Motoring Discussion > Fuel consumption with bike carrier attached Miscellaneous
Thread Author: BobbyG Replies: 9

 Fuel consumption with bike carrier attached - BobbyG
Well after long deliberation we decided to bring the 4 bikes on holiday as, even though it would reduce fuel consumption, it would still be cheaper than hiring bikes at Center Parcs. So 4 bikes on the roofbars of my Seat Altea XL. Usual fuel consumption for a journey like this without bikes is 40-42mpg.

First leg was from Lanarkshire to Harrogate. Due to the missus taking so long to pack my bag, we were a bit late in leaving so had to make decent progress, had cruise control set at 72mph GPS speed and I was shocked to discover the average consumption when I arrived in Harrogate had been ....... 27.1mpg. OK, it was also quite windy but ouch!

Second leg from Harrogate to Center Parcs was more relaxed, no rush so didn't go above 60mph, plus buser roads meant I managed to get 38.7mpg for that leg of the journey.

Have been to Center Parcs several times and have enjoyed the relaxed secure atmosphere. Was a bit offputting receiving notices re boike thefts, make sure they are chained up or even better, put in your chalet at night and also don't leave bike racks on the rear or roof of your car! I know that in one of the other CP sites recently there had been a huge bike theft problem but not this one in Sherwood Forest.

Next leg of journey on Friday is a relaxed drive down to Bishops Stortford and then over to Newquay on Sunday - expect that to be another 26mpg job!

And by the way, for anyone coming to this CP, there is now a big Tesco built a coupl eof miles away that you can fill up with food and drink before arriving! You don't want to be paying the prices they charge inside the park!
 Fuel consumption with bike carrier attached - Bromptonaut
Interesting post Bobby. As mentioned elsewhere we took four bikes to the Hebrides atop our Xantia last month. It's pretty much an annual trip and the journey north relaxed & very much part of the holiday. Coming home is a chore and we just want to make progress to home & bed.

Northbound we went with the flow, got caught in an 80 mile jam from Stoke to Preston and generally enjoyed ourselves all the way; got about he usual 40mpg.

Homebound is OK 'til Scotland's central belt after which it's just a motorway thrash all the way to M1/J16; once on the M80 pegged the beast at an indicated 85. Normally I'd get home on the tankful uplifted at Morrisons in Fort William. This time I had to top up at Keele and suspect I was barely managing 35 to the gallon.

Lesson is that bike massively increase the drag factor.
 Fuel consumption with bike carrier attached - idle_chatterer
I wonder whether it's having 4 bikes which increases the drag so dramatically ?

I have tried 3 approaches:

2 bikes on roof, around 42mpg from my 330d touring, sticking to 70mph
2 on roof, 2 on tow-bar mounted carrier, drops to around 40mpg, again at around 70mph
4 on carriers mounted on top of trailer (plus camping gear in trailer), 44mpg but sticking to a legal 60mph. N.B I have a stable Brenderup trailer and it's well worth the extra money if you want to go far with the thing imho.

Cruising at 75mph I get around 50mpg without roof bars / carriers on.

Last time we went to CP is was in the snow at New Year, bikes got covered in salt crud en-route which did them no good at all, mountain bikes in the snow were a blast though !
 Fuel consumption with bike carrier attached - FotheringtonTomas
Your bicycles are much less of a factor in your fuel consumption figures than is your speed.
 Fuel consumption with bike carrier attached - Zero
>> Your bicycles are much less of a factor in your fuel consumption figures than is
>> your speed.

your bycles are very much a factor increasingly with speed. In short higher speeds and large drag factor dont mix.
 Fuel consumption with bike carrier attached - idle_chatterer
>> your bycles are very much a factor increasingly with speed. In short higher speeds and
>> large drag factor dont mix.
>>

Agreed, which is precisely why I go a little slower, IIRC the drag increases with the square of the speed ? It's also psychologically better (for me), I cringe when I see people stream by at 80+ mph with their bikes precariously wobbling - especially on those hatch-back wrecking clip on carriers.

A bike is fairly un-aerodynamic and putting 4 aloft obviously increases drag, however I wonder whether there are further effects from vortices which aren't so pronounced when you only have 2 bikes spaced apart on the roof ? Of course, it doesn't really matter, you've got to carry the things some-how so just go slower or buy extra fuel.....
Last edited by: idle_chatterer on Tue 29 Jun 10 at 23:06
 Fuel consumption with bike carrier attached - FotheringtonTomas
Perhaps you misunderstood what I wrote. If so, never mind.
 Fuel consumption with bike carrier attached - Bromptonaut
My experience/understanding is that the bikes on the roof make sure the speed/drag equation is crystal clear!!!
 Fuel consumption with bike carrier attached - Westpig
I've managed to get my wife's car consumption down to 28mpg with a monster Thule roofbox on board and driving at speed overnight (2.0 turbo diesel Ford engine in Jag X Type est)...yet coming out of a services after a fill up and having to do 52mph for quite a while in roadworks, it made very little difference to the usual mpg.
 Fuel consumption with bike carrier attached - Fenlander
I commented a few weeks back after our hols with 4 bikes on the C5 roof...... fuel consumption was down at least 12mpg (to 42mpg) at modest speeds up to motorway limit but the saving over hiring bikes paid for the carriers and fuel this time and next trip we'll be well in profit so a good result.
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