Quoted message said:On Wed, 26 Jul 2006 23:12:31 +0100, Kinky Cowboy <[email hidden]>
Quoted message said:We have plenty of hills steeper than 16% in England, although they
don't sustain for long. Hill climb courses are often less than 1km
long.
Kinky Cowboy*
Dear Kinky,
Er, judging by the altimetry, English climbs steeper than 16% are
rarely as much as _half_ a kilometer long--that's the unit used for
the grades.
Browse through a few of the climbs at the site and see what they
measured for yourself:
http://ciclismo.sitiasp.it/motore2.aspx?sid=c535c5bb63b240d19dba428a4b232ea0&lista=true&quanti=20&url=in&ID=0&pagina=1&filtra=null&da=az&come=af&lingua=eng&commenti=False
or http://tinyurl.com/gf8dy
The steepest half-km that I noticed was 16.4%, but I'm willing to
learn of paved climbs not on the list (the site would love to hear
about them), and I naturally agree that shorter sections are steeper.
We tend to see a 15%, 20%, 25%, or 30% road sign meant for a hairpin
or a short bend and then apply it quite a ways up the road through
much flatter sections.
(After a short stretch of real 30% grade, you can't blame your legs
for thinking that that the road is still much too steep, even if it
drops back to 12% for four times as long.)
The misunderstanding is harmless, but you'll rarely lose money betting
that people overestimate grade and distance.
Odometers have improved our notions of distance, but grade is still
harder to measure than the seats of our pants realize.
I've measured the grade of that upper curve in my daily S-bend down to
the Arkansas River. It really is about 10%. But it's also noticeably
steeper than most of the rest of the S-bend. For some reason, however,
I prefer to mention that 10% corner. The speedometer keeps me more
hon--er, accurate about top speed, which was 37.5 mph today.
For fun, try filling out the test below. It shows why we have such
trouble judging grade. Skip a few degrees as you go higher. If there's
any interest, I'll post the answers (which I certainly don't
remember).
1% grade = _____ degrees 16% grade = _______ degrees
2% grade = _____ degrees 17% grade = _______ degrees
3% grade = _____ degrees 18% grade = _______ degrees
4% grade = _____ degrees 19% grade = _______ degrees
5% grade = _____ degrees 20% grade = _______ degrees
6% grade = _____ degrees 21% grade = _______ degrees
7% grade = _____ degrees 22% grade = _______ degrees
8% grade = _____ degrees 23% grade = _______ degrees
9% grade = _____ degrees 24% grade = _______ degrees
10% grade = _____ degrees 25% grade = _______ degrees
11% grade = _____ degrees 26% grade = _______ degrees
12% grade = _____ degrees 27% grade = _______ degrees
13% grade = _____ degrees 28% grade = _______ degrees
14% grade = _____ degrees 29% grade = _______ degrees
15% grade = _____ degrees 30% grade = _______ degrees
That covers grades up to the 30% on the sign whose link appeared in an
earlier post. The point of the exercise is to remind us just how hard
it would be to estimate a grade accurately without instruments, which
is why the climbs of Europe site uses altimetry rather than just
repeating what everyone "knows".
Don't misunderstand me--I'm not denigrating UK climbs. I firmly
believe that there are plenty of paved half kilometers in England
steeper than I'm willing to pedal up.
Cheers,
Carl Fogel
An email just asked why I haven't posted the answers for what grade%
means in degrees.
Er, because I saw no posts showing curiosity?
But if grade% = tan(degrees, then . . .
Quoted message said:For fun, try filling out the test below. It shows why we have such
trouble judging grade. Skip a few degrees as you go higher. If there's
any interest, I'll post the answers (which I certainly don't
remember).
1% grade = _0.57 degrees 16% grade = ___9.09 degrees
2% grade = _1.15 degrees 17% grade = ___9.65 degrees
3% grade = _1.72 degrees 18% grade = __10.20 degrees
4% grade = _2.29 degrees 19% grade = __10.76 degrees
5% grade = _2.86 degrees 20% grade = __11.31 degrees
6% grade = _3.43 degrees 21% grade = __11.86 degrees
7% grade = _4.00 degrees 22% grade = __12.41 degrees
8% grade = _4.57 degrees 23% grade = __12.95 degrees
9% grade = _5.14 degrees 24% grade = __13.50 degrees
10% grade = _5.71 degrees 25% grade = __14.04 degrees
11% grade = _6.28 degrees 26% grade = __14.57 degrees
12% grade = _6.84 degrees 27% grade = __15.11 degrees
13% grade = _7.41 degrees 28% grade = __15.64 degrees
14% grade = _7.97 degrees 29% grade = __16.17 degrees
15% grade = _8.53 degrees 30% grade = __16.70 degrees
Basically, add 0.57 degrees for each 1%, slowly decreasing to 0.53 or
so in this range. Very few people can estimate such tiny angles.
Mostly, we gear down and lower our speed until we stop gasping for
breath.
And yes, there are two kinds of grade%, one that uses elevation
divided by map distance (you went 5280 feet from point A to point B on
a map and climbed 528 feet, so grade = 10%) and the other that uses
elevation divided by actual distance (the hypotenuse is longer, so in
real life you had to pedal 5,306 feet, 4 inches, an extra 26.33 feet
per mile, a difference of only 0.5%.
At "30%" grade, however, the disparity between the two methods becomes
more noticeable. Either way, you climb 1584 feet, but one way, you
pedal only 5036.8 feet (steep), the other way you pedal 5512.5 feet
(spreading the work out over 10% more distance).
That there are two ways to calculate grade% is one explanation for the
30% to 35% range of estimates for steep hills like Fargo Street in Los
Angeles.
In real life, of course, paved roads rarely maintain grades as even as
railroad grades for very long--there's no pressing need for such
precision with cars or bicycles.
CF
