Looking into building a frame for a hotrod I've seen different sizes used for different size vehicles such as 2" x 2" or 2" x 3" box tubing and circular steel tubing but I am unsure if a .188 wall is the norm. When building a frame is there a standard wall to use or is a .188 wall enough?

  • In this case I'd give a call to one of the hot rod frame manufacturers and ask about what thickness their frames are. This is an area where you want to copy the experts.
    – race fever
    Commented Mar 20, 2016 at 21:37
  • 2
    In this case would it be built for street use or some kind of competition use? If competition use, you have to follow the sanctioning body's rules for the thickness. Each has the capacity to be different. Commented Mar 20, 2016 at 21:50
  • @Pᴀᴜʟsᴛᴇʀ2 Good catch. I only thought about a street car.
    – race fever
    Commented Mar 21, 2016 at 2:43

1 Answer 1


If building for a street vehicle, according to this forum post, they say that for 2x3, 2x4, and 2x5, 0.120" wall rectangular tubing is more than adequate for car frames. If you have to go a bit thicker to find what you want, even better.

If you are building for competition use, you'll have to look up what their regulations state. Every sanctioning body will have their own rules which must be met to run in their races.

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