Crossmember

[jaybee]

Any thoughts of a frame center section like this Welder Series center section http://www.welderseries.com/blog/online-store/frame-center-section-universal/ As opposed to one in the style of this Art Morrison Max G chasis?  http://www.artmorrison.com/maxg.php

[enjenjo]

I think the Welder series is more suited to a pre 48 car, or a pickup a bit later. The Morrison one is more suited to a perimeter frame from the late 50s on.

[kb426]

Frank is correct. What are you trying to do?

[jaybee]

Thinking in terms of a 50s car. The second style looks like it adds a lot more weight. That's fine if it also adds a lot more stiffness. The first, by contrast, would be way easier to run exhaust through, but if it sacrifices a lot of strength in the process good planning can allow sufficient room for exhaust.

[jaybee]

Ummmm, and of course on a later car with significant driveshaft tunnel the shaft would run right through the top tubes of the first one...

I guess I didn't really express my thought very well. The point I was contemplating is if running what amounts to a second set of frame rails down the center of the car adds stiffness more than it adds weight.

[idrivejunk]

Small round tubes or big square- is that the question? I think the choice would be based on power level and intended usage if it were me. Big thick square tubes weigh more and take up more space and are probably more stiff. If modifying a stock frame on a mild build, I would say use whichever most closely resembles the stiffness of the existing rails. Either way is probably an improvement over stamped OE designs.

[enjenjo]

If you do a space frame type, out of multiple tubes with triangulation, you should get a good strength to weight ratio. A lot of it depends on what type of frame you are starting with.