Huh? Hitches are typically rated for a tongue load 1/10 of the towing limit, like 500 and 5000 lbs for a puny class three and 1000/10000 for a class IV. The integral rear bumper hitch on many compact pickups is rated for 300/3000 lbs. My boat or box trailer puts way more load on my hitch than any bike rack would.

Be that as it may... I have hitch rack that hangs two bikes from their top tubes which works well, but for our new carbon bikes just got a Saris Thelma hitch rack which holds the bikes by the wheels. I haven't had the opportunity to use it much but so far, I'm happy with it.