I installed a 1.25 inch hitch on my 2012 Prius and purchased a Thule Helium back rack for 2 bikes. I made a 3000 mile trip with two bikes mounted on the back and averaged 40mpg for the trip. I had done a previous trip of 1800 miles with no rack or bike and averaged 54mpg. Much of the 3000 mile trip was done in 40-45 F weather at 70mph while the 1800 mile trip was at 60-65F at 55mph speeds. So its hard to separate all of these variables. I sensed the bike rack was pulling gas mileage down by about 8miles/gallon. Has anyone had similar experience?
Yes. I have a Helium 3 on a 2 inch hitch. I haven't yet used it enough at highway speed to accurately characterize the mpg loss, but it is similar to your 8 mpg figure. Bikes still go inside my car when cargo capacity allows. But when supporting cycling events, or when the spouse needs to be able to do the loading, or when my aging back hurts, the rack is used.
when I drive long distance on the highway I always get around 42mpg simply because im doing 85mph. When im local and have my bike i still get less maybe not as bad but its because the wheels stick out on both ends causing resistance.
