I had originally got the kayak trailer for two main reasons; firstly to stop having to lift the heavy kayaks up high thereby risking shoulder injury, and secondly to decrease wind drag on the car to increase fuel economy. This winter I had to switch back to the roof rack as I was getting the kayaks covered in road salt and muck every time I was going to a pool session, and eventually the second garage where the kayak tralier was stored got blocked by mounds of snow.
The past months I have been measuring the impact of having Thule 835XTR Hull-a-port permanently mounted to the Volvo’s aero bars. I discovered to my horror that I was getting roughly 75 miles less per 15 gallon tank of gas, this represents a 19.7% decrease in miles per gallon! Clearly not a very green option. Today I switched to use a pair of Thule 878XT Set-to-Go these seem to have a much lower profile and reduced frontal area so I hope to see an increase in fuel economy as a result. I will post what I find out in a few weeks once I have burned through a few tanks of gas.
If things do not improve I will go back to the trailer and use the sock and just wash it regularly.