Roof box - low drag

[Nemophilist]

We do a lot of travel by car and up u til now have been borrowing a roof box from a friend for each trip.

It’s been invaluable for space but it’s not very aerodynamic and it easily loses us 20mpg on long distance drives and causes awful wind noise above a certain speed

Im looking to buy my own but there are so many online it’s hard to know what’s best. I’d rather it not be too long as il still need access to the rear boot.

Can anyone recommend a good one?

[onlynik]

https://www.thule.com/en-gb/cargo-carrier/car-top-...

I really like this one

The also do one optimised for aerodynamics.

https://www.thule.com/en-gb/cargo-carrier/car-top-...

[GranpaB]

Wind noise will also come from your roof bars.

[thebraketester]

20mpg hit? So you went from what mpg to what mpg?

[RSbandit]

Got a Thule motion XL early 2022 for an Alps trip, got the aero bars that reduce wind noise also. On a long run I saw mpg drop from 40 to 30 with roofbox so it’s a noticeable difference but I tried to keep cruise at 70-75mph. Anything faster than that and the mpg would suffer more never mind that it gets a bit noisy.

[snowman99]

Have a big 500 litre Thule and I don’t think it made more than 10pm difference but I guess that increases exponentially with speed. 60-70mph ish.

[Nemophilist]

thebraketester said:

20mpg hit? So you went from what mpg to what mpg?

52-55mpg to about 32

(The box we borrow is very old, and as aerodynamic as a Brick)

Edited by Nemophilist on Sunday 1st January 20:12

[Nemophilist]

GranpaB said:

Wind noise will also come from your roof bars.

The bars do make a noise (I have noticed when driving with them on without the box)
I can’t improve them, they are the Thule aero ones in the shape of a teardrop

[Nemophilist]

RSbandit said:

Got a Thule motion XL early 2022 for an Alps trip, got the aero bars that reduce wind noise also. On a long run I saw mpg drop from 40 to 30 with roofbox so it’s a noticeable difference but I tried to keep cruise at 70-75mph. Anything faster than that and the mpg would suffer more never mind that it gets a bit noisy.

This sounds good to me!
Thanks for the recommendation

[Nemophilist]

onlynik said:

https://www.thule.com/en-gb/cargo-carrier/car-top-...

I really like this one

The also do one optimised for aerodynamics.

https://www.thule.com/en-gb/cargo-carrier/car-top-...

Wow those Vectors look pretty good. Bit more than I wanted to spend though.
The motion look a lot better than what we’ve been using though

[Gunk]

They’re all like a brick on the roof, useful but fugly. We used an old Mont Blanc box for about 10 years when the kids were little. Bought for £50 secondhand and then sold for about the same price 10 years later to an ex Le Mans driver!

It was well travelled!

[thebraketester]

Nemophilist said:

thebraketester said:

20mpg hit? So you went from what mpg to what mpg?

52-55mpg to about 32

(The box we borrow is very old, and as aerodynamic as a Brick)

Edited by Nemophilist on Sunday 1st January 20:12

Fair enough. We’ve got a Thule which is mega and I can’t say I noticed a huge difference in mpg. Certainly less than 10%. Looking to sell it as some point as we have now lost the use for it.

Edited by thebraketester on Sunday 1st January 20:25

[mr pg]

Take a look at Whispbar (now Yakima) aero roof bars. I couldn't detect any additional wind noise.

[the-norseman]

We have a Halfords one that came with our XC90 its quite large, looses us about 2mpg but is quite noisy.

[Nemophilist]

thebraketester said:

Nemophilist said:

thebraketester said:

20mpg hit? So you went from what mpg to what mpg?

52-55mpg to about 32

(The box we borrow is very old, and as aerodynamic as a Brick)

Edited by Nemophilist on Sunday 1st January 20:12

Fair enough. We’ve got a Thule which is mega and I can’t say I noticed a huge difference in mpg. Certainly less than 10%. Looking to sell it as some point as we have now lost the use for it.

Edited by thebraketester on Sunday 1st January 20:25

When are you looking to sell? Happen to be anywhere near Herts/Beds/Bucks?

[thebraketester]

Nemophilist said:

thebraketester said:

Nemophilist said:

thebraketester said:

20mpg hit? So you went from what mpg to what mpg?

52-55mpg to about 32

(The box we borrow is very old, and as aerodynamic as a Brick)

Edited by Nemophilist on Sunday 1st January 20:12

Fair enough. We’ve got a Thule which is mega and I can’t say I noticed a huge difference in mpg. Certainly less than 10%. Looking to sell it as some point as we have now lost the use for it.

Edited by thebraketester on Sunday 1st January 20:25

When are you looking to sell? Happen to be anywhere near Herts/Beds/Bucks?

Check your emails

[Nemophilist]

thebraketester said:

Nemophilist said:

thebraketester said:

Nemophilist said:

thebraketester said:

20mpg hit? So you went from what mpg to what mpg?

52-55mpg to about 32

(The box we borrow is very old, and as aerodynamic as a Brick)

Edited by Nemophilist on Sunday 1st January 20:12

Fair enough. We’ve got a Thule which is mega and I can’t say I noticed a huge difference in mpg. Certainly less than 10%. Looking to sell it as some point as we have now lost the use for it.

Edited by thebraketester on Sunday 1st January 20:25

When are you looking to sell? Happen to be anywhere near Herts/Beds/Bucks?

Thanks! I’ve responded

Check your emails

[MBVitoria]

I've got a Thule Alpine 700 which is long and slender like the one above on the BMW and it only loses about 2-3mpg on top of a big camper van.

[vikingaero]

Depends on the car and roofbox!

A small car with a large roofbox will have a horrific effect on MPG because of the huge increase in frontal area. The same roofbox on a large car will have a lesser effect.

I had a medium sized 320 litre Thule/ It was pretty swoopy and aero looking. MPG hit on larger cars was around 2 MPG.

Some people have roofboxes that resemble bricks.

[Squadrone Rosso]

We’ve got a Euro Car Parts cheap box on the RAV4.

Lost maybe 3 mpg on our summer trip to France but put that down to higher motor way speeds in addition to being a fully packed car.

I intend to upgrade to a Thule / Halfords Advanced before the summer but mainly due to the dual side box opening & a better mounting system.