gussets

[BALS aSALT]

so i was just wondering on scta rules stating that i need 4" of gussets on main hoop junctions. does that mean 4" total length by measuring the length of each welded side or do they want to see a gusset that is 4" in length on each side? i've got some pics of cars and the gussets don't seem that big. i tried a 4" piece on each side and boy is it a big ugly. . hate to do that to my beautiful cage. i have some real nice prefab dragrace gussets that are almost 2" each side and look really good cosmetically and structurally. do you think that those gussets and my cage itself will pass?

[Cajun Kid]

two 2" gussets = 0ne 4"    just another question ?

[Rex Schimmer]

The rule book says "4 inches per side" which I think means that if the gusset is a right triangle you have two 4 inch sides and the long side is 5.65 inches long.

There has been a number of discussion on this forum regarding this requirement and it appears to me that the reasoning for this is based upon some SCTA after crash inspection information and experience and they are pretty adamant about having gussets although I have seen many cars use heavy wall 1 inch tubing for the gussets also and they have been approved. It always looked to me as a patch to cover up an improperly designed tube joint, but you have to have them.

Rex

[johnneilson]

The rule book says "4 inches per side" which I think means that if the gusset is a right triangle you have two 4 inch sides and the long side is 5.65 inches long.

There has been a number of discussion on this forum regarding this requirement and it appears to me that the reasoning for this is based upon some SCTA after crash inspection information and experience and they are pretty adamant about having gussets although I have seen many cars use heavy wall 1 inch tubing for the gussets also and they have been approved. It always looked to me as a patch to cover up an improperly designed tube joint, but you have to have them.

Rex

I read the rule the same way, 4" of attached dimension per tube.
As I understand the reason, a few years ago, someone added the required heavier top cage to a thinner wall chassis without any reinforcements. During a roll over, the more rigid top section tore itself loose from the chassis.
I can see the merit of this gusset in an application where the top cage is dissimilar material to chassis.
It is also my opinion that the formed gussets (wrap type) would be stronger and distribute the load over a larger area with more uniformity, just an opinion.

Rumor has it that some extremist has tortured the rule into making the gusset so large as to create a airfoil and downforce. This I want to see........

John

[JoshH]

John,

Thanks for including the history on the rule; I've often wondered about that. I really wish this rule would be amended to allow either plate or tubular gussets.

Josh

[Seldom Seen Slim]

Josh, I'll say it before someone else beats me to it:  There's always the rule change process.  Go ffor it if you're sincere about wishing to allow tube gussets.

[JoshH]

I was hearing your future comment echo in my head while I was typing....

[jww36]

BALSaSALT;
I'm a fabricator and in the process of building a gas roadster. Like you, the Gussets as mentioned in the rule book are pretty ugly and I thought there must be a better way to re-inforce this roll cage junction then a simple steel strap welded to the outside of the tube. I found some tubular gussets that not only look better but provide much more strength.  

If you are interested, you can email me @ Redhunter1936@aol.com.

[Dynoroom]

As has been stated before the rule book only gives you an example. Posted below is a cage with tubular gussets & another with plates.
Yes the tubular one should have more tubes. oops!   

[NathanStewart]

Go ffor it if you're sincere about wishing to allow tube gussets.

I'll second anyone who proposes this. 

[jimmy six]

One small point to this; if your roll cage tubes extend to the main frame in a single piece of tubing no gussets have been required. The requirment for gussets are for the shoulder bar type cage.

In addition to the reason for the rule I believe the car in question had it's cage structure replaced twice and there was some conjecture that the metal was fatigued and brittle. As with most rules for safety; a major accident, injury or fatality brings on a change that may or may not have been over looked.

[Rex Schimmer]

The Specter streamliner, formally Junior Kurtz's and originally built and ran by Roy Fjastad (Roy I cannot ever remember how to spell your name!! please forgive me.) uses tube gussets and this car has ran over 400.

I really like the gussets that Mike has shown on Seth's car and also note the way that the main cage loops have a load path directly into the adjacent structure. No tube offset BS each tube aligns with more tubes that spread the load through out the chassis. Well done!

Rex

[Model T Steve]

Remember- They are supposed to be stitch welded.

[BALS aSALT]

well i've made up my mind. i'll be using 1" tube as well as the plate system. i'll just have to spend some time making them look good.

[Cajun Kid]

I agree with the tubular gussets... I used  1" x .120 DOM tubing for my gussets. (at every tube junction in the entire cage)

Charles