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Old 01-04-2013, 05:54 PM   #47
ph0rk
Doesn't Care
 
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Joined: Dec 2009
Location: Oaktown
Oddometer: 2,048
Quote:
Originally Posted by icebox View Post
cx, hate to tell you but a motorcycle has the drag of the average barn door, an Accord is pretty aero, and a Strom, had one, with a passenger, and luggage is about as aerodynamic as a barn going sideways. Add elevation power loss of 3% / 1000' and at 7,000' your loaded 48 HP Wee gets pretty weak headed West into a 40 MPH head wind.
Besides, in the Accord you can roll up the windows so the buffeting doesn't make you deaf. Sometimes there is no substitute for cubic inches, or centimeters.

Now as to the OP, I get the winter "buy another bike itch" every year, and winter has a lot to do with it. My winters are worse than yours, as soon as I can get back on, the itch seems to fade. Right now, 6 F, and going down to minus something I might need to buy two.
I'n not sure who cx is.

Ah yes, 40 mph headwinds at 7000 feet. Sure, that happens every day (outside of the Rockies and Sierras, not much at all in the US). My bike had plenty of power (sans headwind) around 5000-6000 feet on a steep grade, two up. Around here, elevations anywhere close to that and no wind would be only a headwind for long, and then you've got other problems, problems cars aren't immune to either (40mph side wind sucks no matter what vehicle you're in). Sustained winds that speed are rare here, are they an everyday thing where you live?

The same story is true with a Honda fit as with an accord, with even worse power numbers. You don't need more than 65 hp to tour at legal speeds unless you're ridiculously over the GVWR of the bike.


An engine is a pump, so power loss at altitude (temperature held constant) is just due to air density. Assuming the same air temp, you've got 781.858 milibars at 7k, and 1013.25 at sea level (of course, more like 984-998 where I live):

781.858/1013.25 = 77.163% of sea level air density, and thus 77.163% as much air can flow through the engine.

65hp * 77.163 = 50.156 (again, same air temperatures assumed),

I suppose if you lived at that elevation you might get bent out of shape about it, but the majority of the US land area is at far lower elevations.



Nothing wrong with wanting more power than that, but need it? no. I suppose if you want to sit at 95mph actual at 7,000 feet into a 40 mph headwind you need a busa, but otherwise...
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