Yes, the aluminum tube is that flimsy. I've had the long dometics over 20' and just the bouncing going down the road caused them to start sagging in the middle over time. Didn't affect the function, just not as appealing to the eye. Kind of a judgement call or matter of preference. I don't have the cradle support on ours now, but it's only 18'.
John and Rebecca Dickson
Emma-8 / Little John-5 / Iva-1+
2013 Ford F-350 Lariat FX4, CC LB PSD, DRW
2015 Jayco Jay Flight 28BHBE (#8)