Seat mounting

[steve1506]

I have made a subframe as per photo to fix my seats to the floor plate. Would it be a good idea to weld the runners to the 10mm thick bars or should the 8 mm bolts into tapped holes in the bars be sufficient. Your views would be appreciated 

Steve  D

[RallyChris]

I think the first question is what are the subframe bars attached to?

There shouldn’t be any need to weld the seat runners to the floor, and bolts into your bars should be sufficient, as ultimately the seat belt fixings are going to be what holds you (and the seat) securely from lifting up or moving forward in the event of a rapid deceleration.

The IVA inspector is going to be more interested in the security of the floor under the seat to stop the seat dropping through the floor. I’ve read numerous comments on here and other kit car forums about needing either something continuous running across the car under the seats and attached to the chassis at each side, or a structure in each side of the tunnel welded together at the centre tunnel.

Chris 

[steve1506]

Chris,

Thanks for your response, I have fitted the GBS IVA floor panel which is a 3 mm steel plate across the car supported in the center by the structure in the photo below and the chassis tubes at the side. The center structure also has 5 mm plate spreaders so that the floor and IVA panel are sandwiched in between, I used the 10mm bar to add additional support to the runners and to lift the runners off of the floor so that the seat would run over the rear sierra frame fixings which you can see in the photo.  May be a bit over engineered but I really don't think any of it is going to move in an accident. 

Steve D

[RallyChris]

In that case I don’t think you have anything to worry about, and with the GBS plate in place you could mount the seat directly to the floor without the additional cross pieces. 
 

On our 2B I have added a lot of structure above the floor level, so I have similar cross beams for the seat runners to sit on but they are welded in to the chassis at the sides, and to a lower longitudinal frame at the base of the tunnel. 
 

(Upside down chassis in the picture!)

 

[Foz]

Just another thought - I had spacers and metalwork under my seat runners which all worked fine but I later found out that when I fitted the hood my head was touching it and then I also realised that my head was above the roll bar.  I now have the seats lower, with metalwork under the floor.   I guess it all depends how tall you are and what seats you have, but it's maybe worth checking before you finally fix everything in position.

Steve

[steve1506]

2 hours ago, Foz said:

Just another thought - I had spacers and metalwork under my seat runners which all worked fine but I later found out that when I fitted the hood my head was touching it and then I also realised that my head was above the roll bar.  I now have the seats lower, with metalwork under the floor.   I guess it all depends how tall you are and what seats you have, but it's maybe worth checking before you finally fix everything in position.

Steve

Good point That’s something I will need to check . I have the Intrim Oddessy seats which fit really well. The runners are low profile so with the bar the seat base is about 30 mm off the floor which should be okay as I am not that tall

[steve1506]

3 hours ago, RallyChris said:

In that case I don’t think you have anything to worry about, and with the GBS plate in place you could mount the seat directly to the floor without the additional cross pieces. 
 

On our 2B I have added a lot of structure above the floor level, so I have similar cross beams for the seat runners to sit on but they are welded in to the chassis at the sides, and to a lower longitudinal frame at the base of the tunnel. 
 

(Upside down chassis in the picture!)

 

Chris I had originally planned to bolt direct to floor but having narrow seats the inner runner mounting fell in the cut out area of the Iva panel and would only be fixed to the SS floor which was a shame and not good

Steve D