PSA - Slope

"HammerheadFistpunch" (hammerheadfistpunch) 10/17/2013 at 19:14 • Filed to: PSA, TEch, HHFP

13

23

I've seen this pop up a lot recently, so I thought I would just clear the different between grade and slope.

Percent Grade is a percent and is calculated simply using Rise over Run.

grade = (rise / run) * 100

So, as you can see, by these charts, 100% grade is 45 degrees, not 90. Now for references.

For skiers, a black diamond run is usually 28-35 and double black is 30-40 degrees.

(this one is from 35-38 degrees)

This is an 80% slope (37 degrees)

Just wanted people to have the info. Enjoy.

pdthedeuce > HammerheadFistpunch 10/17/2013 at 19:18

1

so , if I get this right , if you drive forward 100 feet and the elevation rises 100 feet , that is a 100% grade ?

desertdog5051 > HammerheadFistpunch 10/17/2013 at 19:18

0

So, does that mean that my statement of a 6% grade is a drop of 6' per 100' of travel is not accurate?

HammerheadFistpunch > pdthedeuce 10/17/2013 at 19:20

0

yup, but only a 45 degree slope.

pdthedeuce > HammerheadFistpunch 10/17/2013 at 19:21

0

gotcha . thanks for the knowledge .

anonsagainstanonymous > HammerheadFistpunch 10/17/2013 at 19:21

0

so the sign should have read %

HammerheadFistpunch > desertdog5051 10/17/2013 at 19:23

1

6 over 100 is 6%. Its accurate.

Mazarin > HammerheadFistpunch 10/17/2013 at 19:23

2

So, what's Professional Grade?

HammerheadFistpunch > anonsagainstanonymous 10/17/2013 at 19:24

0

Exactly.

HammerheadFistpunch > Mazarin 10/17/2013 at 19:25

0

Im not sure, but I'll bet Mike Rowe doesn't have anything to do with it.

davedave1111 > HammerheadFistpunch 10/17/2013 at 19:33

2

Perhaps I can clarify it a bit.

Percent literally means 'per hundred'. Another way to say 'per' is 'for each'. So percent just means 'for each hundred'. When we say the road goes up 100%, we're saying it goes up a hundred 'for each hundred' (it goes across).

On second thoughts, maybe I can't clarify it a bit.

Lachlan - #ForzaJules > pdthedeuce 10/17/2013 at 19:50

2

Just to clarify, the distance travelled by the car in order to achieve a 100 foot increase in elevation on a 100% grade would actually be 141 feet. Yes, you would move horizontally 100 feet, but that would not be the distance you truly drove the car.

pdthedeuce > Lachlan - #ForzaJules 10/17/2013 at 19:53

0

right ... I didn't quite phrase it properly , but you got what I meant .

Lachlan - #ForzaJules > desertdog5051 10/17/2013 at 19:54

0

Not quite. Look at my reply to pdthedeuce.

Lachlan - #ForzaJules > anonsagainstanonymous 10/17/2013 at 19:57

0

Technically the percent grade is undefined because you can't divide by zero. x/0

Lachlan - #ForzaJules > HammerheadFistpunch 10/17/2013 at 20:02

0

Where is that ski run? It looks really familiar.

desertdog5051 > Lachlan - #ForzaJules 10/17/2013 at 20:04

0

I assume that the 100' of travel is based on a level 100'. If you factor slope for your 100', then it skews the figures as 100' of a slope is not the same as 100' of forward travel. Right or wrong?

Lachlan - #ForzaJules > desertdog5051 10/17/2013 at 20:07

1

You're right. If you're talking only about the forward travel then your statement was accurate. It's just that since the car or other object is traveling along a slope it will move a distance greater than 100'.

HammerheadFistpunch > Lachlan - #ForzaJules 10/17/2013 at 20:12

0

Svowbird

Lachlan - #ForzaJules > HammerheadFistpunch 10/17/2013 at 20:14

0

That's what I thought! I ski there all the time

blackchair > HammerheadFistpunch 10/17/2013 at 23:59

0

informative! Also makes me want to stay away from blacks...

blackchair > davedave1111 10/18/2013 at 00:00

0

Actually, it does make sense me more because of this. The obvious is usually not very obvious.

HammerheadFistpunch > blackchair 10/18/2013 at 00:11

0

they aren't so bad...me myself, I like a little slope

corvairsomeday2 > HammerheadFistpunch 10/18/2013 at 09:32

0

Thank you. I've known this for a while, and it's nice to hear it preached!