shoulder belts for Intermechanica Speedster.

Really bad idea. The shoulder portion needs to attach above your shoulder or you risk spine compression in an accident. Unfortunately, there’s no place to mount a bolt or a ring in a Speedster because it’s in free space.


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Thanks

 

You would have to install a functional roll bar to run the shoulder belts in order for it to withstand the stress of an accident. Not saying it can't be done but it's not as simple as just bolting in a set of shoulder belts.

Can you post pictures of your seats and also your car so we can see what you have to work with. 

I’m definitely in favor of going to the trouble of installing a roll bar so you can have a 4-point harness.  Bending the steering wheel with my face helped neither the wheel nor my face.

One of the members on here, Bob Carley, had Henry at Intermeccanica build a roadster with a Porsche 993 drive train in it.  Bob also asked for a decent roll bar set up with seat belts similar to what you're looking for.  Here is a video of that build and, while it's a bit long, you'll see how the car was built and how the roll cage is integrated into it.  It's a really slick build.

Thanks to everyone so far. Here are pics of the car and interior

After Lane decided to modify his steering wheel with his face, I started considering going with a seat with integrated brackets and 4 or 5 point belts.  Lane found these and it looks like they would fit in a Beck (they have the most spacious interiors of any of the replicas), but not sure about an IM.

This would be far less tear up than a roll bar.

I winter my car at Special Edition, and when I considered it, the seat delivery timing wouldn’t work out for this calendar year, so I dropped it.

I’m also not sure that my butt would fit in the seat.  I’m hoping that someone else can be the Guinea Pig :-).

I’ll reconsider this winter.

http://www.classiccarseats.com...ghtanddimensions.php

I forgot about those seats.  Yeah, that'd be easier than the roll bar.  Tom, the seats don't look any narrower than the Beck ones.  I make no claim to know anything about your butt (), but I'll bet it would fit.

Lane, how would the seats help?  Without a roll bar there is still no point above the shoulder to attach the shoulder belt.

Don Torrey posted:

Lane, how would the seats help?  Without a roll bar there is still no point above the shoulder to attach the shoulder belt.

The seats are made with a frame and it has an optional metal attachment that routes the belts above your shoulders that they call the “Trips harness device.”

http://www.classiccarseats.com/trips-harness.php

Which means that although the end mounting point may be below the shoulder, the (not sure what to call it) point of, um, pressure(?), the fulcrum, the whatever is still higher up.  I could be totally wrong.

If you end up with belts over your shoulders, a 3-point MUST be higher than the shoulder.

If you go 4 or 5 point, a 10 degree down angle on the belts is OK, and can be up to 40 degrees depending on seat design(this is according to SCCA and Porsche club racing specs). Spine compression is not an issue on my installation, for my height. My belts go over the shoulders and then go down about 10 degrees and through the firewall. They then wrap around a chassis tube that goes across the engine side of the firewall up high.

Since you have all that room in a Speedster, you guys can't do what I did. If I had a Speedster I'd go for the Trips device(and corresponding seats) and a 3 point belt. This would work very well for the street.

A lap belt keeps you in the car and allows you to fling around like the end of a bullwhip. Never again for me. 

"A lap belt keeps you in the car and allows you to fling around like the end of a bullwhip. Never again for me."

Yeah, what he said.

If you look at the roadster seats on an IM, they have the shoulder belt attached to the upper edge of the seat in a similar manner but not exactly like that classic car seat. 

While, it may not be high enough for all body styles, I mean human  if you fit the seat it is a better system.   Now for those IM's that are roadsters and go to the UK they have a high shoulder belt arm welded on the frame to meet the seat belt regulations for the 3rd point. 

On my recaro seats, a much higher back rest seat, my shoulder belt goes on top of the seat just like the roadster seat and it is slightly above my shoulders so it does the job but may not be officially high enough by standards.  

I’m 5’7” and the roadster 3 point belt worked pretty good for me. So for short folks switching out to roadster seats might be an option. 

And yes a Beck has a more roomy interior than an IM. 

Possible to get what the seat belt look like from the back @550 Phil

@calmotion the belt roll is either bolted to the floor or rear seat area and fed up in the bracket,  note the drivers seat picture,  and the hip belt portion to the body on the side of the seat for the three point harness.

@IaM-Ray I have the same seat and was think of using Trips device discuss above or shoulder belts 550 Phil is using 

If you look at this picture.. you can see a bolt is protruding in the edge of the back of the seat.  A belt clip that feeds and holds the belt is bolted to it and the belt fed through.  this is how it works on the IM builds. 

 

 

 

 

 

I no longer own car. Belt role bolted to base of rear seat where there is car frame.