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  1. #1
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    hill gradient/percentage

    seen a thread on here before for working out the percentage of hills and dont seem to be able to find it as i want to try and figure out the % of hills around my area where i cycle.i think it was that a 100% gradient was actually a 45 degree incline,which if correct makes a 10% hill 4.5 degrees.am i correct in thinking this?

  2. #2
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    Put your rides into map my ride and this will give you climb info.

  3. #3
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    A 10% grade is 5.74 degrees. Slope - Degree, Gradient and Grade Converter
    Last edited by testpilot; 01-13-2013 at 03:11 PM.
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  4. #4
    wim
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    To find percent grade from degrees, use the calculator at the link, top of the page. Select "Angle" for input, type in the angle in degrees, hit 'calculate' and read the rise / run figure.
    Gradient, Slope, Grade, Pitch, Rise Over Run Ratio Calculator

  5. #5
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    Gradient is vertical rise divided horizontal run, expressed in percentage.
    100% is 100/100, or 100 units of vertical rise divided by 100 units of horizontal run, which is 45 degrees.
    10% is 10/100, or 10 units of vertical rise divided by 100 units of horizontal run, which, as correctly stated by testpilot, is 5.7 degrees.
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  6. #6
    acg
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    2.0%
    1 degree

    4.0%
    2.3 deg

    6.0%
    3.4 deg

    8.0%
    4.6 deg

    10.0%
    5.7 deg

    11.0%
    6.3 deg

    12.0%
    6.8 deg

    13.0%
    7.4 deg

    14.0%
    8.0 deg

    15.0%
    8.5 deg

    16.0%
    9.1 deg

    17.0%
    9.7 deg

    18.0%
    10.2 deg

    19.0%
    10.8 deg

    20.0%
    11.3 deg

    25.0%
    14.0 deg

    30.0%
    16.7 deg
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  7. #7
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    Recall high school maths.

    tan (deg) = Y/X

  8. #8
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    When did math become maths?
    ... 'cuz that's how I roll.

  9. #9
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    Quote Originally Posted by looigi View Post
    When did math become maths?
    When you speak the queen's english, rather than 'merican

  10. #10
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    Quote Originally Posted by looigi View Post
    When did math become maths?
    It's a British thing. I'm sure they'll be on shortly to point out that it was 'maths' before it was 'math'.

    Edit: Oops, looks like the Redcoat beat me to it.

  11. #11
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    For "our" purposes, if you climb 10' for every 100' you ride, you are on a 10% climb. It's not exact to 3 decimal places but you probably can't measure that close anyway.
    And at the grades we climb, it will do.

  12. #12
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    Quote Originally Posted by Alfonsina View Post
    Put your rides into map my ride and this will give you climb info.
    ridewithgps.com is much better. It shows distances and grades as you draw the route, and it's easy to undo and try a different road. mapmyride wants to average out the grades too much, and wants to be your social media site.

    Here's an example from a route I created in ridewithgps.com. I just hover the cursor over the red elevation graph and it shows the grade and elevation at that point. The blue dot on the route map is that location.

    Dragging a section of the graph will give average grades, total elevation, and distance for that part of the ride.

    This is the Terrain option selected from the top right pulldown Map list. It's zoomed all the way in, and each contour line is 40 feet of elevation.

    All the mapping web sites use elevation data points. So locations in between the known points need to be estimated. On steeper climbs, the exact elevation of a spot on the road might be off a few feet, enough to affect the local grade calculation. But usually it's quite accurate.


    Last edited by rm -rf; 01-14-2013 at 08:30 AM.

  13. #13
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    If you want to go measure a grade yourself:

    Use a 2 foot or 4 foot level. Mark a stick (for instance, a paint stirrer) with grade percentages. Put one end of the level on the uphill, hold it level, the read off the grade on the stick held vertically at the downhill end of the level.

    For instance, a 2 foot level:
    2%: 24 inches * .02 = .48 inch
    5%: 24 * .05 = 1.2 inches
    10%: 24 * .10 = 2.4 inches

    (It's interesting to see just how shallow that appears, compared to the effort to do the climb.)

  14. #14
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    Quote Originally Posted by rm -rf View Post
    If you want to go measure a grade yourself:

    Use a 2 foot or 4 foot level. Mark a stick (for instance, a paint stirrer) with grade percentages. Put one end of the level on the uphill, hold it level, the read off the grade on the stick held vertically at the downhill end of the level.

    For instance, a 2 foot level:
    2%: 24 inches * .02 = .48 inch
    5%: 24 * .05 = 1.2 inches
    10%: 24 * .10 = 2.4 inches

    (It's interesting to see just how shallow that appears, compared to the effort to do the climb.)
    I will hand out 1 Official Certificate of Internet Achievement to anybody who posts up a picture of themselves doing this.

  15. #15
    wim
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    Quote Originally Posted by ratherBclimbing View Post
    I will hand out 1 Official Certificate of Internet Achievement to anybody who posts up a picture of themselves doing this.
    Where do I pick up my certificate? Many years ago, I went around the general area and established maximum percentage grade for many climbs by doing exactly what you described, see photo below. I put together a little pamphlet on local climbs, which was well received. No one at that time had Garmins or other grade-measuring devices.
    Last edited by wim; 01-14-2013 at 11:32 AM.

  16. #16
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    Hah! Well played. A deal is a deal. I'll get to work on that cert tonight.

  17. #17
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    Quote Originally Posted by rm -rf View Post
    ridewithgps.com is much better. It shows distances and grades as you draw the route, and it's easy to undo and try a different road. mapmyride wants to average out the grades too much, and wants to be your social media site.
    I agree the interface on rwgps is far nicer to use (at least in my experience) but keep in mind if you're mapping a route, all the elevation is based on public DEM data, which has a resolution typically around 30 meters and does not account for road grading/leveling in hilly terrain so the grades it will produce are going to be pretty far off from actual road conditions.

    It's going to be better to look at actual recorded elevation data over a route (from a garmin, for example) to see the actual grades.

  18. #18
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    thanks fellas a lot of good info there thanks for taking the time to answer.

  19. #19
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    Quote Originally Posted by nhluhr View Post
    I agree the interface on rwgps is far nicer to use (at least in my experience) but keep in mind if you're mapping a route, all the elevation is based on public DEM data, which has a resolution typically around 30 meters and does not account for road grading/leveling in hilly terrain so the grades it will produce are going to be pretty far off from actual road conditions.

    It's going to be better to look at actual recorded elevation data over a route (from a garmin, for example) to see the actual grades.
    My 705 garmin (using an accurate barometric elevation sensor) usually matches the ridewithgps calculated grades.

    But traversing steep slopes can throw off the ridewithgps calculation pretty easily. But then you see 6%, 6.2%, 7.3%, 13%, 9%, 7.1% and can discount the non-existent bump in the middle.

    There's a few road improvements near here in Indiana where they cut a new road into the hill, but the maps think it still climbs the old very steep grade.

    And it doesn't know about the tunnels in the Blue Ridge Parkway, so it shows a sudden steep bump over the top of the mountain instead of an easy grade through the tunnel.

    In general, I get very few grade surprises from ridewithgps routes.

  20. #20
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    Quote Originally Posted by rm -rf View Post
    My garmin usually matches the ridewithgps calculated grades.

    But traversing steep slopes can throw off the ridewithgps calculation pretty easily. But then you see 6%, 6.2%, 7.3%, 13%, 9%, 7.1% and can discount the non-existent bump in the middle.

    There's a few road improvements near here in Indiana where they cut a new road into the hill, but the maps think it still climbs the old very steep grade.

    And it doesn't know about the tunnels in the Blue Ridge Parkway, so it shows a sudden steep bump over the top of the mountain instead of an easy grade through the tunnel.

    In general, I get very few grade surprises from ridewithgps routes.
    Strava seems to match my Garmin as well. I don't actually do point comparisons, but I'll have on a gradient field while climbing to get an idea of what grades I'm on and do a zoom through on Strava when I'm at the computer. It's certainly in the ballpark, which is all I really care about. MapMyRide on the other hand seems to produce all kinda of funky data.

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