Asymmetrical roll bar

B

BBarton

New member
OK...maybe a dumb question. I have raced for years in SRF3 and am now building an open TR6 for historic and maybe F prod. Why are people putting asymmetrical roll bars in their open cars? Why not a full width main hoop?
 
Some think it is more aerodynamic, but with the way the current rules are written, I would think the difference is minimal. You also need to consider whether or not you use a high front hoop or a low one.
 
Round tubes SUCK for aero. You cut a diagonal instead and you're taking away 2/7ths of that 3-4-5 right-triangle aero drag.

"Significant"? 🤷‍♂️ But it's not zero.
 
I've run both styles of roll bars over the years but one of my cars has an asymetrical rear hoop but with a narrow matching front hoop tied to it with fore and aft tubes. It must work because the former owner/builder got the car upside down twice without hurting the driver or the hoops. I agree that it doesn't do much for aerodynamics but it does cut down the weight. Like Don said, every little bit helps. Heard that Joe Hafaker suggests a slight nose low car to improve the aerodynamics. For me it's all about what what works for crash protection.
 
In my Turbo jetta chumpcar ( Roadtster, cuz light weight helps things last ) . I doubled the torque over the carb NA version and only picked up 3 mph . I looked into aero auto and came across a bunch of hypermile stuff. They did a lot of coast down aero drag testing.
I had access to my local airport where my Ultralight was parked. 7000 ft old runway.
I stablized the tires at 40 and filled the fuel every other pass. and started measuring coast down from 70-50 . It had 2 seats at this point , the streamers were every where.
Removed the pass seat, front hoop mounted mirror, tailights, adding a small fairing up over the rear tailight panel. Picked up a lot, enough to add about 5 mph at the end of the sebring back straight and another 2 seconds laptime .
The seat made such a huge change that I put it back in and re-tested.

I learned a lot about aero , tire s, tire pressure, and camber thrust, etc.

 
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