I agree with not coasting. Riding in a pace line is like driving a race car: the most important thing is to be SMOOTH. Suddenly coasting is not smooth. Keep the legs moving, even if they're not dong anything, or if you must coast, reduce leg speed gradually. Suddenly stopping the legs often sends the wrong message to riders behind.

If you've ever ridden in a pace line on the track, you quickly learn that it's the smoothness of the rider in front of you that dictates how close you can get to his wheel. The smoother the rider immediately ahead, the closer to his wheel you can ride. When I get into an unfamiliar pace line, I'm sometimes an entire wheel-length behind the rider ahead just because I can tell he's not smooth. He suddenly starts coasting, thinking it's a cool way to control his speed without braking. If I can, I'll work my way around him.

Someone also mentioned not riding "in line." Where you sit in a pace line is heavily dependent on where the wind is coming from. The wind rarely comes from directly in front; usually it's from the side. I always move slowly from one side to the other (never overlapping the wheel ahead) until I find the zone with least wind resistance. This might stagger the line a bit, so I sometimes need to be on the windward side just to keep the pace line closer to the road edge, but in most cases the riders ahead will have no idea what the wind is doing, so I'm never out very far. In races, where we can use the entire lane, a small but savvy group will be side by side in an echelon when there's a hard crosswind blowing. But that's only for really experienced riders who know what they're doing.

If you are directly behind the rider in front, don't be afraid to move your upper body to peer past the rider(s) ahead. I often see road hazards coming up well before they're pointed out by riders up ahead. Get used to looking around, even when you're in the pace line. In other words, stop focusing on how close you are to the wheel ahead. In a team pursuit, it's really important. In a casual pace line, who cares? You're still getting wind protection even an entire wheel-length back.

And on descents, when the speed picks up, drift back and open up an entire bike-length or two. This is not only safer at the faster speeds of a descent, but if you have somebody ahead of you who can't corner, it puts you in the best position to slingshot past him as he's braking for the next turn. Conversely, if he's a really good descender, it gives you time to copy his setups for each corner (or to avoid his bike when he misjudges and bites it!).

Luis