Rear cycle carriers
#12
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Joined: Jun 2008
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From: Las Vegas, USA
My Ride: 2007 530xiT: CPO purchase in 2008, used by a BMW exec previously, and like-new when I got it. Compared to my other cars, at first I thought it felt heavy and steering was too heavy. Now, I really enjoy driving it in town and on the freeway. On my
1800 miles / 27 mpg = 66.67 gals x $3.50 per gallon = $233 in gas cost
10% drag penalty: 1800 miles / 27 mpg * .9 = 74.07 gals x $3.50 = $259
20% drag penalty: 1800 miles / 27 mpg * .8 = 83.33 gals x $3.50 = $291
30% drag penalty: 1800 miles / 27 mpg * .7 = 95.24 gals x $3.50 = $333
40% drag penalty: 1800 miles / 27 mpg * .6 = 111.11 gals x $3.50 = $389
Soooooo, a 30% drag penalty means $100 extra in gas. I don't know. 30% drag because of a skinny bike on your roof sounds iffy but kind of plausible? I have a difficult time believing a 40% penalty though.
#14
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Joined: Oct 2007
Posts: 290
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From: High Wycombe, Bucks, England
My Ride: 2005 530d M Sport Touring : Carbon Black : Half Leather : Pro DVD Sav Nav : TV : Active Cruise : Front/Rear Parking : Bluetooth Phone : 6 CD : Dark Poplar Wood : Folding Mirrors : 5 year Servicing Pack
I'm not saying (and nor was the original information) that it would actually be worth doing. Only that as a comparison, it was surprising just how much extra fuel carrying a bike on the roof uses.
Never really thought about the roofbox option, we have got a 560 litre box so it might work.
I did (on a couple of occasons) take the wheels off my old bike and get it in the back of my old TT.
Never really thought about the roofbox option, we have got a 560 litre box so it might work.
I did (on a couple of occasons) take the wheels off my old bike and get it in the back of my old TT.
#15
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Joined: Oct 2007
Posts: 290
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From: High Wycombe, Bucks, England
My Ride: 2005 530d M Sport Touring : Carbon Black : Half Leather : Pro DVD Sav Nav : TV : Active Cruise : Front/Rear Parking : Bluetooth Phone : 6 CD : Dark Poplar Wood : Folding Mirrors : 5 year Servicing Pack
That doesn't sound right, so let's do the math. I don't know the distance in the Scotland example so I'll use an American example: San Francisco, CA to Dallas, TX is 1800 miles. My 530xiT wagon without roof racks gets 27 mpg on this trip. Therefore:
1800 miles / 27 mpg = 66.67 gals x $3.50 per gallon = $233 in gas cost
10% drag penalty: 1800 miles / 27 mpg * .9 = 74.07 gals x $3.50 = $259
20% drag penalty: 1800 miles / 27 mpg * .8 = 83.33 gals x $3.50 = $291
30% drag penalty: 1800 miles / 27 mpg * .7 = 95.24 gals x $3.50 = $333
40% drag penalty: 1800 miles / 27 mpg * .6 = 111.11 gals x $3.50 = $389
Soooooo, a 30% drag penalty means $100 extra in gas. I don't know. 30% drag because of a skinny bike on your roof sounds iffy but kind of plausible? I have a difficult time believing a 40% penalty though.
1800 miles / 27 mpg = 66.67 gals x $3.50 per gallon = $233 in gas cost
10% drag penalty: 1800 miles / 27 mpg * .9 = 74.07 gals x $3.50 = $259
20% drag penalty: 1800 miles / 27 mpg * .8 = 83.33 gals x $3.50 = $291
30% drag penalty: 1800 miles / 27 mpg * .7 = 95.24 gals x $3.50 = $333
40% drag penalty: 1800 miles / 27 mpg * .6 = 111.11 gals x $3.50 = $389
Soooooo, a 30% drag penalty means $100 extra in gas. I don't know. 30% drag because of a skinny bike on your roof sounds iffy but kind of plausible? I have a difficult time believing a 40% penalty though.
https://www.paisleyfreight.com/?sour...FUEY4QodhFO81Q
Our diesel is £1.36 a litre so that's £5.14 a gallon (or $8.20 USD a gallon). I would normally get around 30mpg on this trip, so following your example above.
1200 / 30 = 40 gallons at £5.14 per gallon = £205
10% drag penalty: 1200 miles / 30mpg * .9 = 44.4444 gals x £5.14 = £228 (+£23)
20% drag penalty: 1200 miles / 30mpg * .8 = 50 gals x £5.14 = £257 (+£52)
30% drag penalty: 1200 miles / 30mpg * .7 = 57 gals x £5.14 = £293 (+£88)
40% drag penalty: 1200 miles / 30mpg * .6 = 66.666 gals x £5.14 = £342 (+£137)
Even with my roofbox on, I've seen the MPG go down to 27MPG or so (10%). A bit of quick online googling says that even a rear carrier can affect MPG by up to 20%. I can believe roof-mounted systems could cause up to 30%, and yet just a 10% decrease in MPG would be enough to pay for the bike to be couriered one way.
But like I said above, it was never meant to be a genuine alternative, only for illustrative purposes.
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