In the Avon Tiger there are extra bars to support persons weight but with the original chassis the floor panel is just welded on the bottom. Where are the seats supported? I take it not straight on the sheet metal! Im sure with my weight i would fall through if i went over bump!!! Do i need to add in supports?

P.S Im sure its 11.25pm not 10.25pm! Web site clock could be wrong or have the clocks gone back and i didnt notice?

I am about to start my project and i am also concerned about thisas i weigh about the same as a small planet.
Correct me if im wrong but surely welding a couple of bits of RHS to mount the seat on cant harm can they? however this will raise the seating

erm

This must be the 3rd time in a week I have typed this....


Weld in two extra bits of RHS across the floor where you are bolting your seats in. It will stiffen the floor no end and only adds about 2 kilos or so to the car. After you have done that you could use thinner steel or even alu on the floor.


atb

steve

If your so concerned about the floor falling thru, something that i would think is impossable if the floor was fully welded (as mine) to all of the rhs tubes inside and outside, (outside welds need grinding off to fit alui sides)
why not weld the floor on top of the bottom rails, this would mean 2 floor pans and some rejiging of the transmission tunnel to fit
some builders have alui floors and they are just riveted to the bottom rails, but i must say that i did not like that idea

steve

i fully welded mine with 1.6mm steel and the floor still moves.

If you managed to weld the floor so there is no distortion, perhaps it different. On my car fully welding created a little unflatness to the floor, which then proceeds to ping back and forth when weight is applied to it. Its exceeding crappy unless you add extra bracing.

why all the obsession with weight saving? a couple kilo for a stable seat mounting is gonna cost what - 0.02 of a second????


atb

steve

I was going to fully weld the floor in but wondered if this would bow the chassis or cause any of the box section to become weak?

I can't see that as a problem really.

How many cars have had a problem with the bottom rails failing?

What are the other options?

Not fully weld and potentially have the floor flex? I certainly wouldn't want that.

Or the other option? Rivet the floor to the bottom rails. Now that WOULD weaken them I'd have thought. Screw that.

My floor is welded inermitantly,somewhere on the list this is mentioned by others.

i'm not sure if the intermitant weld would be stronger,but it does allow the flex of chassis floor so the welds wont pull.

I am fitting 25mm RHS rail to rail under the seats,as said before this will stop the floor ping no end

Bob,

I had fitted 25mm box section rails that had 3mm x 25mm strip welded on the ends that rested on the inside and outside rails (as posted on the yah.. Indy list). This made the seats feel well supported. Unfortunately one of my SVA failure points was that the seat belt upper anchor points was about 25mm too high. The inspector said that it wouldn't have failed if the seat had been bolted directly to the floor ... Ugh. When I mesured it it seemed ok but his jig measured a fail. He mentioned that the measurement in the SVA manual is trying to set the reference point at the centre of the hip, with the MK fibreglass bucket seats this position seems a bit subjective.

The point is - check that your still OK for height. I'm looking at a comprimise - can't bring myself back to that sinking feeling, even for a pass!

Cheers,

Colin

PS how far away from the SVA test are you (in time)?

Colin

Christ something else for me to think about
Message in ya mail
BOB

I just aquired a built chassis that had then engine/gearbox and running gear attached. I stood on the floor pan (fully welded) and lifted the engine.

I'm over 16 stone and the floor didn't even creak........

Guess the floors strong enough!

If your concerned about the floor why not weld two or three lengths of 3mm flat bar across the chassis members below the steel floor that way you add strength without raising the seat hight. There may be some flex still but it will not come away.

I have not done it yet, but I intend to plug weld the floor (I am going to use 20g)at 60mm intervals and then weld 13mm RHS at 150mm intervals londitudinally (underneath)along the floor. This will add (almost)nothing to the weight but will stop any flexing. 13mm RHS is only £3.85 for a 6.1m (20ft) length and can be used for all kinds of stuff including double diagonallly bracing of any untriangulated appertures and for making a frame for the bonnet and scuttle if you are making your own (it bends realy easily over a wooden former).
When I have done it I will post the pics
Mark