Sylvain Chavanel, on the Rivet
© Tim De Waele
On The Rivet...
Very similar to Full Gas, this term means basically to be riding at full speed, and maximum power. When riding at maximum power output, most riders tend to sit as far forward as possible on the saddle, trying to get as much power from their thighs as possible. The old leather saddles had a single rivet attaching the saddle leather to the saddle frame, hence the term, On The Rivet.
Soigneur...
An all-encompassing term that is used less and less these days. It’s used for a non-riding member of a cycling team who is responsible for preparing food, bottles, giving pre- and post-race massages, possibly driving vehicles and generally making sure the riders are content. In days gone by many of the top pros had personal soigneurs. In the days before the internet and training guides, the soigneur was something of a mystical figure, doling out race advice, special vitamins (sometimes very ‘special’) and secret training techniques.
Eddy Merckx's soigneur, Guillaume Michiels, was also Merckx’s regular drinking partner. After a few too many Belgian beers, the pair would be out on the roads the next day to "to ride the poison out of his system."
These days many of the jobs done by a single soigneur are done by specialized individuals.
Chain Gang...
This is the term used for a group of cyclists who are out riding together in formation, with one rider swinging off the front and heading to the back, to be followed by the next rider. In Europe, riders meet for Chain Gang rides midweek, to practice for weekend races.

(c) Tim De Waele
Roleur....
A cyclist who is suited to riding on the rolling hills, a strong, powerful cyclist who can maintain high speeds for long periods.
Tony Martin (HTC-Highroad) a perfect Roluer. (c) Tim De Waele
Wheel Sucker...
If anyone ever calls you a Wheel Sucker, trust me, it is not a compliment. It is a term used to describe someone who sits on the back of another rider’s wheel all day, and never comes to the front to do his fair share of work. Hence, he sucks onto the wheel in front. He saves his energy all day. Wheel Suckers often go on to win races, but also seem to get more than their fair share of abuse. Funny that.
Jose Rujano on Contador's wheel, but Rujano didn't win. (c) Tim De Waele