How steep is the Manayunk Wall? It’s not a real wall, of course, but a torturous half mile climb from Main to Pechin Street during the Wachovia USPRO Cycling Championship. All the references I’ve seen refer to the Wall as having a 17% grade. The grade of a hill is defined as the vertical climb (change in altitude in feet above sea level) divided by the horizontal distance traveled.

One bicyclist estimates the impact of various grades as follows:

• 0% grade is exactly flat (and a negative grade, less then zero, is downhill).
• 2% grade does not seem very steep, but it's enough to substantially reduce forward speed, and for most riders it will absorb more than half their power output.
• 6% grade is enough to cut speed to well under half, and absorb more than 80% of a rider's power output (leaving less than 20% to fight air resistance and rolling friction).
• 10% grade, and anyone who is not a fit and frequent rider is off their bike walking -- and anyone who is not a racer is reaching for all the extra power they've got.

But when you compute the distances and altitude changes on Google Earth, the overall grade of the Manayunk Wall is less than 10%. There are intervals when the grade is 17%. In one 150 yard stretch, there is even an 18.5% grade (I had to compute the intervals from street to street because of presbyopia).



For the overall grade to be 17%, the elevation from sea level would have to change from 39 feet at Main Street to 488 feet — instead of 279 feet — at Pechin. Since the highest spot in Philadelphia is 432 feet (E. Evergreen Avenue in Chestnut Hill), an overall grade of 17% over a half mile rise appears to be impossible.

Maybe my arithmetic is wrong (it wasn’t my best subject). Maybe the Wall is defined differently. Anyway, it doesn’t diminish, in the least, the preternatural endurance of these athletes. For you East Fallsers, it would be like cycling up two Gypsy Lanes. These days, I would need a Sherpa to get to the top of the Wall.

The only reason I noticed this discrepancy was that I was estimating the steepness of various streets in Manayunk and East Falls. Most people prefer a diagonal vista over a horizontal flat view, and I believe this preference is reflected in real estate prices. My question is how steep is too steep before the value of a home is diminished? Above a certain grade, the vestibular system rebels, ice and snow make driving treacherous, and the European hillside charm vanishes.

My guess is that the detriments start outweighing the benefits above a 12% - 14% grade. But check out Google Earth to compute the grade of your favorite streets, and make your own determination.

http://www.onlineconversion.com/foru...1086616424.htm

Slope is rise/run x 100 (to get a percent)

Note that a 100% grade is a 45 degree slope (not a 90 degreee slope)

For most kinds of "sporting events" where there is a "natural course" - the common rule of thumb is to set the margin at the "toughest" section that can be reasonably construed to be a realsitic representation. of a section of the course...

Its not unual to cite the 17% slope even if the entire "hill" is not 17% - but that there are resonable long sections that qualify at 17%.

Take a look at the Tour De France slopes.
Certian slopes are not "that bad" when looking at the pure numbers, but the fans (and the riders) have elevated certian climbs to mythical status (Ventoux , Alpe d'Huez, etc)

Pssst...that's the Commerce Bank International Championship now. Wachovia bailed.

It looks like the 17% slope comprises about 20-25% of the entire climb. I'll take your word for it; the only thing I know about cycling is how to fall off.

Thanks. When I left town, it was Core States. Did Wachovia buy Core States? I can't keep up with sports sponsorship changes.

I did the Manayunk Wall once...no way could I do it right now, what with my plantar fasciitis foot injury. But maybe again someday!

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History of the Jews of South Philly~~ http://www.nmajh.org/exhibitions/stillhome/

It levels off significantly once you're above Manayunk Ave. Perhaps they just include from Main St. to Manayunk, or more fittingly, Cresson St. to Manayunk - which is the steepest stretch of the hill.

Silverwood to Fleming is the steepest part of the wall.

The last I heard, they were going to simply rename it the Philadelphia International Championship. Did Commerce offically add their corporate branding to it yet?

I have done it (biked the wall) but every three four houses I have
to stop my bike and lie down for a few minutes ......

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