Someone asked recently. l used  a tow ball mounted Thule rack with two adult bicycles on the motorway today for the first time.

Got an indicated 45mpg running at at 70 mph when I could. Without the bikes and rack I'd expect 50mpg plus from recent experiences. Not too bad,but felt the tail being wagged in the wind a couple of times although I do have the pukka wiring loom and allegedly the trailer stability system. But who knows?

Thought of the day,

If fitting Rear Bike Racks & more weight hang off the car and interrupting the air flow over the roof and behind the car & assisted in fuel economy or vehicle stability then they might be a standard fitment on cars.

If they were really good for economy then more would be better and all cars should tow a caravan all the time.

Not sure why you say that on this helpful forum. I'm just providing my experiences of the increase in fuel consumption. 5mpg drop is not bad compared to my previous experience with an Octavia diesel hatch.

Edited 24 June, 20178 yr by gregoir

Just messing.

I found that towball carriers don't make much difference to the fuel economy. The extra weight on the back creates swaying a little more than without but thats hardly surprising. You notice fuel economy drops and swaying more with 4 bikes on the back, family in the car and a loadspace full of camping gear for sure. Four bikes on the roof are worse than four on the back.

 

If the stability system kicks in, you are pushing it too far and out of control already.