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Old 06-07-2020, 12:49 AM   #1 (permalink)
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Transporting a Bike min Aero drag

Not sure if this has been addressed. For discussion we are talking a normal adult bike, outside a normal sedan, at highway speeds, for a multi thousand mile road trip, and hoping to minimize any added drag. For now, best to ignore road dirt concerns, its not a high cost/value bike, I will be riding it daily, so ease of mount/dismount would be helpful, I'd prefer no bike disassembly, and I'm willing to push the envelope.

Seems like the typical solution is bike standing up crossways behind the trunk on a typical receiver hitch mount. That IMO leaves a lot of bike disrupting air flow exposed.

One idea is, lay/lean it down or even flat. Legally, as long as its with 48" of car's tailights, its no problem. I could make the bike run same direction of car again standing up, which might make for parking hassles, and at least a tail/stop light is added. I could build a transport fairing, but for time/hassle, I'm not inclined to expend any effort beyond a 1/3? fairing, and not sure if it that gives enough bang for buck/effort. I could also maybe make that solution a lay flat alternative. I don't care what it looks like, form follows function and all.

Anybody solved this type of problem, how, and get good results?

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Old 06-07-2020, 03:36 AM   #2 (permalink)
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Brompton.

Normal riding position:



Folded:



Drag penalty: zero.

But they're not cheap, unfortunately.

But many folding bikes are fairly cheap, and if you get a good one, it can transform how you think of bikes.

(Julian: owner of a Brompton, and restoring a Moulton.)
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Old 06-07-2020, 05:04 AM   #3 (permalink)
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Quote:
Seems like the typical solution is bike standing up crossways behind the trunk on a typical receiver hitch mount. That IMO leaves a lot of bike disrupting air flow exposed.

[snip]

Anybody solved this type of problem, how, and get good results?
Yes, but you've disallowed the solution so I won't post the pic from my album. For around town where you're taking the bike on and off it's best.

The thread would work best it you provided some context, like.... the vehicle. Get a Golf GTI and take off the front wheel and throw it all in the back. Get the diesel.
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Old 06-07-2020, 03:03 PM   #4 (permalink)
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Guess I'm breaking new ground, again. I covered all the pertinent personal parameters in my opening comment. I did not however mention, I am not willing to ride a bike that is likely somewhat inadequate on trails and miles long rides, and likely less stable, to solve this issue, and I am not willing to travel with a high dollar bike that is effectively "break in bait" when I'm finished riding and I store it, and decide to take an out of view long hike.

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Old 06-07-2020, 05:22 PM   #5 (permalink)
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Quote:
Guess I'm breaking new ground, again.
Once again define 'a normal adult bike, outside a normal sedan'. What is normal to you?

Is the 'normal sedan' a notchback? Does the 'normal adult bike' have a removable front wheel?

Your not breaking new ground except for posting in Aerodynamics instead of Ecomodding Central or General Efficiency. Central has the most traffic. You want to attract comment from someone like Bicycle Bob or Toecutter.

The picture I wasn't willing to post has a ~$120 bike. The cable lock locks it to the back bumper. The front wheel comes off, but I don't bother. I haven't tested the mileage penalty, but it's within the wake of a 'dirty' car, a [normal] VW Beetle.
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Old 06-07-2020, 06:10 PM   #6 (permalink)
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Quote:
Originally Posted by j-c-c View Post
Guess I'm breaking new ground, again. I covered all the pertinent personal parameters in my opening comment. I did not however mention, I am not willing to ride a bike that is likely somewhat inadequate on trails and miles long rides, and likely less stable, to solve this issue, and I am not willing to travel with a high dollar bike that is effectively "break in bait" when I'm finished riding and I store it, and decide to take an out of view long hike.

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No a folder wouldn't be good on really rough trails (ie trails requiring a mountain bike) but it would certainly be fine for normal trails and long rides. And I don't quite see how it is 'break-in bait' - inside a car it wouldn't be visible.

As for stability / practicality / etc, I am a fan of small wheel bikes and other pedal machines. In fact I wrote a whole book on their advantages (a book that few people are buying!).



Certainly in your position I'd take a good quality folding bike. In fact, the last long driving holiday I went on, I took my Brompton.
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Old 06-08-2020, 12:21 AM   #7 (permalink)
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removing the front wheel is probably the easiest aeromod available.
My beetle and mountain bike combo I took to commute every day for a year, but not at freeway speeds ever.
I could see bike wheel in either mirror. If you took off the front wheel, and used a disc brake block if necessary, you could shift it sideways to get the bike into the wake more properly.
I made my own hitch mount bike rack to get it as close to the back of the beetle as possible. That's the other thing, tucking it in tight to the rear of the car.
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Old 06-08-2020, 07:31 AM   #8 (permalink)
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Quote:
Originally Posted by freebeard View Post
Once again define 'a normal adult bike, outside a normal sedan' I guess the "normal" here was a bridge too far. What is normal to you? Since you asked, a foldup bike is not, and small wheel bikes I gave up when i stopped doing bike tricks when I was 12, and they are very useful for that, regardless I still find advantages in larger wheel bikes for my application, others obviously have different needs.

Is the 'normal sedan' a notchback? Could be, does that matter much from a "aero" standpoint on this context, it only matters to me from the standpoint of on how much aero interaction the bike will generate, no matter what it is, I'm looking for ideas to reduce that drag, within my stated parameters Does the 'normal adult bike' have a removable front wheel? Yes it does, but my original parameter excludes that "normal" solution

Your not breaking new ground except for posting in Aerodynamics instead of Ecomodding Central or General Efficiency. Central has the most traffic. You want to attract comment from someone like Bicycle Bob or Toecutter. I guess then the thinking is they are better sources for Aero drag reduction concepts concerning non normal items attached to the outside of a "normal sedan" temporarily?

The picture I wasn't willing to post has a ~$120 bike. The cable lock locks it to the back bumper. The front wheel comes off, but I don't bother. I haven't tested the mileage penalty, but it's within the wake of a 'dirty' car, a [normal] VW Beetle. I guess then that was stating the obvious, or why we don't attach it to the front bumper? A forum that is so focused to minimize "wake" would seem to be a fertile ground to focus in on locating that wake's "sweet spot" to best transport a bike, but I guess not.
The "theft bait" comment I thought was self explanatory, being the more expensive eye candy an item is ( since taking it out and riding is its main function), the greater attention it gets and the payoff is greater for stealing it.
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Old 06-08-2020, 07:42 AM   #9 (permalink)
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I've owned several folding bikes. I would not own one again.

I like the idea of turning the bike horizontally. My vote is hitch mounted, horizontal, with as much removed as is convenient. E.g. seat, front wheel.
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Old 06-08-2020, 08:10 AM   #10 (permalink)
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Quote:
Originally Posted by Ecky View Post
I've owned several folding bikes. I would not own one again.
Off topic, I know.

But don't get me started on small wheeled bikes. So many cheap ones are crap, and so people assume that they're all crap. In fact small wheeled bikes have major advantages over traditional bikes. (But, if only because of scale economies, price isn't one.)

In terms of folders, Bromptons are a class act. Apart from the fact it's much more nimble than a large wheel bike, a blindfolded rider would be hard put to tell the difference between a Brompton and a traditional bike. And yet it fits in a normal suitcase, with nothing removed from the bike. (I bought mine in London and it flew home to Australia in my luggage at no extra charge.)

But then, if you want me to really get excited, start to talk about recumbent trikes...

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