Grade percent or angle ?

jautukas87

victorcarrera wrote: »

But does it discard for example a short decent between two ascents when calculating overall trip gradient?

I thinks that you mean average. So they take starting point of elevation and end point of elevation. And then calculate average. Confusing stuff.

stopped_clock

Grand so, that's the definition sorted.

I still don't have a great feel for how steep something is in reality though. I'd like to be able to guess what % something is when cycling up it.

Any guides as to what's "steep", "not so steep", "gentle incline" etc? Obviously it's subjective...

Lumen

stopped_clock wrote: »

Any guides as to what's "steep", "not so steep", "gentle incline" etc? Obviously it's subjective...

There are only two gradients: steep and not steep. Steep is where you can't maintain your preferred cadence. Not steep is everything else.

Consequently, it's gearing and fitness dependent.

Arguably there is a third category where you have to get off the bike and walk.

blorg

In cycling discussions % grade is almost always used.

Regarding horizontal distance/distance travelled the difference is tiny for any grade you are actually going to cycle up- only 0.5% for a 10% grade. So it can effectively be discarded.

Garmin GPS units record the altitude at a series of trackpoints, along with the time and location in latitude and longitude. They don't actually record the speed, grade, etc. in the log (although they do work it out for the display.) So all calculation on speed and grade is carried out by the application you load your log into; as you can imagine there are various degrees of smoothing possible.

Sample (this is smart recording, it records a trackpoint only when something changes, e.g. it will record less if you are doing a constant speed in a straight line: )

[HTML]
<Trackpoint><Time>2008-10-11T11:59:08Z</Time><Position><LatitudeDegrees>53.074362</LatitudeDegrees><LongitudeDegrees>-6.220225</LongitudeDegrees></Position><AltitudeMeters>228.622</AltitudeMeters><DistanceMeters>33115.480</DistanceMeters><HeartRateBpm><Value>147</Value></HeartRateBpm><Cadence>130</Cadence><SensorState>Present</SensorState></Trackpoint>
<Trackpoint><Time>2008-10-11T11:59:12Z</Time><Position><LatitudeDegrees>53.073919</LatitudeDegrees><LongitudeDegrees>-6.220512</LongitudeDegrees></Position><AltitudeMeters>224.065</AltitudeMeters><DistanceMeters>33168.875</DistanceMeters><HeartRateBpm><Value>147</Value></HeartRateBpm><Cadence>154</Cadence><SensorState>Present</SensorState></Trackpoint>
<Trackpoint><Time>2008-10-11T11:59:15Z</Time><Position><LatitudeDegrees>53.073554</LatitudeDegrees><LongitudeDegrees>-6.220747</LongitudeDegrees></Position><AltitudeMeters>221.989</AltitudeMeters><DistanceMeters>33212.426</DistanceMeters><HeartRateBpm><Value>149</Value></HeartRateBpm><Cadence>152</Cadence><SensorState>Present</SensorState></Trackpoint>[/HTML]

victorcarrera

Steep is where your cycling focus changes to preventing wheely, back wheel spin and heart attack.

niceonetom

-20% = :eek::D:pac::pac::pac:
-10% =
-5% =
0% = :rolleyes:
5% =
10% =
15% = :mad:
20% = :eek::mad::mad:

Raam

niceonetom wrote: »

-20% = :eek::D:pac::pac::pac:
-10% =
-5% =
0% = :rolleyes:
5% =
10% =
15% = :mad:
20% = :eek::mad::mad:

Best scale, EVER!

TinyExplosions

Raam wrote: »

Best scale, EVER!

Up there with the Blorg scale of toughness alright

scottreynolds

niceonetom wrote: »

-20% = :eek::eek::eek:
-10% =
-5% = :D
0% = :pac:
5% =
10% =
15% = :D
20% = :D:D

Corrected that for ya -- change the attitude its much easier then -- climbing is fun

Gavin

That's a good scale alright. You girly boy road racers ain't seen real steep

blorg

Gavin wrote: »

That's a good scale alright. You girly boy road racers ain't seen real steep

Haha, this is true. When I first got my MTB, I was thinking, who on earth would need 22-32 or whatever it was at the bottom. Then I went up/tried to go up a (according to my Garmin) 33% mud track. Needless to say I was in my bottom gear

sy

Where can I buy the Garmin that uses this system. niceonetom!

paddy's hill

stopped_clock wrote: »

Any guides as to what's "steep", "not so steep", "gentle incline" etc? Obviously it's subjective...

Anything up to 5% is ok.
Over 6% hurts
Over 10% is pain
Over 25% get off and walk

jautukas87

paddy's hill wrote: »

Anything up to 5% is ok.
Over 6% hurts
Over 10% is pain
Over 25% get off and walk

Every incline with West of Ireland's head winds doubles up in grade.

DirkVoodoo

I think this chap explains it pretty well:

One point that confused me was separating the idea of slope (b/a) from distance traveled (the hypotenuse, c).

Slope is b/a, rise over run — how much height you get when you increase width. How “steep” the hill is, so to speak. Unfortunately, the word “slope” makes us think of the side of the hill — but slope is really about height.

Distance (the hypotenuse) is about the side of the hill — how far you’ve walked. The “steepness” isn’t that important — you’re laying a measuring tape on the ground, which could be flat, vertical or upside-down. Does the length of a board depend on how you hold it?

But, in our man-made world, slope and distance are related because we often express locations in terms of “units East (x coordinate)” and not “units along a path”. So when a map says “go 1 mile due East” and you’re in front a mountain (large slope), you end up traveling a large distance (more than 1 mile). When on a flat road (zero slope), 1 mile East is simply 1 mile East. The bigger the slope, the more distance you must travel to “go 1 mile East”.

Again, we see that the Pythagorean Theorem is not just about triangles — it can convert slope (steepness) into distance traveled. Happy math.

Link

victorcarrera

jautukas87 wrote: »

Every incline with West of Ireland's head winds doubles up in grade.

+1 on that. I learned that lesson a few weeks back on the exposed west coast of Clare with a force 6 headwind and nowhere to hide.

Lumen

Distinctions between road length and horizontal distance travelled are pretty irrelevant, since A approximates H for small angles.

If you're cycling 10,000m along a 10% (5.7 degree) incline, the fact that you've travelled only 9,950m on the map is the least of your problems.

victorcarrera

Lumen wrote: »

Distinctions between road length and horizontal distance travelled are pretty irrelevant, since A approximates H for small angles.

If you're cycling 10,000m along a 10% (5.7 degree) incline, the fact that you've travelled only 9,950m on the map is the least of your problems.

But there is another consideration. After working so hard on that climb in most cases you can now use that stored kinetic energy to travel the next 10,000m with little or no effort to increase your map distance.

DirkVoodoo

Personally, I find descents nearly as tiring due to the mental strain and I also tend to tense up quite a bit when I am nervous on one.

scottreynolds

DirkVoodoo wrote: »

Personally, I find descents nearly as tiring due to the mental strain and I also tend to tense up quite a bit when I am nervous on one.

Girls blouse.

blorg

stopped_clock wrote: »

Any guides as to what's "steep", "not so steep", "gentle incline" etc? Obviously it's subjective...

Besides fitness/weight it also depends a lot on your gearing/how fast you wat to go up it. 5% can be torture in a race, you can go up 20% easily with lower gears and slowly.

stopped_clock

niceonetom wrote: »

-20% = :eek::D:pac::pac::pac:
-10% =
-5% =
0% = :rolleyes:
5% =
10% =
15% = :mad:
20% = :eek::mad::mad:

paddy's hill wrote: »

Anything up to 5% is ok.
Over 6% hurts
Over 10% is pain
Over 25% get off and walk

Cheers - Almost exactly what I was looking for!

blorg wrote: »

Besides fitness/weight it also depends a lot on your gearing/how fast you wat to go up it. 5% can be torture in a race, you can go up 20% easily with lower gears and slowly.

Yeah - I dig that, so was just looking for a rough guide. It's a bit like asking what a good average pace is - Could be anything, depending on the conditions.

stopped_clock

For a while there I was worried that defining gradient was going to turn into a helmet/red-light/cycle-lane debate between pro- and anti-hypotenusers.