Seatbelt mod part all made and fitted

[B16JUS]

after many a drive untwisting the seatbelt it was time to do this mod

made by a local company and powdercoated took 5 min to fit and my god makes putting on and off so much easyer

next on the list is all new gauges from stack

[GreenV8S]

B16JUS said:

next on the list is all new gauges from stack

Hang on to the originals, a working set of TVR gauges is worth money.

[B16JUS]

GreenV8S said:

B16JUS said:

next on the list is all new gauges from stack

Hang on to the originals, a working set of TVR gauges is worth money.

Yes was going to sell them all on apart from the speedo to prove millage before new speedo fitted

These are the new dials that are going in, all made by Stack with black face and led backlight

[moffspeed]

ah the old seat belt mounting chestnut...

I'm so keen to do something similar as one of the few negative experiences of "S" ownership is disentangling the 'belt and persuading the inertia reel to take up the slack. Someone has previously suggested a similar mod. but the concern was expressed that, in the event of an accident, the load would be in the long axis of the mounting bolt and encourage failure as opposed to the original design whereby the load would be at right-angles to the mounting bolt.

Anyone with an engineering background care to comment ?

[B16JUS]

moffspeed said:

ah the old seat belt mounting chestnut...

I'm so keen to do something similar as one of the few negative experiences of "S" ownership is disentangling the 'belt and persuading the inertia reel to take up the slack. Someone has previously suggested a similar mod. but the concern was expressed that, in the event of an accident, the load would be in the long axis of the mounting bolt and encourage failure as opposed to the original design whereby the load would be at right-angles to the mounting bolt.

Anyone with an engineering background care to comment ?

I would say if you spank a S that hard that the direction of the bolt of the seatbelt is a issue, you would be injured badly anyway

[SteveOS3]

I sent my insurers the spec's of the mod', some photos' and a link to the tvrsseries.com webpage and they were happy to approve the mod; it is worth checking with your insurers that they are ok with the mod too.


SteveO

[Ragtop]

moffspeed said:

Anyone with an engineering background care to comment ?

Firstly, the tension in the part of the belt that passes over your shoulder (approximately in the horizontal direction) is reacted by the same tension in the part of the belt that goes into the reel (approximately in the vertical direction), hence the reaction at the buckle is ~45degrees to the bolt axis regardless of whether it's horizontal or vertical.

Secondly, broadly speaking, bolts are stronger in tension than lateral shear.

Thirdly, provided the threads are in good nick, the force in the belt required to load the bolt(s) to ductile failure would cut you in half if the belt didn't snap first.

I've done this mod, and it works extremely well.


Regards,
Graham

[phillpot]

Ragtop said:

lots of sensible stuff....

I'd have thought the "weakest link" and therefore first thing to give, by a long way, would be the bonding of the mounting post into the body tub?

Even back in the 80's that must have passed some sort of crash testing?

[B16JUS]

Ragtop said:

moffspeed said:

Anyone with an engineering background care to comment ?

Firstly, the tension in the part of the belt that passes over your shoulder (approximately in the horizontal direction) is reacted by the same tension in the part of the belt that goes into the reel (approximately in the vertical direction), hence the reaction at the buckle is ~45degrees to the bolt axis regardless of whether it's horizontal or vertical.

Secondly, broadly speaking, bolts are stronger in tension than lateral shear.

Thirdly, provided the threads are in good nick, the force in the belt required to load the bolt(s) to ductile failure would cut you in half if the belt didn't snap first.

I've done this mod, and it works extremely well.


Regards,
Graham

So was i right in saying for this to be a issue you would already be dead / inhalf or very injured already lol

[moffspeed]

maybe I should buy a Volvo 240...

But seriously is this seat belt mod available anywhere ??

[Andy Lynch]

moffspeed

I am looking to get a pair made, if you want a pair, PM me and I will get 2 pairs made, for cost price.

Andy

[TurboTony]

Any reason why the 7/16" rose joint cannot be used? I believe that someone had done this.

[B16JUS]

moffspeed said:

maybe I should buy a Volvo 240...

But seriously is this seat belt mod available anywhere ??

I used a company in Romford if your local

[Gerald-TVR]

SteveOS3 said:

it is worth ESSENTIAL checking with your insurers that they are ok with the mod too.


SteveO

I think

[GreenV8S]

Gerald-TVR said:

I think

I think too.

From an engineering point of view it looks OK to me, but it's obviously a safety critical modification which means it is a relevant fact and must be disclosed to the insurers.

[v8s4me]

TurboTony said:

Any reason why the 7/16" rose joint cannot be used? I believe that someone had done this.

None at all IMHO - see here

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Am just about to renew my insurance so will update if there are any issues.