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Inertia reel belts


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I know this has been done to death but mainly with regard to MX5 seats. I have moved away from the 'dark side' and replaced my MX5 seats with restored TR4A ones (I've yet to undertake a long journey yet so the jury is still out).

However the upper mounting for my 3 point static belts is placed such that the cross belt constantly slips off my shoulder unless I have it so tight I can scarcely breathe.

My questions are:

1. Which model of belt should I choose (I'm erring towards the type that are adjustable for angle)

2. Precisely where should I place the mountings

3. Which stalk should I choose (The Stag I used to have had stalks that were really too long and were a pain).

I am attaching pics of the current set up

Any advice would be welcome

Andy

IMG_4121.jpeg

IMG_4119.jpeg

IMG_4118.jpeg

IMG_4120.jpeg

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47 minutes ago, ctc77965o said:

The top mount should be on the rear wheel arch, as shown in the WSM

Thanks. That's what I thought. However, there seems to be no mention of seatbelts or mountings in my Workshop Manual (510322 2nd ed. 1965 though my car is 1962)

Andy

 

Edited by Ocheye
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Although it’s referring to lifting the body this is where the original seat belt mounts were on early cars.

Stuart

BB40C156-958A-4743-83DA-2DBE268B7C24.jpeg

Edited by stuart
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I would still welcome advice on which inertia system would be the best and precisely where the various mountings should be located bearing in mind it is a TR4 with no rear seat squab

Andy

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1 minute ago, Ocheye said:

I would still welcome advice on which inertia system would be the best and precisely where the various mountings should be located bearing in mind it is a TR4 with no rear seat squab

Andy

If you dont mind new style belts then Securon 500/30 will do fine http://www.securon.co.uk/seatbelts_layouts.htm

Fit the reels to the bottom sides of the rear arches and then at the top of the arch fit the other bracket the belt slides through and the bottom fastener is in the base of the "B" post. The stalks bolt through the rear sides of the tunnel on a TR4.

If your feeling flush and want period type belts then these guys are very good. https://www.quickfitsbs.com/classic_cars_seatbelts.php

Stuart.

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On 2/1/2020 at 1:54 PM, stuart said:

If you dont mind new style belts then Securon 500/30 will do fine http://www.securon.co.uk/seatbelts_layouts.htm

Fit the reels to the bottom sides of the rear arches and then at the top of the arch fit the other bracket the belt slides through and the bottom fastener is in the base of the "B" post. The stalks bolt through the rear sides of the tunnel on a TR4.

Many thanks Stuart.

Would it be advantageous to fit the 514/30, Stuart? I assume the slide bracket would need to be slightly angled towards the outside shoulder area. I don't suppose you have a pic of this top bracket in situ.

Andy

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14 hours ago, Ocheye said:

Many thanks Stuart.

Would it be advantageous to fit the 514/30, Stuart? I assume the slide bracket would need to be slightly angled towards the outside shoulder area. I don't suppose you have a pic of this top bracket in situ.

Andy

I have used those but as the reels are only handed one way then one side sits nice but the other has to sit further out to clear. The reels for them would be mounted on top of the arch and only really suit a Surrey top car otherwise they can be a bit in the way of the hood mechanism, its doable but they do intrude a bit.

I dont have pictures Im afraid.

Stuart.

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10 hours ago, stuart said:

I have used those but as the reels are only handed one way then one side sits nice but the other has to sit further out to clear. The reels for them would be mounted on top of the arch and only really suit a Surrey top car otherwise they can be a bit in the way of the hood mechanism, its doable but they do intrude a bit.

I dont have pictures Im afraid.

Stuart.

Thanks again. How strange that they are only handed one way.

Andy

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On 2/1/2020 at 1:54 PM, stuart said:

 

Fit the reels to the bottom sides of the rear arches and then at the top of the arch fit the other bracket the belt slides through and the bottom fastener is in the base of the "B" post. The stalks bolt through the rear sides of the tunnel on a TR4.

 

Stuart.

As you can see from my pics, the bottom fastener is somewhat forward of the base of the "B" post and the stalks (in my case straps) are located on the floor next to the tunnel. As I don't really want to change the perfectly acceptable carpets and weld the holes up, could I get away with keeping these where they are?

Andy

IMG_4121.thumb.jpeg.442fd118fa8afc1ad4d10294872f3fd8.jpeg

IMG_4120.thumb.jpeg.60c36f3f30d0cb1b36c226d15ef1c328.jpeg

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2 hours ago, Ocheye said:

As you can see from my pics, the bottom fastener is somewhat forward of the base of the "B" post and the stalks (in my case straps) are located on the floor next to the tunnel. As I don't really want to change the perfectly acceptable carpets and weld the holes up, could I get away with keeping these where they are?

Andy

IMG_4121.thumb.jpeg.442fd118fa8afc1ad4d10294872f3fd8.jpeg

IMG_4120.thumb.jpeg.60c36f3f30d0cb1b36c226d15ef1c328.jpeg

I suspect the inner floor ones maybe OK as theyre probably screwed into the chassis (I would check to make sure that is so or that there is a sufficiently large re-enforcing plate underneath it) and the same applies to the other, however due to its location the outer floor one is not ideal for any inertia belt fittings. I would check to see of you have the original lower fixing points which were re-enforced from the factory. One at the base of the "B" post and one at the rear side of the tunnel and if present go back to them and just add a grommet with a bit of sealer to the others.

Stuart.

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  • 2 years later...

Getting there at last. As I'm about to fit my new (to me) leather mx5 seats, it is time I changed from my static belts to inertia reel. 514/30 is my preference.

My TR4 has a hood and no rollover bar (at present). Does anyone have pics or schematics showing location of the reels and guides on a car of the same spec as mine?

It is obviously different if you have a surrey top or roll over bar as there is no concern over fouling the hood and the guides can be incorporated into the r/o bar

Andy

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On 2/4/2020 at 12:08 PM, stuart said:

I have used those but as the reels are only handed one way then one side sits nice but the other has to sit further out to clear. The reels for them would be mounted on top of the arch and only really suit a Surrey top car otherwise they can be a bit in the way of the hood mechanism, its doable but they do intrude a bit.

I dont have pictures Im afraid.

Stuart.

I fitted the 514/30 on Stuart’s advice some time back. Correct, they are not handed unfortunately so I made a mounting plate up for the driver’s side.
 

To be honest it didn’t look too bad when fitted, but the key is to double drill and bolt the plate through the arch, otherwise it could possibly twist forward under inertia. Pictures attached.

 

FE0DF7AF-B395-4DEF-97B9-EABA6182BB27.jpeg

479B2047-30F3-470C-BA2E-7211246A0464.jpeg

ED2420B2-356B-4726-B5D2-2FEAF488C866.jpeg

8C8D6590-4ACF-4822-B15B-1AD377FC4CF6.jpeg

 

DD294F26-CF74-48F5-BC81-32A5FDAB7EC1.jpeg

Edited by boxofbits
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Andy,

I know you are not going to mount your stalks on the transmission tunnel, but it was mentioned as a choice earlier and just incase anyone else is thinking of doing it that way here is a tip.


Make sure the bolts you use are not too long.


When I first drove my car after a rebuild I got the impression that the silencer was hitting the ground after going over bumps. A look underneath and I could see the witness marks on the propshaft.
As the car was going over bumps the back axle was going up, and of course so was the rear part of the propshaft.
It was fine on the flat, but over bumps it was just going high enough to lightly touch the propshaft and make a sound (The same sound as a silencer hitting bumps.)


You need long arms to hold a spanner on the nut inside the tunnel and a socket on the bolt inside the car to remove the bolt to cut it down.
Easier to check it before you tighten it up.

Charlie.

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3 hours ago, Charlie D said:

Andy,

 


You need long arms to hold a spanner on the nut inside the tunnel and a socket on the bolt inside the car to remove the bolt to cut it down.
Easier to check it before you tighten it up.

Charlie.

Thats why when I build cars i weld re-enforcing plates and nuts into the shell for all the seat belt mounting points whether theyre having belts or not.

Stuart.

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On 8/20/2022 at 4:05 PM, Charlie D said:

Andy,

I know you are not going to mount your stalks on the transmission tunnel, but it was mentioned as a choice earlier and just incase anyone else is thinking of doing it that way here is a tip.


Make sure the bolts you use are not too long.


When I first drove my car after a rebuild I got the impression that the silencer was hitting the ground after going over bumps. A look underneath and I could see the witness marks on the propshaft.
As the car was going over bumps the back axle was going up, and of course so was the rear part of the propshaft.
It was fine on the flat, but over bumps it was just going high enough to lightly touch the propshaft and make a sound (The same sound as a silencer hitting bumps.)


You need long arms to hold a spanner on the nut inside the tunnel and a socket on the bolt inside the car to remove the bolt to cut it down.
Easier to check it before you tighten it up.

Charlie.

Thanks for your words of wisdom, Charlie

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On 8/20/2022 at 10:45 AM, Ocheye said:

Getting there at last. As I'm about to fit my new (to me) leather mx5 seats, it is time I changed from my static belts to inertia reel. 514/30 is my preference.

My TR4 has a hood and no rollover bar (at present). Does anyone have pics or schematics showing location of the reels and guides on a car of the same spec as mine?

It is obviously different if you have a surrey top or roll over bar as there is no concern over fouling the hood and the guides can be incorporated into the r/o bar

Andy

 

P1420349.JPG

^ This shows the present seat-belt geometry on Katie, my 4A.  I might only assume the same arrangement would suit a TR4.  The inertia reel was previously bolted to the sill, where the tail-end of the seat-belt also fastens, but it was in way of the seat moving back very far ..so I moved it to just above the step.  Initially I had just drilled (10mm if I recall) & bolted through the inner wheelarch and large + thick backing plates ..and I feel that was more than adequate as the seat-belt loading through that fastening is only ever in shear. 

Later on, I did stitch-weld those same plates in their same place under the wheel arch, just before repainting under those (for sake of rust deterrent), but I wouldn't have done so., had the trim not been taken out (to beat the front of wheelarch into a concave shape ..again so the seat might move even further back).

I've now removed the hood frame * ..as I've gone with the Surrey top.  If I were to have a roll-over-bar then I'd use that for the seat-belt's shoulder mounting.  I don't have one, and no will I.. but sometime, when I have the rear wing removed (for rust-preventative treatment), I'll most likely take the opportunity to move that seat-belt pivot point vertically upwards from the wheel-arch... to the very top edge of the body.  That of course cannot be done where a folding hood frame need to land, but ergonomically it would be better if it were higher up. 

Hope that helps,   

Pete

* TR6 soft-top frame and the fabric hood is for sale should anyone need one.!

 

 

Edited by Bfg
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14 hours ago, Bfg said:

 

P1420349.JPG

^ This shows the present seat-belt geometry on Katie, my 4A.  I might only assume the same arrangement would suit a TR4.  The inertia reel was previously bolted to the sill, where the tail-end of the seat-belt also fastens, but it was in way of the seat moving back very far ..so I moved it to just above the step.  Initially I had just drilled (10mm if I recall) & bolted through the inner wheelarch and large + thick backing plates ..and I feel that was more than adequate as the seat-belt loading through that fastening is only ever in shear. 

Later on, I did stitch-weld those same plates in their same place under the wheel arch, just before repainting under those (for sake of rust deterrent), but I wouldn't have done so., had the trim not been taken out (to beat the front of wheelarch into a concave shape ..again so the seat might move even further back).

I've now removed the hood frame * ..as I've gone with the Surrey top.  If I were to have a roll-over-bar then I'd use that for the seat-belt's shoulder mounting.  I don't have one, and no will I.. but sometime, when I have the rear wing removed (for rust-preventative treatment), I'll most likely take the opportunity to move that seat-belt pivot point vertically upwards from the wheel-arch... to the very top edge of the body.  That of course cannot be done where a folding hood frame need to land, but ergonomically it would be better if it were higher up. 

Hope that helps,   

Pete

* TR6 soft-top frame and the fabric hood is for sale should anyone need one.!

 

 

Thanks Pete

 

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