Hi!

What steel quality should be used for the steel tubes in the space frame? Does the book tell? I can't find it.

Best regards,

stock grade mild steel is fine will most likeley be erw generally the higher the grade of steel the harder, the harder the more brittle also some flex in the chassis is largely considered a good thing as rock solid can give a harsh (but accurate) ride. So 50b etc would be unnecc. cost addition but if you want super stiff consider using alu. but pricey and not so easy to work for first time.