Jagee - I went down and checked my Twenty. It stands because of the really uneven floor in my (unfinished) basement. I tried standing it up in a flat region, and it would not. I am a creature of habit, and I was placing it against a slightly raised portion of the floor. My rack is also slightly curved, but the uneven floor allows it to rest evenly.
So, actually it will not stand on the rack and wheel, except in exceptional circumstances.