The Yakima Tube Top adapts bike frames without top tubes so they fit Yakima ROC or GetAway bike mounts. It's a clever little invention! The Tube Top creates a top tube for any bike that doesn't have one (children's, women's or Y-frame style bikes).
I mean seriously heavy. It does the job but I doubt that it had to weigh that much. It would be better if there was some way to fix the length so it wouldn't move after it is attached. Not that that affected the end result but it was a bit annoying.
It is always a little unnerving to throw your multi-thousand dollar investment onto a $35.00 piece of plastic/composite/whatever, especially when the maiden voyage involves 80mph speeds on a windy freeway. However, this little bar got the job done! It does hold the top tube of my bike a little too close to the rack arms itself (has caused some scuffs to my steed), which I don't like..this is probably the only reason I gave it a 4/5. That might be my racks fault though, as it is a home made hitch rack and isn't designed as well as Yakima or Thule makes them. There is no locking mechanism on the telescoping part of the tube top, but it stays steady somehow. There are pins on the ends which keeps your seat post and handle bars from slipping out the side. I have read a few reviews online which say that you need to make sure your seat post is all the way tightened, or else your bike might fall off the rack. I have kept mine tight so far and have had no problems whatsoever, but for everyone reading this..keep that fact in mind.
P.S. my horizontal top tube length is 22.5 inches, and this fits fine with tons of room to spare.
I shopped all around the net and couldn't find this item at a lower cost than BCS. When it arrived I was stunned at the quality of materials and workmanship! This is one tough adapter. Its cost is justified. I tried it on my son's 20" bike -- a V frame, and it fit wonderfully. It telescopes and should fit any frame you can throw at it.