I've had a Thule tow-bar (9403) rack for years, they are very good - plus my riding pal has one of the more expensive models (946) - even better.

With the roof ones there is a quite large fuel cost, especially at speed and the usually the need to take the wheels off and the fact that you must remember they are there for height restrictions...

Any bike that falls off a tow-bar rack, is usually down to user-error...  been there

Arry Monk - Try wrapping a small section of an old lizard skin around the downtube where the clamps fit. This saves on scrathing and wear marks on the frame. Make sure after a ride that you clean the frame or behind the skin first. Ive been doning this for years with my Thule system on all 3 bikes and it certainly helps.

If you've got a nice (£2500) bike then go the whole hog and get a

They have them here. But better to call and discuss discount!