How does this work?
Hill walkers sometimes use a rule of thumb called
‘Naismith's Rule’
to estimate how long a route will take.
The calculation uses total distance, and the amount of height gained and lost to
give a rough estimate of how long a route will take. It's far from perfect, but better than nothing.
There's no generally accepted equivalent of this formula for offroad biking.
However, using published calculations and our own
observations we have written a calculation that will estimate how long an offroad bike route may take.
Information about the route is used to further refine the calculation.
Although we have filled in the details for the Castle Howard route, you can use your own figures for any route.
Route Details
Adjustments
How does this work?
The average road and off road speed are used to calculate the time in minutes:
Time = offroad distance x average offroad speed + onroad distance x average onroad speed.
Then, the additional time for climbing is added in, at 60 minutes per 500 meters.
As going downhill is faster than riding on the flat, we remove 60 minutes per 2000 meters.
We assume the route is a loop and so total climb will equal total descent.
Optionally, 10% extra time is added (or subtracted) for every point of difficulty above (or below) 2.5.
And finally, extra time is added or subtracted depending on your fitness rating.
Limitations
There are some limitations you need to bear in mind:
- The calculation only estimates your 'rolling time', so you will need to
allow extra time for resting and any any possible problems
- Difficult trail conditions, for instance deep mud, will dramatically lower your average speed
- A route which starts and ends in different places will have different figures for total climb and descent, so the calculation will not be accurate