So, coming from the US, I am having a difficult time locating a tow hitch mounted bike rack that clamps the tires and not the frame. Anyone have any experience, or recommendations? thanks!
Auxtail tow ball bike carrier clamps wheels only. I use my old Thule euroride 2 and I clamp the shock body instead of my carbon frame. As I mainly only have my bike I use the clamp for the 2nd bike to clamp the fork leg or csu as well (not the stanchions). You could also clamp the seat post.
Atera are pretty good. Although they still have an arm to clamp the frame this is much more about stabilising the bike rather than holding it firmly. The wheel tie-downs are a ratchet with a shaped block for the tyre. This holds the bike onto the carrier really firmly. For the top arm I have some extra blocks of LDPE foam to protect the frame.
Depending on what you need, they also do one that allows the back door of an estate or MPV/SUV to still be opened. I have one of these with 4 bikes and whilst it is tricky to slide it up and down without an extra person the likelihood is that if you have more than one bike, you will also have the extra muscle on hand.