Bicycling average speed is an important thing to know when joining groups. If you can’t keep up with a group speed, then you may feel embarrassed, the group may feel resentful, and you might get dropped in the middle of nowhere.

Rough estimates are:
* Average speed is about 80% of your flat&level speed.
* Add 15% for group speed vs solo speed.
* Subtract 10% for each consecutive hour of riding.
* Subtract 50% or more for uphill speed.
* Add 100% or more for downhill speed.

The easiest way to figure all of this out is to use a GPS device, a calibrated speed computer, or a smartphone app to figure your average speed for a route.