8624






To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links












To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links
John

66 S3 DHC
john66s3
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Posts: 10
Joined: 23 Sep 2003
Location: Harvard, MA

PostPost by: poiuyt » Wed Nov 03, 2004 7:38 pm

Where can I get replacements for the 3-point belts in my 1969 S4?

Thanks,

Steve B.


--- In ***@***.***, "John Oglesby" <[email protected]> wrote:
David - The issue is that 4, 5 or 6 point belts where your shoulders
are

both held back equally can cause you to submarine - particularly on
the

"rebound". Correctly installed crotch belts will help, but they
cannot be

properly installed with a stock Elan seat - you need a race seat
where you

are literally sitting on the crotch belt. All you do with the belt
wrapped

around the front of the stock seat is build up momentum before they
get

tight - OUCH!. And who is going to religously put them on in a
street car?

Three point belts are designed so your upper body twists, which
keeps you

from submarining under the lap belt. The original Elan three point
design

would have had to meet federal guidlines at the time. But, I would
be very

worried about an aftermarket system that isn't set up to meet the
specifications called for by the unit. In particular, I would
suspect that

the stock mounting points aren't correct for ANY aftermarket belt.
I use

Schroth belts in my track car and went carefully through the proper
mounting

process with the Schroth US supplier here in Boston. I have also
seen many

videos from Schroth tests showing submarining with incorrect
installations -

they are not very pretty. This is not something to "home engineer".
If you

want to move away from the stock belts I strongly advise that you
talk to a

knowledgable supplier, not someone who will just sell you some
belts. Here

in Boston that would be HMS Motorsports.

John
66 Elan S3 DHC
88 BMW M3 Track Car

----- Original Message -----
From: "ALLEN, David" <[email protected]>
To: <***@***.***>
Sent: Wednesday, November 03, 2004 8:01 AM
Subject: RE: [LotusElan.net] RE: Seat belt choice



This is a very interesting discussion on an area which I have spent
no time,

(other than replacing the mounting plates because they had rusted
away!)


Am I correct in believing the problem is in the event of a crash,
some

designs hold your shoulders back in the seat and consequently, your
body can

slide under the lower belt?

If this is so, what is the optimum design for a conventional 3 point
belt? I

would take the approach of having the belt professionally modified
(no, I

would not do it!) or moving the location of the mounting points. Are
fixed

belts better?


David


-----Original Message-----
From: Evan C [mailto:[email protected]]
Sent: 02 November 2004 18:51
To: lotus elan newsgroup
Subject: [LotusElan.net] RE: Seat belt choice



The only .and I repeat only..safe set up is the stock unit but not
that

great.or a set of 6 points.with a crotch strap that you attach to
the same

place as the lap anchors.and you actually SIT on the crotch belt.and
it

attaches to buckle..

I have a set in my Seven.if you want pictures. I have 4 point in my
Elan..and I am always afraid of submarining under the belt.I am sure
I

would..

Tony V

Tony,
This is not entirely correct. The belts in a 5 or 6 point harness
cannot

eliminate the forces that produce submarining. The transfer of
mass still

occurs- albeit to al lesser extent.
In the dynamics of a crash the most effective preventative measure
for

submarining, not respective of belt configuration, is to increase
the

incline of the seat pan.
Submarining is set in motion by an unimpeded horizontal sliding of
the

drivers lower mass accompanied by the fixation of the upper body by
the

shoulder belt(s). In order to prevent submarining the drivers mass
must be

located top and bottom. This can be done by increasing degrees
with a

3,4,5,or 6 point harness. It can also be accomplished by loading
that mass

into a surface that will counteract its motion, or better yet a
combination

of the two approaches. Additionally, a 5 or 6 point harness will
locate

the driver with minimal excursion - BUT - the loads on the belts
will be

significantly higher than if the harness is used in conjunction with
an

inclined seat pan.

Been there - crash tested that. The dummy died of internal
injuries.

Period.

Bottom line - these are old cars, and the belts they came with
(while better

than nothing) are still 40 years behind the current understanding of
crash

dynamics.
You have to do your own research and make your own decisions on
safety.


Please drive safety, the world needs more Lotus fans...
-E
1969 FHC 8624






To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links












To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links
Steve B.<br>1969 Elan S4
poiuyt
Third Gear
Third Gear
 
Posts: 346
Joined: 23 Feb 2004

PostPost by: john66s3 » Wed Nov 03, 2004 8:58 pm

I have had luck with Moss Motors having the original style 2 and 3 point
belts with reels, etc. - John

----- Original Message -----
From: "Steve B" <***@***.***>
To: <***@***.***>
Sent: Wednesday, November 03, 2004 2:37 PM
Subject: Re: [LotusElan.net] RE: Seat belt choice




Where can I get replacements for the 3-point belts in my 1969 S4?

Thanks,

Steve B.


--- In ***@***.***, "John Oglesby" <[email protected]> wrote:
David - The issue is that 4, 5 or 6 point belts where your shoulders
are

both held back equally can cause you to submarine - particularly on
the

"rebound". Correctly installed crotch belts will help, but they
cannot be

properly installed with a stock Elan seat - you need a race seat
where you

are literally sitting on the crotch belt. All you do with the belt
wrapped

around the front of the stock seat is build up momentum before they
get

tight - OUCH!. And who is going to religously put them on in a
street car?

Three point belts are designed so your upper body twists, which
keeps you

from submarining under the lap belt. The original Elan three point
design

would have had to meet federal guidlines at the time. But, I would
be very

worried about an aftermarket system that isn't set up to meet the
specifications called for by the unit. In particular, I would
suspect that

the stock mounting points aren't correct for ANY aftermarket belt.
I use

Schroth belts in my track car and went carefully through the proper
mounting

process with the Schroth US supplier here in Boston. I have also
seen many

videos from Schroth tests showing submarining with incorrect
installations -

they are not very pretty. This is not something to "home engineer".
If you

want to move away from the stock belts I strongly advise that you
talk to a

knowledgable supplier, not someone who will just sell you some
belts. Here

in Boston that would be HMS Motorsports.

John
66 Elan S3 DHC
88 BMW M3 Track Car

----- Original Message -----
From: "ALLEN, David" <[email protected]>
To: <***@***.***>
Sent: Wednesday, November 03, 2004 8:01 AM
Subject: RE: [LotusElan.net] RE: Seat belt choice



This is a very interesting discussion on an area which I have spent
no time,

(other than replacing the mounting plates because they had rusted
away!)

Am I correct in believing the problem is in the event of a crash,
some

designs hold your shoulders back in the seat and consequently, your
body can

slide under the lower belt?

If this is so, what is the optimum design for a conventional 3 point
belt? I

would take the approach of having the belt professionally modified
(no, I

would not do it!) or moving the location of the mounting points. Are
fixed

belts better?


David


-----Original Message-----
From: Evan C [mailto:[email protected]]
Sent: 02 November 2004 18:51
To: lotus elan newsgroup
Subject: [LotusElan.net] RE: Seat belt choice



The only .and I repeat only..safe set up is the stock unit but not
that

great.or a set of 6 points.with a crotch strap that you attach to
the same

place as the lap anchors.and you actually SIT on the crotch belt.and
it

attaches to buckle..

I have a set in my Seven.if you want pictures. I have 4 point in my
Elan..and I am always afraid of submarining under the belt.I am sure
I

would..

Tony V

Tony,
This is not entirely correct. The belts in a 5 or 6 point harness
cannot

eliminate the forces that produce submarining. The transfer of
mass still

occurs- albeit to al lesser extent.
In the dynamics of a crash the most effective preventative measure
for

submarining, not respective of belt configuration, is to increase
the

incline of the seat pan.
Submarining is set in motion by an unimpeded horizontal sliding of
the

drivers lower mass accompanied by the fixation of the upper body by
the

shoulder belt(s). In order to prevent submarining the drivers mass
must be

located top and bottom. This can be done by increasing degrees
with a

3,4,5,or 6 point harness. It can also be accomplished by loading
that mass

into a surface that will counteract its motion, or better yet a
combination

of the two approaches. Additionally, a 5 or 6 point harness will
locate

the driver with minimal excursion - BUT - the loads on the belts
will be

significantly higher than if the harness is used in conjunction with
an

inclined seat pan.

Been there - crash tested that. The dummy died of internal
injuries.

Period.

Bottom line - these are old cars, and the belts they came with
(while better

than nothing) are still 40 years behind the current understanding of
crash

dynamics.
You have to do your own research and make your own decisions on
safety.

Please drive safety, the world needs more Lotus fans...
-E
1969 FHC 8624






To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links












To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links









To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html


http://www.lotuselan.net/publish/legal_stuff.shtml
Yahoo! Groups Links
John

66 S3 DHC
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