norsecarnut

Driving a large Pathfinder isn't going to be affected as much by a bike on the roof.

yeewiz

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.

norsecarnut

Yeah, to me, there are rarely going to be reasons strong enough to ship vs bring it with me if I'm already driving.

Kell

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.

Kell

We're talking about a round trip distance of around 1200 miles. Just googled a company that will courier a bike anywhere in the UK for £21.50. So, £43 return.

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.