In the 2008 rule book it specifically states that at the intersection of the roll bar hoops and shoulder rail
that .125 X 4" braces must be used(pg 25). However in several pictures from 2008 Bonneville I see small diameter knee braces being used.What dia. length and wall thickness knee braces must be used.
I use 1.0" x .125 tubing. You will pass tech with them.
joe
:? At the risk of sounding totally stupid...What is a "knee brace" :|
Terry :cheers:
Terry,
What I call the Knee Brace is a Knee Bar, it runs from each side of the car under the dash/above the knees and attaches to the vertical "A" Pillar cage bars.
Here is a pic of mine during the upfit.
Hope you can see it and this helps.
Charles
(http://i261.photobucket.com/albums/ii43/cajunkid5690/IMG_0410.jpg)
Believe the referenced "knee brace/bar" is an alternative to the required gussets at the tube junctions of roll bars and hoops at the shoulder bar junction as in a lakester or roadster cage. 2008 SCTA rule book figure 2 & 3 page 25 and 2008 ECTA rule book figure 2,3, & 4 page 20.
Ed
:? Yes, that is kinda what I thought, but how long does the brace have to be? And, does it have to be welded in at a 45 deg angle to the vertical role bar/cage and the horizontal frame rail (assuming that the rollbar/cage is perpendicular to the frame rail)? :? :?
I guess I am confused. I am figuring that a knee brace is different from the gussets required. I have a complete continuous front hoop right behind my firewall with an "X" welded in the center of the same dia tubing as my cage, which I guess would take place of the knee brace. My shoulder bar also has the required gussets made of .125 X 4" wide welded shoulder bar to my uprights as required by SCTA 3.B.1 "Roll Cage".
FYI....to me, I would be concerned that the "knee brace" would not be tough enough to keep the tubing uprights straight in case of a side impact roll over especially if they have additional bends in them, which would make them weaker in compression. That is why I have the "X" welded in my front hoop (right behind the firewall) plus another right behind my seat. For more strength, I have another "angeled" upright (V-Shape with the bottom of the "V" welded to a plate that bolts to my frame) on the passenger side of my car and connects to the back uprights (that go over my head) and the other leg is welded on to the shoulder bar where it intersects with the with my main front "overhead" hoop. What concerns me the most is that with the roll cage and seating being to the extreme left on a street roadster, there is very little area for additional uprights to the drivers side of the car, because of the positioning of the roll cage, but alot of room to the passenger side of the car for additional roll cage support, which I have used for additonal support. I have raced for many years in both drag racing and circle track, and I place a high value on side and front impact protection to keep my cages from caving in or moving under extreme circumstances.