Outer Limits 4x4 Board

Vehicle skin will be ZK fairlane, using most probably Gq running gear, and ford engine/box.

steel collected so far 150x50x3, 100x50x3, 75x50x3, and 42x3'ish CHS.

Just after some opinions regarding design really, plan is to have two 100x50x3 main chassis rails, running into 150x50x3 over the front and rear diff, then back down to 100x50x3

The 75x50x3 for most/all crossmembers, and some 75x50x2 along the factory sills, sills half notched to accept it.

Probably use some tube for shock/spring and front/rear crossmembers, as well as tieing into the parcel shelf and firewall areas.

The vehicle wont have much ground clearance, I want the compressed stance to almost lay the sills on the ground, so the rails above the diffs have to raise up heaps more than normal, hence the 150 deep section.

Road going cars I'd normally use just 75x50 primarily and in 2.5 and 2 wall, so to me the steel Ive got already seems well strong enough.

Any opinions would be great, havent done off road chassis before, no roll cage at this stage.

You should be talking to your engineer about this!!!

But that aside, Land Rovers have some of the strongest stock chassis in a 4x4. They have 2.5 mm wall on the older models, and 2 mm on the newer models, but this is laminated internally to at least double thickness around suspension mounts. RHS is 75mm wide throughout, and 75mm deep at the front, increasing to about 200 mm deep (LWB - 150 mm SWB) in the middle, and then decreasing again towards the rear.

Check this out
http://www.4wdmonthly.com.au/forum/show ... hp?t=36370

Thats a full on build up, its got me thinking, mine is monocoque chassis essentially, it still has distinct main members but the whole shell of the car helps, I guess with most 4wd and truck chassis the body just sits on top, so has greater requirements for structural strength, ie bending, etc.

I'm starting to think mine is more along the lines of a tube chassis or similar, as opposed to most typical 4wd's, and maybe that my choice of 150x50x3 may have been overkill. But the huge raise I will have over the axles creates larger bending loads as the overall depth of the chassis and in a sense the whole section of the car at those points is much shallower.

its good starting with nothing in the way.