Thanks for that guys, I'm beginning to put a mental picture together...... I guess the fact I ride on my own makes it harder to understand things that perhaps club riders would experience every week.
Two points that I'd like to understand..... in a brakeaway group working together.... the guy in front is "doing the work", by that I understand that he is doing probably his fastest for 30 - 60 seconds BUT surely the guys behind are also working very hard to keep up with the pace ( how much easier is for the riders not in front) ..... not having the experience I find it hard to imagine the effort is much less. Maybe by relaxing a bit from the from position to the last in the group is enough to recover..... I think in this case I like to compare heart rates to understand what is happening to those riders.
The other point is: when I heard that a team brings a sprinter to the front.... how do the team mates help the sprinter? Surely the effort to get to the front is the same for all in the team.
I really would like to see in numbers how much effort takes to ride at the front of a peloton and how much at the back.... probably that would be easier to understand.
Should I assume most riders have very similar endurance?
A team of 9 usually consists of a team leader, a sprinter as alluded to, and 6 to 7 domestiques. These domestiques, some very good riders, sacrifice their own efforts to help their star man (leader), either win the entire race or a stage, or a jersey. These goals determine everything.
To add to what has been said already, the peloton (the herd) is quicker because the majority of riders are slipstreaming. In a large group this effect also creates momentum. Think about a group of riders in a line - the front man (or woman!) takes the hardship because it is the front rider(s) that take the wind head on. More specifically, air is made of particles that are disrupted when a bicycle wants to cut through it at speed. This causes drag. So, irrespective of a strong wind that makes it even harder, the front rider(s) are making the most effort. This is why a breakaway work together - they take turns in front of the small pack whilst the others slipstream their effort.
So, when a team brings a rider to the front they are not only jostling for position they are also protecting that rider's energy by making sure that he doesn't expend unnecessary energy at the front of the team, before he wants to break. When he's ready to go for glory the domestiques might be up, but that is unimportant because they have already done their job like a midfielder in football who delivers the killer ball to the striker who finds home.
In terms of endurance it has to be asked, endurance for what? Most riders have a speciality but it is those with an all round ability who win events like the Tour De France. Take Cavendish as an example, brilliant sprinter that he is he won't ever win the Tour because his victories, stunning as they are, are won by the ferocity of a sprint and cleared by margins of sometimes less than a second. (When AccountantPete talks about the small breakaway groups during flat stages of significant riders from teams with no sprinters, they are trying to breakway from riders like Cavendish because they know if it comes to a finish line sprint they won't stand a chance).
Compare this with an exceptional mountain climber like Miguel Indurain during the 90s and Marco Pantani who could make exceptional (time) gains in the mountain stages, but lose very little on the flat stages too and you have a potential all-round winner of a tour, as opposed just a stage or a jersey.
There are also the individual time trials and the team time trials TTT (usually early on in a tour to make sure each team have not lost riders), where a team of nine riders work together much like a small pack but without the potential jostling for position. Here, it is the 5th rider whose time is taken as the basis for the overall time.
