I don't know... I'm just not sold. I may have a bias. We use a BOB Yak. Why does a Travoy cost so much? As a previous poster already noted, its just a small appliance hand-cart (or large luggage roller) and those can be had for ~$50. A BOB Yak is pretty expensive too and recent copies of it sell for less than $80 (with stuff sack!) vs. $300 for the genuine article, but I digress. At least a Yak puts the load down low and it is hard to argue that it is a LOT more aerodynamic than a Travoy. And please do not dismiss the importance of aero. ALL your work on a bike is caused by the air molecules piling up in front of you as you move forward. ALL. Anything you can do to reduce the drag of air resistance becomes extra speed or endurance. Can you really say you don't need another few mph? Using a Travoy as a shopping trolley is also a massive fail. It is not self stable like a real shopping trolley. It falls right down to the ground when you let the handle go. With any significant load in it... you're not going to like the handling. If it had some kind of waist or shoulder harness so you could pull it behind you while walking... I thought I saw such a thing once and I have called every outdoor outfitter in existence asking them if such a thing exists and to a one they say "no, but go ahead and invent it, it sounds like something we would sell if we had any". FWIW.

H