Sorry if this has been covered before. But i was wondering what the gauge/thicknesses should be on the book/locost chassis tubes and suspension tubes.

When i recently asked for 25x25 16swg at a steel stock holder, i was told that it wasnt very common. Something called erw, and that i should be using 25x25 shs 2mm thick.

Now im totally confused what type of material i should be using.
Thanks in advance for any help.

[Edited on 23/6/04 by ChrisS]

try either

http://www.isg-steel.co.uk/5.shtml

as they stock 1"x1"x16g erw for main chassis

or

http://www.parkersteel.co.uk/macros/Hierarchy.mac/Matrix?VisitorID=4XXI11RIIT4&Status=guest&table_ref=40

who do 25x25x1.5mm erw both have counters in kent

erw is electric resistance welded (or something like that), it has a bump down the inside where it got stitched up. some people say this makes it unsuitable for use in suspension arms as it might make a weak spot. this is used by nearly everyone for the chassis, including ron in the book (he never called it erw but it is). suspension tubes are (IMHO) best made in round tube, maybe 25mm diameter and 2mm thick. mine currently are 19mm SQUARE 16g erq, and i dont feel happy with them. But it has driven and they havent failed yet, i think they will fail on a hard bump one day though.

I have used 25x25 mm 2mm thick mild steel tube for chassis, makes it heavier but no stronger. Its just what my local steel stockist had at the time. Suspension I used steam pipe, it said medium thickness on it. It has 3mm thick walls but is not seamless. Please don't anybody tell me I used the wrong stuff as it has taken me 3 years to get to the point where I am fully welding the chassis and I would rather be blissfully unaware .

Did someone use CrMo for their Rollcage and wishbones? Or T45

[Edited on 23/6/04 by gys]

Another question:
Did someone use round tubes instead of the 25x25 rectangular tube...

Dax uses round tube for their top version of the Rush MC.

there is someone who built a locost for hillclimbs and sprints who made it from round tube. Said it was probably much harder than square.

1"x1" 16g is what you need. You are mixing imperial with metric. You can get 25x25x1.5 some places but it isn't common. I found some and the tube corners are much squarer than 16g, also it feels thinner to weld. The place I use carries loads of 1x1 16g in stock but doesn't do the 3/4", only 19mmx2mm.