When I bought the Trek 700 bike with the women’s style frame for my wife, I never really considered the problem of mounting it on the bike rack. Even mounting it on my bike repair stand has been a pain. It doesn’t have a horizontal top tube.
I started searching for a solution and found that they make some called a bike frame adapter. It looks like it connects from the handlebar stem, and to the seat post. It basic creates a temporary top tube that will give you something to hang on the bike rack.
Well, find that something exists is half the battle. I started searching around. I found a couple on Amazon. It looks like the average price for these frame adapters is about $20-$25. I found one made by Saris, and another made by Thule. I ended up ordering the Thule 982 Bicycle Frame Adapter. It cost a few bucks more than the Saris, but since it cost $25 or more (it cost $25 even), I can get free shipping. There were some other frame adapters as well, but by companies I have never heard of. I have heard of Thule, and they make quality bike racks. So I figure their frame adaptor is probably solid too. I sure don’t want a bike falling of a bike rack while cruising down the road!