Bike carriers and mpg

[Cubist]

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. .

Not bloody likely. In fact I speed up, swerve about, pass as close to cyclists as possible and have a blatant disregard for the safety of others, whilst simultaneously murdering small furry woodland creatures and arranging for swathes of rainforest to be slashed and burned from my Gucci handheld mobile, given to me by my children Imogen and Tarquin.

Apparently.

 

[Angelfishsolo]

Good man. Glad to see you are living up-to the image of 4x4 drivers

Not bloody likely. In fact I speed up, swerve about, pass as close to cyclists as possible and have a blatant disregard for the safety of others, whilst simultaneously murdering small furry woodland creatures and arranging for swathes of rainforest to be slashed and burned from my Gucci handheld mobile, given to me by my children Imogen and Tarquin.

Apparently.

 

[Norm]

Not bloody likely. In fact I speed up, swerve about, pass as close to cyclists as possible and have a blatant disregard for the safety of others, whilst simultaneously murdering small furry woodland creatures and arranging for swathes of rainforest to be slashed and burned from my Gucci handheld mobile, given to me by my children Imogen and Tarquin.

Apparently.

I think you passed me a few days ago, only you were in an Audi.

What a very strange concept, someone in a 4x4 considering fuel consumption, surely the whole ethos of 4x4 ownership is "I don't give a sh*t about anything other than myself"

My concern is usually "What's going to fall off next and will I need to stop to pick it up or will it still be there when I drive back later".

 

[lulubel]

What a very strange concept, someone in a 4x4 considering fuel consumption, surely the whole ethos of 4x4 ownership is "I don't give a sh*t about anything other than myself"

Sometimes it's simply a case of, "I'd like to be able to get up the - so called - road to my house without having to go back and pick up my exhaust every time."

 

[Cubist]

What a very strange concept, someone in a 4x4 considering fuel consumption, surely the whole ethos of 4x4 ownership is "I don't give a sh*t about anything other than myself"

Haven't we done all this bollocks somewhere else? If you want to pick fights **** off and do it somewhere else. ****

 

[al-fresco]

I fitted roof bars and a Thule carrier. I pay close attention to my fuel consumption and I haven't been able to detect any significant deterioration in fuel economy. The type of roads and the style of driving makes a much bigger impact. I usually get about 65 mpg (diesel) on a long run and 63 mpg on normal rural/town routes - the roof bars/bike makes no difference.

 

[Night Train]

Our car normally gets about 48mpg, with bike on top its more like 43mpg. It does truly amaze me the bike is using up about 10% of the fuel.

What a very strange concept, someone in a 4x4 considering fuel consumption, surely the whole ethos of 4x4 ownership is "I don't give a sh*t about anything other than myself"

Says the person who only gets 48mpg!
I bet farmers care a lot about fuel consumption, as may the energency services.




I get 60-80mpg from my big estate car, with or without bike inside. I will try not to carry it outside if I can help it.

I did a long term test with my car over 6 years measuring everything and found that a pair of roof bars left on increased fuel consumption by about 5%. The aircon made no difference as it is climate control and the whole system runs regardless of settings. Opening a window increased consumption by 10% so it was better to use the aircon then the open window.
Low tyre pressures added up to 7% in fuel consumption whereas excess weight and variable speed made less difference then overall driving style.

 

[I like Skol]

whereas excess weight and variable speed made less difference then overall driving style.

I did this over hundreds of thousands of miles with Merc vans, maintaining meticulous fuel consumption records on a spread sheet and did indeed prove that aircon, payload and variable speeds made negligable difference in comparison to driving style and top speeds. Even hard acceleration didn't have a big effect on fuel consumption as you simply reach your desired speed quicker then ease off at which point the fuel is only trickled in to maintain motion. The biggest savings in fuel use come from sticking to a sensible top speed and watching road conditions to avoid having to slow down unnecessarily. Also, turn off your engine when stationary for any length of time. It infuriates me the number of times I see people sat in their cars with the engine running while waiting outside a school to collect kids or eating their lunch in a supermarket car park. This is just WRONG!!!

Getting back to the OP's Q. You have to accept that carrying something on the outside of the car will have some effect on the fuel consumption, this is unavoidable. Use the rack, roof or rear mounted, when you need to but keep to sensible speeds and remove it if you aren't going to need it for a while.

I have the full 4 bike Thule roof kit for my car and it probably gets fitted once a month for a few days then comes off again to be stored until the next time so extra fuel use is minimised.

 

[Cubist]

It was a serious question, can someone with a Land Rover really have any interest in Fuel economy?

I was sought of thinking on the lines of; if a bike on the roof can make a dramatic effect on economy then then without bike the vehicle must have excellent aerodynamics. If it makes only a small difference then the aerodynamics can not be that good.

Surely the adverse change in aerodynamics of a bike fitted to the outside of a Land Rover would be similar to the weight penalty of a passenger in an articulated lorry.

You touched a nerve mate, that's all.

Yes of course I care about fuel economy. That's why I cycle to work. There are many reasons why I choose to own a Discovery, but despite all the frothy-mouth spleen we see being vented on this forum about what sort of person I must be because I own one, and what sort of driver owning a landrover must make me, I will not simply roll over and let people make huge prejudicial assumptions about what sort of person I am.

After all, if I came onto the forum and assumed you were 74 years old because you drove a Prius, or a sixty-something pipe and slippers man because you drove an S Type Jag, or a Muslim because you drive a Toyota Carina, then I would, quite rightly, get flamed for it.

 

[Globalti]

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?

It's not the first time I've heard this. Since the area of low pressure behind the car is the biggest cost to fuel consumption I guess it's just possible that if you break it up with lots of little sources of turbulence, it might even reduce the effect.

 

[fossyant]

4 up on my roof hammers economy.

Get up to 37/40 mpg on a 70 mile run (keeping to 65-70 and less than 3000 rpm) - with the bikes, and I drop speed to 60 say, then I can get 32-35. If it's windy, then I get an extra hammering. At non-motorway speeds it's not much difference

Largish family saloon with a petrol engine.

 

[Davidc]

I carry my bike(s) inside the car (a decent sized hatchback). When I replace it - planned for 9 years time, I buy 'em new and run 'em for 15 years or 250,000 miles - I may buy a van, much more practical and cheaper, and just hire for the 3 or 4 days a year when I want more seats.

When I had the family living with me I had a 6' x 4' trailer and made a cover which was held on very securely and had 4 bike mounts on it. With the drop in speed for trailer speed limits my fuel consumption with trailer was the same as without the trailer, with or without the bikes. I never understood that, I'd have still expected it to be higher, and higher still with the bikes on it. One big benefit was that I was able to run a smaller and more economical car than I would have if I hadn't had the trailer available for the no more than 10% of journeys when it was used.

 

[corshamjim]

I've seen pictures of someone (Tom Crispin from urc if I recall) who has a trailer which attaches to his bike for carting other bikes around. Obviously not a practical solution for longer journeys though!

 

[byegad]

We drove to Bordeaux from NE England with two bikes on a towbar mount behind my wife's Yaris. Travelling fast we got 48mpg. On long, but not that long runs, at the same speed with out the mount and no bikes we get 48mpg. As far as I can tell there is no penalty for a towbar rack behind the Yaris.

 

[Davidc]

I've seen pictures of someone (Tom Crispin from urc if I recall) who has a trailer which attaches to his bike for carting other bikes around. Obviously not a practical solution for longer journeys though!

Sorry Jim, from experience I can say you're totally wrong, if referring to trailers behind cars rather than bikes. It's the most practical way there is of carrying bikes, especially on longer journeys.

You have to go 10 mph slower to meet the speed limits, but with bikes on the roof or a rear carrier that's likely to be the sensible option anyway. The fairly small trailer has negligible effect on handling, you have to make an effort to remember it's there, and attaching and detaching are much quicker than putting bikes on carriers (about 20 seconds plus checking that the lights are working).

Security - I had a pair of iron bars and very substantial locks passed on to me by its previous owner. They clamped the wheels to the frame, and I had 4 similar devices made for me to lock the bikes from BB to trailer frame.

The furthest we ever went with the trailer plus 4 bikes on it was Suffolk to Valencia return, for which it was not only practical but optimal as a solution. The trailer was also full of camping kit for that one. When using the trailer just for bikes we did use some old concrete building blocks as ballast as the bikes were a bit light on their own.

Including the towball fitting it wouldn't be much more expensive than roof bars for my present car, which can't take a normal tailgate carrier.

The drawback of a trailer is storing it - that's why I had to sell mine when I moved somewhere where it would have been a problem. I've missed it ever since.