4130 chromoly tube for rollcages - where to buy cheap?

[gmacrae]

Hi guys. Looking to buy 30 or so metres of chromoly tubing for a couple of cars rollcages - where does the best price?

[Bazda]

No such thing as cheap 4130.

[evil_si]

Afwe (advanced four wheel equipment) in auckland use to good prices on cromoly tube

http://www.afwe.co.nz/

[gmacrae]

Afwe (advanced four wheel equipment) in auckland use to good prices on cromoly tube

http://www.afwe.co.nz/

Mint, cheers dude

[Mr Ree]

What are the different MANZ requirements for welding this compared to mild steel?

And does it double? triple? quadruple the cost?

The main benefit I can see is not just the reduction in weight, but where the reduction occurs, E.G high up in the car

[GOLDAE86]

Cardwells also supply it also! I believe the rules changed regarding roll cages built with it. I believe the tube can no longer be 1.6mm wall thinkness so using 2.4mm 4130 tube is just expensive and weighs the same as mild steel.
Please correct me if it has changed again but building a cage out of 1.6mm 4130 tube must have an engineers cert done before it can be built.

[Bazda]

I know the Main hoop needs to be larger in diameter now.
Think from 38.1 to 41mm

[fxgt race]

Only because I am using the new motorsport manual to stop the computer overheating . Unrapping it and main hoop is 44.5 x 2.5 or 50 x 2.0 for 4130 and steel. other bars 38.1 x 2.5 for both 4130 and steel, door bars 38.1 x 2.5 or 40 x2.0 for steel and 38.1 x 1.6 or 40 x 1.6 for 4130.

Best to ring motorsport nz to get it right.

[Distrb]

What are the different MANZ requirements for welding this compared to mild steel?

And does it double? triple? quadruple the cost?

The main benefit I can see is not just the reduction in weight, but where the reduction occurs, E.G high up in the car

MANZ don't care. MSNZ does. To the point that the use of 4130 alloy steel tube is restricted solely to MotorSport NZ registered safety cage manufacturers who have been granted ‘MotorSport NZ Recognised Manufacturer’ status. 4130 also needs to be tig welded.

These days the benefit in weight reduction is only really one you would realise if you were requiring a very extensive rollcage (aka lots of optional members which are allowed to be thinner wall thickness when using 4130) , because the weight of the principal structure is the same if using mild steel or 4130. Even then the savings are negligible.

All depends how much each gram of weight means to you in the type of racing you do. to a select few it is the difference between winning and losing. to the most of us it means not much.

[Mr Ree]

Thanks for the insight everyone.