Front Subframe Tie Bars
Turbo Mini Forums

Hi again, I'm running a fg flip front and am going to continue the rollcage tubing from where it meets the front bulkhead/top subby mounts down to the front of the subby to stiffen it all up.

My question is- should I make a couple of big dimples in the tube, or weld anything in to provide some crumple zone so if I have a bad shunt it doesn't end up putting all the force into the rest of the car and just crumples the subframe and tie bars instead?

Probably not worth worrying about too much but thought I would get opinions as I'm yet to make the tubes etc, and being a fg front there will be no "crumple" like you get with a tin front.

Thanks,
TC

www.topcatcustom.co.uk

I think there is a bit more engineering goes into crumple zones than just adding a random weak spot. I'd forget the idea.

Surely theres a bit more engineering goes into car body design than just putting a massive roll cage in the design!

I've got a good head and make stuff that never breaks for a living, so was picturing 2 points along the tie bars/tubes which had say 15mm dimples pushed in, so in the event of a major front end shunt it would cause the bar to fold into a bit of a Z shape, so that it doesn't force all the impact along into my shell.

I'm not committed to the idea but thought someone may have some thoughts!

www.topcatcustom.co.uk

Personally I think it is a very good idea to do what you can in the design if you have the opportunity - although I don't have a cage, I certainly took the loading into account when I made my brace bar.

I wanted to regain torsional rigidity and have deformation in the design so I made a single tube....



The torsional rigidity is from the section along the front and deformation is achieved in four places by the four curves which means the sides will deform into a twisted "Z" under impact.

No fancy calculations, just common sense IMO.

(EDIT - spelling/grammer)

Edited by Rod S on 16th Mar, 2012.

Schrödinger's cat - so which one am I ???