How can torsional strength be improved on a chassis frame?
Answers:
Depending on the chassis in question, you can always 'box' the frame as well. Most frames, depending on the year, are a C-channel type design. Closing in the open side and making the frame a box style increases the strength considerably. This is a common fix for those that like to take their trucks into some serious off-roading.
Obviously, as mentioned already, cross bracing is always good as well, but can sometimes interfere with other things below the vehicle. A good welder can guide you through the pitfalls and make sure you can run all the apporpriate lines (brakes, fuel, exhaust, etc) and cables (emerg. brake) that you need.
It is done all the time look at NASCAR building a cage and welding it to the frame remember TRIANGLE is your friend.
For example in 1957 when they made the Chevy Bel air Convertible the had problems with the large chassis flexing and twisting. Problem was solved by making the cross members x across the frame from behind the engine to the rear axle. If you going for speed and not so much looks then the cage is a good choice.
Yes the triangle is the most solid structure know to man,
Build a paper cube & pyramid, and try to crush each. you should notice you need more force with the pyramid.
(an X is a double triangle..)
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