2024 RDI and Details
Purpose
To allow riders to use an objective comparison of the difficulty of one route to another. This should help riders select a route suitable to their ability.
How it Works
For each route, the distance and elevation change are entered into a formula which calculates the route difficulty index (RDI). Elevation change is weighted more heavily since this has a larger impact on difficulty than distance alone. Since this method only looks at the overall elevation change for the entire ride, it will not necessarily “catch” an individual steep hill on an otherwise flat route.
How to Use it
When considering a new route, compare its RDI to the RDI of routes you are already familiar with. If it falls within the range of those routes, you can expect that it will have a similar difficulty. There is quite a bit of overlap in the RDI values for the FCC A-E routes, so it’s always wise to check to make sure the RDI for a particular ride falls within your personal comfort level. For instance, if you are normally a C rider that can handle all the C routes, you can consider some of the flatter A/B routes that sometimes have a RDI in the range of the more difficult C routes. On the other hand, if you concerned about struggling on some of the rides, this index will give you an indication that an upcoming ride might be too hard so you can pick an easier level. Keep in mind that weather such as wind or extreme temperatures can have a dramatic effect on the perceived ride difficulty and should be considered as well.
How Not to Use it
This tool should be helpful in comparing routes within a relatively similar range. So, it would not be accurate to say that a route that has a RDI three times as high as another route is three times harder or would simply take three times longer to complete. Also, the scale was set at around a range of 0-100 based on the current routes we use. But it is open-ended and a new route could exceed a RDI of 100.
