Fuel Economy With Bike Rack

[ChristiaanSt]

I am doing a longer trip in December with family and taking my MTB with. Bike gets transported on a Thule towbar rack. 

Question: Will it make a difference if I make a plan to mount the bike without its wheels on to the rack so that it is lower and narrower and sits more "behind" the car instead of sticking out like a wind sail? I have checked and seen that my economy goes from about 5L/100km (without bike) to about 5.8/6L/100km (with bike).

I have an idea of how to do the actual mounting but don't want to go in to that too much now as I think that will steer the convo in a different direction.

opinions?

[leon_pro]

Hey, 

Transporting bikes will always have an effect on the fuel economy. I have roof mounted rack, and it  decreases the economy with the rack only by 1.0l per 100km so it goes to 8.0/100km. with Bikes on it changes 2.0l/100 if not more, if there is a head wind. 

Remember the price of taking the bikes with, are rewarded in the enjoyment of having your bike with you on holiday! 

Is the juice worth the squeeze?  hehe

[W@nted]

  On 11/4/2022 at 5:55 AM, ChristiaanSt said:

I am doing a longer trip in December with family and taking my MTB with. Bike gets transported on a Thule towbar rack. 

Question: Will it make a difference if I make a plan to mount the bike without its wheels on to the rack so that it is lower and narrower and sits more "behind" the car instead of sticking out like a wind sail? I have checked and seen that my economy goes from about 5L/100km (without bike) to about 5.8/6L/100km (with bike).

I have an idea of how to do the actual mounting but don't want to go in to that too much now as I think that will steer the convo in a different direction.

opinions?

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Hi. If possible and using a hanging rack, I have found removing the wheels does help a bit improving the fuel consumption. I experienced this, especially with a sedan car. If transporting a MTB, just remember to not squeeze the brake lever when the wheels have been removed...Or fit some bleeding blocks in the calipers.

However, as mentioned the fuel consumption will increase with the bike loaded, so just make peace with it. 

[Ispeed_V]

INMHO, for a 0.8% saving, i would'nt stress to much.

That said, I normally remove just the front wheel's from my MTB bikes so as to avoid any possibility of exhaust burn.

[The Ouzo]

Done the trials and errors with a sedan.

 

Remove both wheels (but as mentioned put brake blocks in).

Lower the saddle.

Anything that protrudes past the edges of the vehicle causes drag, you want to reduce these protrusions as much as possible.

[guidodg]

also drive slower...makes a HUGE difference with bikes on the roof..

[Milosh]

In my opinion , the risk of loosing or leaving behind a wheel or ThruAxle is not worth the saving.

DIsc's are safe on bike , packing them can dirty them or bend them.

 

  

[Fisan]

  On 11/4/2022 at 6:35 AM, FondTF2 said:

INMHO, for a 0.8% saving, i would'nt stress to much.

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Closer to 10% to 20%

[The Ouzo]

  On 11/4/2022 at 8:31 AM, Milosh said:

In my opinion , the risk of loosing or leaving behind a wheel or ThruAxle is not worth the saving.

DIsc's are safe on bike , packing them can dirty them or bend them.

 

  

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depends on the length of the trip.

Going down to CPT from JHB, very much worth it.

 

Also depends on the vehicle

[M L]

  On 11/4/2022 at 6:04 AM, leon_pro said:

Hey, 

Transporting bikes will always have an effect on the fuel economy. I have roof mounted rack, and it  decreases the economy with the rack only by 1.0l per 100km so it goes to 8.0/100km. with Bikes on it changes 2.0l/100 if not more, if there is a head wind. 

Remember the price of taking the bikes with, are rewarded in the enjoyment of having your bike with you on holiday! 

Is the juice worth the squeeze?  hehe

Expand  

Yeah - R20 per 100km is nothing in biking expense terms.

Edited November 4, 2022 by M L

[Brawler]

  On 11/4/2022 at 8:37 AM, Fisan said:

Closer to 10% to 20%

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If this is true it must be hugely dependent on other factors. 

I do 1400KM a couple of times a year, sometimes with bikes, sometimes not. I struggle to notice a difference in fuel consumption and I watch it like a hawk. This is with two bikes (including a huge 160mm enduro bike) on a hanging rack.

I will say my stress levels go up with a hanging bike rack! I end up looking at the rack in my rear view mirror every few minutes. 

[The Ouzo]

  On 11/4/2022 at 9:13 AM, Brawler said:

If this is true it must be hugely dependent on other factors. 

I do 1400KM a couple of times a year, sometimes with bikes, sometimes not. I struggle to notice a difference in fuel consumption and I watch it like a hawk. This is with two bikes (including a huge 160mm enduro bike) on a hanging rack.

I will say my stress levels go up with a hanging bike rack! I end up looking at the rack in my rear view mirror every few minutes. 

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what vehicle ?

[Fisan]

  On 11/4/2022 at 9:13 AM, Brawler said:

If this is true it must be hugely dependent on other factors. 

I do 1400KM a couple of times a year, sometimes with bikes, sometimes not. I struggle to notice a difference in fuel consumption and I watch it like a hawk. This is with two bikes (including a huge 160mm enduro bike) on a hanging rack.

I will say my stress levels go up with a hanging bike rack! I end up looking at the rack in my rear view mirror every few minutes. 

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You want stress? Try driving a roof rack on a hatchback during a howling Cape Town southeasterly. 😅

[droo]

  On 11/4/2022 at 9:13 AM, Brawler said:

If this is true it must be hugely dependent on other factors. 

I do 1400KM a couple of times a year, sometimes with bikes, sometimes not. I struggle to notice a difference in fuel consumption and I watch it like a hawk. This is with two bikes (including a huge 160mm enduro bike) on a hanging rack.

I will say my stress levels go up with a hanging bike rack! I end up looking at the rack in my rear view mirror every few minutes. 

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Depends on the car. My 1.6 Golf drank petrol with a bike rack on, my 2.5 Forester couldn't give a rodent's rectum. Smaller highly stressed engines are more sensitive to extra load, bigger under-stressed ones generally don't care.

@Chris - if it sticks out beyond the edges it'll make a bigger difference. You'll probably spend that difference on whatever weird rack you're designing though. In time and welding rods. Not that that will stop you...

[OVERDRIVE]

What car are we taking here? (Apologies if this has been asked and answered) 

[ChrisF]

  On 11/4/2022 at 6:50 AM, guidodg said:

also drive slower...makes a HUGE difference with bikes on the roof..

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With the RAV we slowed down about 5km/h to get the same fuel economy - with bikes on the roof.

 

 

 

With the Jetta, and the bikes on the platform rack ..... damn, that thing got thirsty when transporting bikes !!!!