Mythbusters: Is a bike greener than a car?

[darcane]

Was watching the boob tube and caught a commercial for a new episode of Mythbusters with something interesting... It looked like some sort of streamlined motorcycle.

Looked it up, it's an episode called Bikes and Bazookas:
Preview: Mythbusters-bikes-and-bullets
There's some footage of their streamlined bike on that link.

The premise seems to be testing whether cars or bikes produce lower emissions (I presume this is a question because bikes have better mpg but less pollution controls). Looks like they put it to an "ultimate" test by streamlining a bike.

However, to me it seems they add a TON of frontal area in the process. I've never seen a bike on the salt flats that looked like their creation...

Of course, no results at this point. Ya gotta wait for the episode to air later this month.

[Sven7]

Cool. Too bad he had the window open, greatly increasing drag and putting more stress on the engine.

The bike also does look pretty big. Why not just put a rear fairing on?

[PaleMelanesian]

Right. It didn't need to be anything close to that wide. Drag = cdA and they greatly increased the A.

[Big Dave]

If you're willing to ride in a hunkered down crotch rocket position, why not use clips-ons and get narrower?

[Frank Lee]

Regardless of Mythbusters, even if a particular bike model and car model got identical fe, the bike used about 1/5 the materials to make, especially oil-based plastics. There's a lot of emissions in manufacture and disposal too.

[Grant-53]

Sure, the thing lacks refinement. The mirrors are enclosed increasing the width, the all clear panels make it a hot house in the summer, and the rear hatch is awkward. Still it will likely improve mpg by 30% or more. The best part is that the concept of a full faired motorcycle will get a much wider audience. An all weather 250cc motorcycle that gets 150 mpg for around $5000 USD may prove very attractive to commuters.

[Sven7]

Originally Posted by Grant-53

Sure, the thing lacks refinement. The mirrors are enclosed increasing the width, the all clear panels make it a hot house in the summer, and the rear hatch is awkward. Still it will likely improve mpg by 30% or more. The best part is that the concept of a full faired motorcycle will get a much wider audience. An all weather 250cc motorcycle that gets 150 mpg for around $5000 USD may prove very attractive to commuters.

BMW sort of tried that with the C1. Of course, including the young woman wouldn't have hurt sales.

[sendler]

I would be intersted to see them revisit the car vs bike myth using the Honda CBR250R. The best bike they had came back with 56 mpgUS so they put a giant streamliner fairing on it and got it up to 71. The CBR averages 71 on fuelly right off the showroom floor and has an O2 sensor and a big exhaust (big catalyst?) so it might be cleaner than their best test bike. I get 87 mpgUS all summer long on my 64mph commute. They put the emphasis on CO, HC, and NOx, disregarding the fact that the bikes used less gas and put out less CO2. In the end, they just told everybody to stick with their car. I hope one day they will try it again with the $4000 Honda.

[roflwaffle]

Originally Posted by Frank Lee

Regardless of Mythbusters, even if a particular bike model and car model got identical fe, the bike used about 1/5 the materials to make, especially oil-based plastics. There's a lot of emissions in manufacture and disposal too.

There are, but sooner or later they're trumped by rubber use. A bike usually goes through something like three to six times more rubber than a car. IIRC it's something like an extra ~150-300 lbs per 100k miles, which is equivalent to the same weight in plastic or about three times that weight in steel.

For a bike that goes through tires in a reasonable amount of time, say ~15k-20k per set, the comparison isn't too bad because it only reaches the embodied energy of the car after a few hundred thousand miles, but a sport bike that goes through those tires in half the time or less will add the energy equivalent of a half ton of steel every ~100k or so.

[sendler]

The major consideration should be fuel consumption which can be much less with a motorcycle. Especially for around town errands where there will be no comparison between car and bike. The entire continents of India and South East Asia get by entirely with small two wheelers that get 130mpgUS. My 250 is considered a luxury model there. I commute on the highway so need the better bike but still get 87.