Actually, I've never had a need for a trail-a-bike. Blame it on the fact that I don't have kids, nor do I want one. So why should I know about something that does not even enter my realm of reality?
However, I do know my brother was trying to figure out how to transport his younger kid around in the event of an emergency, and since he has my folder bike, my real concern is more about finding a trail a bike for a folder. I've not seen this before- just the one for the tandem and one I saw for Burley that was for regular bikes. Soooooo... having said that, I am still wondering if they have trail a bikes for folders, but I guess I shouldn't have asked here- I should have asked in the folding bike forum, or I should call the Bike Friday folks, since they know what can and can't be attached to their bikes. I've been to plenty of bike shops that claim such and such will work on the bike, then I buy such and such, only to find it doesn't work, then I have to go through the hassle of exchanging or losing out on the money because I can't return it.
Since no one knows specifically if the trail-a-bike will work for my Bike Friday, don't worry about answering my question. I should have researched it on my own.
Koffee