Show both km to miles on screen. During a group ride (especially those with 300+ riders) some use miles and some use kilometers. When spread out some folks indicate they are at a certain km and otters at certain miles. If you are used to one and not the other it is hard to determine if they are ahead or behind you. Having this could help some folks get back together if they know both distances. This was the case today with the pack ride 300+ riders got spread out early. when the ride leader or ride trailer has issues and tries to catch back up etc.