Hi, Jon, sorry don't accept that excuse. I've led a group on at least one occasion having forgotten my speedo and I just made sure the person riding next to me told me what we were doing
You were on the front when I gave up shouting
I agree that there is a bit of flexibility in the average speed but it doesn't exactly inspire confidence to move up to the next group when you think they'll be doing the same! My thoughts is that if you find it easy to keep up with say the 17s, you think about trying the 18s and so on...
Those of you who were cycling in the cycling heyday of the 50s may remember that the captain used to ride with a bugler beside him to give orders to the clubrun - any volunteers