Bike carriers and mpg

[Banjo]

Read an article about bike carriers on cars. Roof ones drop your mpg by about 6 or 7 mpg rear ones by about 4 mpg .Would add up over a lot of miles in a year,

I normally put my bike in the back of our Astra with rear seat folded and front wheel off. Not an option if more than 2 of you travelling.

 

[Gixxerman]

Fine if you have a hatchback. I have a coupe so the option is right out. I was toying with getting some sort of rear bke carrier, but I cannot find one that fits in such a way that it won't damage my expensive paintwork. So it would have to be a roof rack one. At present I have to use trains to get to meets, or rely one other mates with vans etc.

Top Gear did a similar exercise of driving from (I think) London to Endinburgh in 2 identical cars, one with a lawn chair on the roof rack and one without (as a control).
They worked out that the extra fuel used due to the extra drag paid for the price of the chair many times over, and it would have been cheaper to simply throw the chair away and buy a new one.

 

[lulubel]

I had a towbar put on our car so we can use a towbar mounted rack. We had used a hatchback high mount one before that, but it was horrible, and didn't feel safe, and I didn't like the idea of putting them on the roof where I couldn't keep an eye on them (and might forget they were there if I went under something low).

 

[gaz]

Top Gear did a similar exercise of driving from (I think) London to Endinburgh in 2 identical cars, one with a lawn chair on the roof rack and one without (as a control).
They worked out that the extra fuel used due to the extra drag paid for the price of the chair many times over, and it would have been cheaper to simply throw the chair away and buy a new one.

They didn't do that. The drove from london to endinburgh and back with one tank of fuel. They calculated that if they had a lawn chair on the top it would take up x amount more fuel per mile.

 

[Gixxerman]

They didn't do that. The drove from london to endinburgh and back with one tank of fuel. They calculated that if they had a lawn chair on the top it would take up x amount more fuel per mile.

Ok thanks for putting me right Gaz. I knew it was something along those lines but I couldn't remember exactly, it was a long time ago and I have had a lot of slleps since then!

 

[Banjo]

I had a towbar put on our car so we can use a towbar mounted rack. We had used a hatchback high mount one before that, but it was horrible, and didn't feel safe, and I didn't like the idea of putting them on the roof where I couldn't keep an eye on them (and might forget they were there if I went under something low).

I very nearly drove under a height restriction barrier entering a supermarket in Macclesfield area.
Luckilly my 14 yr old son reminded me at the last minute we had two bikes on the roof.

 

[Gixxerman]

I very nearly drove under a height restriction barrier entering a supermarket in Macclesfield area.
Luckilly my 14 yr old son reminded me at the last minute we had two bikes on the roof.

I remember seeing something like that on one of those "you've been framed" type programs. It pushed the back wheel of the bike through the rear window of the car. I am sure someone will no doubt find the video somewhere.

 

[Nebulous]

I really don't see that. We used to take off the roof bars - with roof box and bike carrier, but now we tend to leave them on. I have greatly cut down my miles though, and try to drive more slowly than I used to.

 

[Crackle]

With four bikes on top I get 5mpg less. With the roofbars alone, there's no appreciable difference in mpg. It makes more difference if I turn the aircon off.

If I did more motorway driving I would take the carriers and bars off but I don't do much.

 

[Glover Fan]

I normally put my bike in the back of our Astra with rear seat folded and front wheel off. Not an option if more than 2 of you travelling.

+1 I have a vw golf mk5 and can fit my road bike in without doing anything to the wheels/seat.

 

[corshamjim]

With my roof bars on and bike on the roof, my little Aygo still uses a whole lot less fuel than most other cars on the road - especially as I don't drive it at all fast. If I were using the rack a lot, I wouldn't bother ever removing the bars. As it is, I don't expect to need the rack until August so I've removed them for the time being.

 

[Cubist]

Towbar mounted bike rack on my Discovery appears to improve economy. I wonder whether it's the fact that the bikes disturb the sucking effect of the slab back end?

 

[asterix]

Towbar mounted bike rack on my Discovery appears to improve economy. I wonder whether it's the fact that the bikes disturb the sucking effect of the slab back end?

Get thee behind me Satan!

 

[Norm]

Towbar mounted bike rack on my Discovery appears to improve economy. I wonder whether it's the fact that the bikes disturb the sucking effect of the slab back end?

Unlikely, as the sharp cut-off is quite a good shape for aerodynamic efficiency.

However, you might be doing the same as I do, and driving slower with the bikes on that back. Whilst they aren't technically a trailer, I do tend to stick closer to the trailer speed limits when carrying the bikes, and dropping the speed from **ahem** 70mph to 60mph is more than enough to offset any extra drag which they do cause.

 

[Bicycle]

I have roof bars. I have no idea what the MPG impact is.

Upsides:

Hatch is easy to open.
I don't need a trailer board to replicate an obscured number plate.
I can use the roof-mount on both cars and it survives a change of car.
I can carry 3 bicycles (or 2 and a biggish roofbox).
The car is no wider.
Visibility is not affected.
None of those unsightly webbing straps holding everything together.


Downsides:

Drive-through takeaway restaurants. Bent handlebar. Oops!

Where I can, I carry bicycles inside the car. Most people I know prefer a tail-mounted rack, but I am happy with roof-mount. The MPG thing never really occurred to me.

A car is a fiendishly expensive toy anyway and I think we have too many of them in our family... But they are just so useful when you want to get somewhere.