Square tube lower frame layer?

[standfast]

I was thinking about the direction of loading on the lower frame layer and started to wonder why square tubing wasn't used here more often. It seems like it would be stronger and more appropriate given the load directions. I see some TT's being built that the lower frame layer are basically boxed structures. Obviously a roll cage needs to be round with the multi directional loading but it seems as a lower frame layer could benefit from the use of a square structure. Kinda like a boxed vs. round suspension arm. Single direction loading makes the box structure more preferable. I would imagine tube direction changes would not be made with bends but cut angles. Cut the appropriate angles, cap the ends and weld them together and gusset accordingly. Just curious what others though about this...

[partybarge_pilot]

Look at Pro-2 and Prolite standardized chassis.

[CRAIG_HALL]

And on a smaller scale, here on the Full Potential superlites (lucas series trucks)

[Scott_F]

I was thinking about the direction of loading on the lower frame layer and started to wonder why square tubing wasn't used here more often. It seems like it would be stronger and more appropriate given the load directions. I see some TT's being built that the lower frame layer are basically boxed structures. Obviously a roll cage needs to be round with the multi directional loading but it seems as a lower frame layer could benefit from the use of a square structure. Kinda like a boxed vs. round suspension arm. Single direction loading makes the box structure more preferable. I would imagine tube direction changes would not be made with bends but cut angles. Cut the appropriate angles, cap the ends and weld them together and gusset accordingly. Just curious what others though about this...

I agree 100% and this is how I designed my chassis.

[joe1369]

I agree 100% and this is how I designed my chassis.

This opens up whole different group of questions, Is there chromo available?? If no what size????? 2x2 x .120, 2x3 .120 ??? or thinner????:D

[CRAIG_HALL]

This opens up whole different group of questions, Is there chromo available?? If no what size????? 2x2 x .120, 2x3 .120 ??? or thinner????:D

Caltime will have the most common sizes (1.5 & 1.75 square)easily over 20$ foot though. Other sizes check with FACTORY STEEL in Detroit.

[Scott_F]

This opens up whole different group of questions, Is there chromo available?? If no what size????? 2x2 x .120, 2x3 .120 ??? or thinner????:D

The CORR Pro2 and Pro4 spec chassis use 2x3x.120 mild tubing. 4130 is available in 1.5" square tubing, but I have not seen bigger sizes. The high end Y shaped chassis are laser cut from 4130 plate and welded into box sections.

[CRAIG_HALL]

I get both 1.5 & 1.75 X .120 from Caltime regularly. 2"x3" (in 4130) was only available in .083 when I spoke with Factory steel

[D-rek]

I have a Full Potential 4 seater and the floor frame is 2x3 structural steel. The car has been very strong and performed very well. In vertical sheer a piece of 2x3 has a moment of inertia(strength measurement) of at least 4 times what of 2" round tubing has.

[atomicjoe23]

The high end Y shaped chassis are laser cut from 4130 plate and welded into box sections.

These Y-shaped frames are so cool. . .I asked around and what I heard back from some was that it was .120" 4130 plate for the main structure and 0.090" plate for the reinforcement pieces. . .

[spi6616]

I remember a time way back when that you would strung up by the thumbs to be talking of sq.or rec. tubing in an off road car. I for one don't like the new boxed chassis design as is one of the well known and highly successful TT manufacturer here in PHX concurs on no boxed chassis's.
I don't believe there is anything wrong with them I'm just OLD- SCHOOL!
I'll someday adjust.

[atomicjoe23]

The box-sectioned frames that are made from plate are definitely WAY more labor intensive ($$$) than a round tube frame woudl be for the same thing. . .that would be the biggest downside in my opinion, but they sure do look trick and there is more room for creativity as well. . .