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Pittsburgh hills



 
 
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  #1  
Old November 26th 12, 12:23 AM posted to rec.bicycles.tech
[email protected]
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Posts: 2,673
Default Pittsburgh hills

Article about a race in Pittsburgh's hills. 37% grade, anyone?

http://www.post-gazette.com/stories/...-dozen-663572/

or

http://tinyurl.com/booeuyl

For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!

- Frank Krygowski

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  #2  
Old November 26th 12, 12:48 AM posted to rec.bicycles.tech
AMuzi
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Posts: 13,447
Default Pittsburgh hills

On 11/25/2012 6:23 PM, wrote:
Article about a race in Pittsburgh's hills. 37% grade, anyone?

http://www.post-gazette.com/stories/...-dozen-663572/

or

http://tinyurl.com/booeuyl

For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!

- Frank Krygowski


antigravity force field . Or EPO maybe?

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #3  
Old November 26th 12, 01:28 AM posted to rec.bicycles.tech
James[_8_]
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Posts: 6,153
Default Pittsburgh hills

On 26/11/2012 11:23 AM, wrote:
Article about a race in Pittsburgh's hills. 37% grade, anyone?

http://www.post-gazette.com/stories/...-dozen-663572/

or

http://tinyurl.com/booeuyl

For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!

- Frank Krygowski


Assumptions:

300 W continuous.

60 rpm minimum, 1 rev per second.

175mm cranks.

Percentage gradient is measured as;
gradient = (elevation x 100) / (distance travelled)

Ignoring wind resistance.

Mass of bike + rider = 90 kg.

700c wheels.

Then:

Vertical speed is given by;

P = m*g*dh/dt

300 / (90 * 9.81) = 0.34 m/s

Road speed is then;

0.34 * 100 / 37 = 0.92 m/s, or 3.31 km/h

Gearing required would be;

0.92 = wheel circumference * chainring / sprocket

0.92 approx = 2.014 * 18 / 38

I may need more Watts or a smaller back wheel.

--
JS
  #4  
Old November 26th 12, 02:00 AM posted to rec.bicycles.tech
Jay Beattie
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Posts: 4,322
Default Pittsburgh hills

On Nov 25, 4:48*pm, AMuzi wrote:
On 11/25/2012 6:23 PM, wrote:

Article about a race in Pittsburgh's hills. *37% grade, anyone?


http://www.post-gazette.com/stories/...-city/with-gri...


or


http://tinyurl.com/booeuyl


For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!


- Frank Krygowski


antigravity force field . Or EPO maybe?


Personally, I would run the 100 yards and save the time and money
necessary to re-gear my road bike. I know that is not part of the
mystique of the ride, but really, it is probably more efficient to
walk or run up 37%, particularly on cobbles in the snow.

Assuming I had to stay on a bike -- I could swap enough parts around
to come up with a triple with a 30/28. That should do it. Maybe use
my cross bike because the long chain stays keep the rear end planted
-- although it is not the lightest bike in the stable. The hard call
would be picking tires -- not too heavy, good grip and float on the
cobbles, but not too slow on the rest of the course -- this is where
some fatty sew-ups would be great.

-- Jay Beattie.
  #5  
Old November 26th 12, 07:25 AM posted to rec.bicycles.tech
yirgster
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Posts: 130
Default Pittsburgh hills

http://www.post-gazette.com/stories/...-dozen-663572/


Very interesting. I lived 5 years in Pittsburgh. I only knew one person who even had a bike. A Schwinn Varsity. I remember the Varsity being highly ranked by Consumer Reports. Not that this dates me or anything.

But, from the article: "(By way of comparison, most hills in San Francisco are in the 20 percent grade.)"

This doesn't strike me as accurate(though it may be). It's been a zillion years since I've ridden my bike up hills in SF but I wouldn't have thought them as a whole as being 20+%.

Guess I could look some up on strava, but I'm hoping someone just sort of knows.
  #6  
Old November 26th 12, 10:52 AM posted to rec.bicycles.tech
Graham
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Posts: 206
Default Pittsburgh hills


wrote in message ...
Article about a race in Pittsburgh's hills. 37% grade, anyone?

http://www.post-gazette.com/stories/...-dozen-663572/

or

http://tinyurl.com/booeuyl

For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!

- Frank Krygowski


Well according to the organisor: "I recommend a low gear of 39x27 for racers, and 34x28 or lower for recreational riders".

That would certainly be over optimistic for me. The lowest I can go is 34x32 and that's fine for the 20-25% grades that are relatively common where I ride but 37% would be a very serious challenge even though it is only 100yards. Traction would certainly be a problem particularly climbing out of the saddle on cobbles. Having studied the photo gallery from the race most people seem to be on standard 23mm slicks. The only guy shown completely on the deck has treaded tyres.

Technique also looks critical. Going straight up on the cobbles looks like the only way. Any temptation to slalom to reduce the gradient looks doomed to failure given the photos.

It also looks like a CF steed with relatively high end, light weight wheels is the weapon of choice for the majority. It would also appear that everyone is dressed in cycling "sports" clothing - there is even a pink sleeved jersey and shorts!!! No every day clothes in sight. Also everyone in the 10 photos shown is wearing a helmet. So here we do have an example of where the terrain you ride in can influence your choices and that risk levels can be significantly higher than flat land cruising. That said I do not think I would go as far as the organisors who require you to sign to say: "I am aware that participation in the Ride is hazardous and that I could be seriously injured or even killed" I think things are exagerated a bit in the US

Graham.
  #7  
Old November 26th 12, 12:18 PM posted to rec.bicycles.tech
Graham
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Posts: 206
Default Pittsburgh hills


"James" wrote in message ...
On 26/11/2012 11:23 AM, wrote:
Article about a race in Pittsburgh's hills. 37% grade, anyone?

http://www.post-gazette.com/stories/...-dozen-663572/

or

http://tinyurl.com/booeuyl

For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!

- Frank Krygowski


Assumptions:

300 W continuous.

60 rpm minimum, 1 rev per second.

175mm cranks.

Percentage gradient is measured as;
gradient = (elevation x 100) / (distance travelled)

Ignoring wind resistance.

Mass of bike + rider = 90 kg.

700c wheels.

Then:

Vertical speed is given by;

P = m*g*dh/dt

300 / (90 * 9.81) = 0.34 m/s

Road speed is then;

0.34 * 100 / 37 = 0.92 m/s, or 3.31 km/h

Gearing required would be;

0.92 = wheel circumference * chainring / sprocket

0.92 approx = 2.014 * 18 / 38

I may need more Watts or a smaller back wheel.


I suspect you have a lot more watts when you consider that whilst 37% this is only 100 yards. In your example above that's roughly 1 minute 40 seconds. My bet is that you could knock out at least 500 watts for the 1 minute it would take you at that power level. It then becomes an optimisation between time, strength, traction and cadence. Not being a hill climb racer I do not have a feel for how that comes out.

Graham.
  #8  
Old November 26th 12, 12:41 PM posted to rec.bicycles.tech
Wes Groleau
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Posts: 555
Default Pittsburgh hills

On 11-26-2012 05:52, Graham wrote:
That said I do not think I would go as far as the organisors who require you to sign to say: "I am aware that participation in the Ride is hazardous and that I could be seriously injured or even killed" I think things are exagerated a bit in the US


What is exaggerated is the tendency to sue for any excuse you can cobble up.

--
Wes Groleau

“There ain't nothin' in this world that's worth being a snot over.”
— Larry Wall

  #9  
Old November 26th 12, 02:32 PM posted to rec.bicycles.tech
Nate Nagel[_2_]
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Posts: 1,872
Default Pittsburgh hills

On 11/25/2012 07:23 PM, wrote:
Article about a race in Pittsburgh's hills. 37% grade, anyone?

http://www.post-gazette.com/stories/...-dozen-663572/

or

http://tinyurl.com/booeuyl

For tech, I suppose we could discuss what equipment you'd use for a 37% grade. On cobblestones!

- Frank Krygowski


Oh man now I am nostalgic. Not as steep as the hill in the article but
still quite challenging even on foot is Negley between Fifth and
Wilkins... I used to live near the top of that hill ages and ages ago,
and there's always some idiot that thinks he can get down it in the snow
rather than taking an extra 3 minutes and taking the long way :/ Yes
there is a traffic light at the bottom (intersection with Fifth, one of
the main streets through Oakland)

I bet if I still lived there I'd be in better shape than I am now :/

To answer your question, I'm running a 26/36/48 (I think; I'm actually 5
hours away from my bike at the moment - closer to Pittsburgh than home)
front with a 12-26 SRAM 9-speed rear, Campy FD and Ultegra rear with
Dura-Ace downtube shifters. Wheels are CR-18s with 32mm Paselas. So
that actually should work OK, maybe fully loaded I would wish for a
different cassette but other than that I think that that setup would
work. Other bike has same cassette but "compact double" front and if I
wanted to play in the snow I could change to 28mm cross tires - that one
has Velocity Deep-Vs and all shimano brifters and derailleurs.

I actually started riding as a kid with my parents on rural roads
outside Pgh. so I guess you can see what kind of roads influenced my
mindset as to how a "practical" bike should be equipped.

nate

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replace "roosters" with "cox" to reply.
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  #10  
Old November 26th 12, 02:39 PM posted to rec.bicycles.tech
Nate Nagel[_2_]
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Posts: 1,872
Default Pittsburgh hills

On 11/26/2012 02:25 AM, yirgster wrote:
http://www.post-gazette.com/stories/...-dozen-663572/


Very interesting. I lived 5 years in Pittsburgh. I only knew one person who even had a bike. A Schwinn Varsity. I remember the Varsity being highly ranked by Consumer Reports. Not that this dates me or anything.

But, from the article: "(By way of comparison, most hills in San Francisco are in the 20 percent grade.)"

This doesn't strike me as accurate(though it may be). It's been a zillion years since I've ridden my bike up hills in SF but I wouldn't have thought them as a whole as being 20+%.

Guess I could look some up on strava, but I'm hoping someone just sort of knows.


http://en.wikipedia.org/wiki/Russian..._San_Francisco

Wiki (always a reliable source, but still) says Lombard Street (the
famous street from the 60's Corvette commercials and also the movie
Bullitt) would have been a 27% grade without the switchbacks. I've
never been to SF though so I can't say how the hills there compare to
Pittsburgh.

nate


--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
 




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