I'm doing a 100 mile sportive - is it ok to tag onto a group of riders who I don't know? Is there an etiquette to his? I'll have plenty of group riding experience by the time of the event .
if you're friendly and happy to share the time on the front, most people will be fine. always polite to ask though
for most sportives the group will consist of people that do not know each other anyway. agree with above - if group is rotating well, then dont shirk your hard time and noone will mind whatsoever.