I have this vague recollection from many years ago that the Sports Car Club of America (SCCA) had a racing class for 3 wheel vehicles that had the single wheel

I have this vague recollection from many years ago that the Sports Car Club of America (SCCA) had a racing class for 3 wheel vehicles that had the single wheel in the back. They were typically powered by motorcycle engines and they looked really cool! I don't remember exactly when it happened, but I think SCCA banned all 3 wheel racing vehicles some time back. I think it was because 3 wheel vehicles with the single wheel in the front are inherently less stable. It's a shame because that class was less expensive to compete in, and the cars looked great.