Autobus

[cycling] The autobus or the gruppetto is in bicycling terminology the name given to the group of cyclists in a road cycling race who form a large group behind the leading peloton. The autobus forms on mountain stages when non-climbers fall off the back of the peloton during the climb. Gradually some riders fall off the back of the peloton ...
Found on http://en.wikipedia.org/wiki/Autobus_(cycling)

autobus

This stage racing term (the Tour de France is the most famous stage race) is used for the group of racers riding near the back who work together to finish the stage just before the time limit expires.
Found on https://www.encyclo.co.uk/local/22515

autobus

[French] in stage racing, group of slow climbers left behind on a mountain, riding together to finish within time limit; also grupetto, and laughing group
Found on http://bikecult.com/bikecultbook/glossary_english.html
No exact match found