My first DIY sim racing rig design back long time ago. The goal was to make it with as little profiles as possible while still being very rigid and having all the needed extras. The original on the pictures has somewhat different setup, but it was made so long time ago.

I simplified the design further and this is the outcome - the 5780-LT DIY sim racing rig!

The rig can be easily extended in future with much more advanced features even with motion! All the parts are meant to be reused with little addition of extra profiles to achieve this extension. Current built is as simple as possible. Parts list include only the main rig BOM, you can pair it with whatever extension you favor. I have linked above the pedal plate, wheelbase mount and shifter arm featured here. Visit the corresponding project page for BOM. I will try to keep all documentation modular so you can select which designs to pair easily.

Main features of the 5780-LT sim rig:

• Subframe length is 1300mm - roomy enough to accommodate any driver/equipment combo
• Distance between subframe sides is 500mm - one of the most common sizes
• Vertical wheelbase posts use metal plate T-Connect 80x160 - in all my variations this proved to be the most stable one, also easiest for installation
• Vertical WB posts are outside the rig providing secure interface with the subframe for extra rigidity
• The 500mm spacing + 10mm T-Connect give you 600mm between vertical supports - very common spacing which gives you option to extend in future with brand accessories like wheelbase mounts, monitor stands, etc.
• Subframe is built with double corner brackets as they provide better stability and easier alignment. The ones I used are from Trakracer, but there are alternatives. 
• Opted for outside backplate mounting as it is easier to align with the double brackets, also looks nicer. If double brackets are hard to obtain it is fine to substitute with whatever single ones you find, but be careful with alignment.

Despite very simple designed, the rig is quite stable and rigid, it is capable of handling wheelbases with high torque when paired with my side mounts. It is also strong enough to support integrated monitor mount.

Adding damping feet is strongly recommended. The ones I designed use heavy duty machinery adjustable feet and were keeping very well all vibrations coming from wheelbase/shakers inside the rig.

If you need the source file - as usual hit the "Remix" button above.