Best Material for a roll cage?

[Jimbob]

Hi,

My next project is a custom roll cage for the 2. I'm still debating the pro's and con's of alloy and steel.

Any ideas?


Cheers,

James

[Chris \'aka rustboy\' Amm]

surely alloy would bend? i thought most were steel. if you have the cash use titainium

[Jimbob]

admitedly alloy is a more ductile than steel but offers excellent weight saving.

Thought about Ti, but where do you get it from?

[Chris \'aka rustboy\' Amm]

no idea mate sorry!

[michael]

Toilet roll tubes and sellotape?

Mild steel (cold drawn) is the usual budget option I believe, chromoly is stronger so you can use thinner tubing or smaller walled stuff to save weight (eg: .095 Chromoly vs. .120 wall Mild steel).

[Lauren]

Usually they are steel, though expensive alloys can be used (but you probably don't want to go there).

If you are a demon welder then you could copy a roll cage i guess.

I'm all for fabbing your own stuff, but wouldn't it be easier to buy one? You can get them from Japland or buy over here.

What do you want it for?

Ie is it to really stiffen the chassis up or is it purely for looks? there are a number of companies that can do either: Safetydevices, Caged, Rollcentre etc.

One other thing, a rollcage in a road car can do more harm than good in an accident if you bash your head on a bar it will give you a headache at a least!

Also I would say you really should have appropriate seats if you are going for the racer look.

[MegatronUK]

Is it going to be used for road or track use? If track, and you're thinking about getting competetive then you're wasting your time, IMO... buy a proven and tested one that meets FIA specifications (like the ones that Lauren has just mentioned).

[Bender Unit]

Saftey 21 is Japans biggest roll cage manufacturer. They make their own as well as Cusco and Border cages all to suit the SW20 chassis. 4 point or 6 point. Saftey 21 make them in steel and the Cusco range come in alloy. The alloy cages are about double the price.

I have a Saftey 21 steel cage which I managed to land for £50! Quality of the cage is excellent, welds are very good etc. Haven’t checked fitment yet but I severely doubt there will be any issues. All I need to do with the cage is spray it the colour I want. I also intend to get some sturdy back plates made up where the cage bolts through the car.

If you want to avoid bashing your head then some padding around the head area will suffice.

Regards

James

[Jimbob]

I'm considering going into the chassis on the car, i.e cutting out bits and welding it in. I'm no welder but my mate is! Not sure how to play it as yet? I like the leather seats etc..............but when I get my respray this spring It'll all be out, i might leave the car stripped down and have the rollcage welded in then painted, then get some fancy buckets?

James

[Lauren]

I'm considering going into the chassis on the car, i.e cutting out bits and welding it in. I'm no welder but my mate is! Not sure how to play it as yet? I like the leather seats etc..............but when I get my respray this spring It'll all be out, i might leave the car stripped down and have the rollcage welded in then painted, then get some fancy buckets?

James

I'd be careful with cutting bits out of the chassis, you want to make it stronger not weaker. No rollcage (unless its an integral part of a spaceframe chassis) should require cutting of the chassis.

The best cage for a monocoque chassis is a weld in one, that is you weld plates between the cage and the surrounding areas ie A, B, C pillars and obviously the floor.

As for bucket seats. Yep they are great, but can be something of a PITA for road use as entry and egress is anything but elegant. Also a regular seat belt would need to be threaded through the harness slots and may not work properly at all. I gave up with a regular seat belt in my SC and just used 4 of the six points for road driving. Was incredibly annoying on short trips though as i'd spend more time buckling up/removing lap belts from my bum, than driving.

I think its liveable, but you are starting to get fairly hardcore once you go putting bucket seats in. Also you will likely find that you have to rigid mount the seat by bolting it straight through the floor, so again you lose some practility.

I guess you could use reclining 'bucket' seats as a halfway house between the hopeless stock seats and a proper competition bucket.

HTH

[Fizzy]

when Lauren says expensive alloys....she means it!!! Alloy as in aluminium was banned from roll cage manufacturing 15? years ago!!! And probably for a good reason! Its soft and brittle