% Grade vs Degrees

[NewToy]

Anyone know what the difference between % of a grade as opposed to how many degrees the grade is? I always see the signs on the hiway saying 5% grade and it sure seems awfully steep.

Thanks,
John

 

[NewToy]

Anyone know what the difference between % of a grade as opposed to how many degrees the grade is? I always see the signs on the hiway saying 5% grade and it sure seems awfully steep.

Thanks,
John

 

[jinman]

I believe % grade is a measure of the rise to the run or how much the roadway rises compared to the length. If a roadway rose 1' for each 1' of length, that would be 100% grade (or the same as 45°). A 5% grade would rise 1' for each 20' of length or about 2-1/2°. When you are looking into a grade, your perspective is distorted. If you looked at the grade from the side, it would look a lot less imposing.

Disclaimer: There is a good possibility that my explanation is completely bogus, it's just my own understanding or lack of same. /forums/images/graemlins/smirk.gif /forums/images/graemlins/laugh.gif

 

[jinman]

I believe % grade is a measure of the rise to the run or how much the roadway rises compared to the length. If a roadway rose 1' for each 1' of length, that would be 100% grade (or the same as 45°). A 5% grade would rise 1' for each 20' of length or about 2-1/2°. When you are looking into a grade, your perspective is distorted. If you looked at the grade from the side, it would look a lot less imposing.

Disclaimer: There is a good possibility that my explanation is completely bogus, it's just my own understanding or lack of same. /forums/images/graemlins/smirk.gif /forums/images/graemlins/laugh.gif

 

[RobS]

Percent grade is just the rise over run. A 45 degree slope is 100% as the rise and run are the same. Your 5% grade is 5 feet in 100 which calculates to 2.86 degrees. The formula is Angle = ATAN (Rise/Run).

If you think 5% feels steep, try that 100% grade sometime /forums/images/graemlins/smile.gif

 

[RobS]

Percent grade is just the rise over run. A 45 degree slope is 100% as the rise and run are the same. Your 5% grade is 5 feet in 100 which calculates to 2.86 degrees. The formula is Angle = ATAN (Rise/Run).

If you think 5% feels steep, try that 100% grade sometime /forums/images/graemlins/smile.gif

 

[chili]

Here is how I figure 5% grade. 5/100=.05. Then take .05 and inverse tan which gives you 2.862405 degrees. Hope this helps.

 

[chili]

Here is how I figure 5% grade. 5/100=.05. Then take .05 and inverse tan which gives you 2.862405 degrees. Hope this helps.

 

[BubbaJr]

Here's a LINK to a grade calculator.

 

[BubbaJr]

Here's a LINK to a grade calculator.