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Understanding the Grading Charts

If we examine the chart to the left it is immediately obvious that it is valid for ride distances between 20 km and 100 km and moderate gradients between 6% and 7.5%.

Looking at the ride grades in bold integers ranged above the top diagonal and inner left hand axis, we see that it encompasses ride grades between 2 and 10. Note that grade 10 rides have no upper limit. The grade boundaries are delineated by straight lines descending to the right.

We also notice annotations for the percentage of the ride that is level ranged near the right hand margin. These annotations terminate a series of straight lines ascending from the left, each delineating a percentage of the ride that is level. In the wedge between these lines a separate annotation describes the same percentage in terms of the fraction of the ride that is climbing and descending.

The horizontal axis represents the straight line delineating all-level riding. So the horizontal axis also gives the Equivalent Level Distance for each ride grade.

We note that Grade 2 is shaded red. This means that the cctcc system does not allow for gradients between 6% and 7.6% on Grade 2 rides. Grades 3 and 4 are shaded yellow and annotated 6% Max indicating that the system only permits maximum gradients up to 6% on Grade 3 and 4 rides.

Example

A ride of 50 km has a steepest gradient of 6% with more shallow kilometres than steep ones. 50% of the ride is level. What is it's grade?

Solution.

• We locate the 50 km point along the base of the chart. A vertical red line has been drawn at that point.
• We move up that red line until we meet the 50% level point. (We may sometimes need to interpolate between tabled values).
• The intersection is in a right-descending panel. At the head of this panel we see the bold figure 7. So the ride is grade 7. The panel is not shaded yellow or red so this grade is acceptable.
• Drawing a line diagonally down to the horizontal axis we note that it intersects the distance line at the 80 km mark. So the Equivalent Level Distance of the ride is 80 km. A red line has been drawn to show this step.
• Now check the level speed for this grade by clicking here.

That's all there is to it!