Quote:
Originally Posted by KAMBO
how much less would a chassis weigh if built in 2mm wall ali box section ?
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Steel weigh about 8750kg/cubic meter and aluminum about 2600kg/cubic meter - thus ally is about 3.37 times lighter than steel. Sounds good, but to get to the same tensile strength as steel, you have to up the thickness to be on par with steel.
When I built/ designed ocean going yachts for a living before retiring, many designs were built either in steel or aluminum. But overall the ally went 30% in size, thickness etc to comply to the same scantling as steel, but still these yachts turned out much lighter than their steel counter parts....
Back to the subject at hand; since we use 25 x 25 x 1.6mm tube for the frame, a meter length will weigh about 1.256kg. The equivalent in ally to be used should be 25 x 25 x 2.0mm and a meter length will weigh about 0.52 kg.
But to be absolutely safe you can up the ally to 25 x 25 x 3.0mm and a meter length will weigh only 0.78kg and a frame built of this over sized grade will be much stronger than the std steel frame and still be 38% lighter!