My dealer gave me a 4000 lb Equal-i-zer with my Roo 19. When I put the Roo 19 info into Equai-i-zer's calculator (4770 GVWR, 500 lb tongue) it says it should be a 6000 lb. When I add 100 lbs for my bikes on the back, it says 6000 lb, but says, "However, you appear to be close to exceeding the maximum weight rating of the hitch. You may want to consider a heavier hitch, especially if the amount of cargo you are carrying increases."
All that being said, though, I haven't had any issues with my 4000 lb hitch. It seems just fine. And I can really tell the difference with the bars installed vs just the ball.
1988 Coleman Sequoia - popup (1987-2007)
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10