Riding in a pack is one of the most essential skills that a rider can develop. I think it is also one of the hardest to do right. Once a rider develops a rudimentary sense of pack riding, it will open a lot of new opportunities for them. Three key skills are signaling, drafting, and rotating.
Go faster by sharing the work...
If you want to go faster, and who doesn’t, one way is to share the work. Pack riding allows the riders on the front to do more work and the riders on the back can draft and conserve their energy and strength for their turn. By sharing the load, a stronger rider can do a little more work and a weaker rider can do the share they are able to muster. I have ridden with several strong riders, and on a windy day they are more than happy to do more work. If a group works well together, it is a thing of beauty. If the group does not work well together, a group ride can be extremely frustrating and even dangerous.
Because a group is moving quickly down the road, it is essential that those in the lead signal to those behind to warn of any stops or dangers on the road ahead. This signaling must be done safely with one’s hands, because it is next to impossible to hear a rider at speed clearly as he or she attempts to call back to the riders behind them.
When you are tucked in a tight group, one’s ability to see the road surface is compromised, so it is essential that the lead riders provide feedback by pointing to holes, glass, manhole covers, debris, and anything else that the group should avoid riding over. The lead rider should point firmly at the object with one hand still on the bars, and all the riders behind should safely signal and relay the information back. If a stop is imminent, a closed fist behind the lead rider’s back tells everyone to get ready to stop or pumping an open hand downwards can signal the group to slow down a smidgen. A tap on one’s hip can indicate that there is a parked car, pedestrian, or other possible hazard ahead. The lead rider taps left or right to indicate on what side the hazard ahead is on. If a group is most of the way through a light and/or traffic is clear, a tomahawk-like chop pointing straight ahead can indicate that the group can go through the changing light or four way stop safely. The group size, skill, and traffic pattern will determine when it is appropriate to do this or not. Obviously, turns should be relayed back to the group in advance as well.
These signals can change from group to group, but these are uniform, at least in our area. When you begin a ride, make sure your group has their basic signals straight. Sort of like in baseball between the pitcher and catcher. No one wants the curve when they are looking for the fastball.
Lastly, I think it is essential that one can maintain their speed and direction safely while indicating. If you cannot point to an object without swerving, you might be in over your head. Consider whether the group you are in is the right one for you or not. Of course, there will be times when unforeseen hazards go unsignalled, but these should be few and far between. You will get comfortable with signaling as you practice, but if you just cannot switch to riding one handed, you need to consider this and take the proper precautions.