Fitting Seats - Do they just bolt through the floor?

[nickp 2]

Hi All

In order to get into an access panel (and to expand the access panel) to remove the silencer mounts (one of 2 broke, so replacing both), I noticed that the seats are just bolted directly through the floor. The floor looks like 3mm thick.

Is this right, or should there be some reinforcement?

The seat belts appear to be bolted through the chassis so I think they are ok.

Thanks

Nick

[blue 46]

Hi Nick 

Yes seats just bolt to the floor -all your doing is holding them in its the seat belt that holds all the impact god forbid the worse should happen 

[alanrichey 238]

The Superspecs all have a reinforcing piece of steel 80mm x 3mm across the width of the car to which the rear bolts of the seat (and the bottom seat belt mounting) are attached.  

[nickp 2]

Thanks all, I thought it was best to check before I put the seat back. 

 

[Snapperpaul 441]

For IVA they require load spreading washers under the floor, this is worth doing if you don’t have a support member or equivalent under the mounting bolts

[theduck 820]

If the floor is 3mm, that exceed the load spreader spec for IVA doesnt it?

[richyb66 1,116]

100x100x4 for fixed single seats according to Seat Belt Anchorages 19 section of the IVA manual.

My view is that this is still a bit weedy if the plates are on a thin panel. The movement of the seat under braking and conering will still flex the floor around the plates and could split the panel, particularly if the driver is a larger gentleman (or indeed lady). 

[nickp 2]

On 5/1/2019 at 7:26 AM, Snapperpaul said:

For IVA they require load spreading washers under the floor, this is worth doing if you don’t have a support member or equivalent under the mounting bolts

It’s already registered but I’d like it to stay in line with IVA standards. I’ve put some penny washers with lock nuts for now. Penny washers are currently 25mm  

 

On 5/1/2019 at 8:39 AM, theduck said:

If the floor is 3mm, that exceed the load spreader spec for IVA doesnt it?

The floor is 3mm. 

On 5/1/2019 at 9:14 AM, richyb66 said:

100x100x4 for fixed single seats according to Seat Belt Anchorages 19 section of the IVA manual.

My view is that this is still a bit weedy if the plates are on a thin panel. The movement of the seat under braking and conering will still flex the floor around the plates and could split the panel, particularly if the driver is a larger gentleman (or indeed lady). 

I’d say I’m on the chunkier side haha

I’ll try and find a plate to 100x100x4 that I can use and update. Currently with bolting through the 3mm there is a bit of movement

[AndyW 50]

On my Superspec I reinforced the seat mounting bolts through the floor pan with 40x40 4mm square steel washers from B&Q. 

[mdav1970 31]

For IVA i had to put a spreader plate going across the front, under the seat between the 2 front bolts. He explained that in an impact the weight is forced down onto the front on the seat. I think it also depends on what seats you use and how they are bolted to the floor. If they are flat to the floor, its different than if they have small load areas that could be forced through the floor in an impact. 

[Del1968 16]

Had mot yesterday and tester fails it on the emissions and the drivers seat as there was too much flex in the floor seat moved side to side a lot when it was up on the ramp I noticed it was just bolted at the back though the floor if I put 100 mm plates on and bolts in the front will this stiffen the floor up or was thinking angle iron running across the back and across the front will that work 

[richyb66 1,116]

Spreader plates on all 4  corners should get you through the MOT and is one of the suggestions in the IVA manual. I would do this first to get back on the road and then consider the angle iron or some box section as a longer term fix. 

It might take a bit of working out so it's better to be able to use the car while you're looking at it. 

[Del1968 16]

Thanks richyb66 I give it a go and see how it goes 

[MarkBzero 276]

Good enough for seat belt should be more than ample for seats

https://www.ebay.co.uk/itm/Seat-Belt-Plate-Fitting-FIA-Harness-Eyebolt-Back-Plate-7-16-Thread-ADV/352645993886?hash=item521b56d59e:g:h4IAAOSw8W5aU1oW

 

[mdav1970 31]

When my IVA failed on a similar issue with the seat mounting points, as I put before, I put about a 5mm metal plate right across the 2 front mounting points inside the car, then spreader plates under neither. This was suppose to reduce the effect of the forward & down force the seats would have in a crash.