As a Herbeauvilliers resident, I would say that there is plenty of cycling to be had in the area.
I have to admit that at the moment I probably go MTBing more than climbing.
Buthiers is only a 5 to 10 min ride away there are a few VTT circuits that start from there, thought you can pick some of them up closer to Herbeauvilliers.
see the "Téléchargez les circuits balisés" link via the "VTT et Vélos Funs" link on
http://www.base-de-buthiers.com/There are rules about which tracks you can use in the forest, ie keep off the narrow blue marked paths and keep to the wider paths.
There are some cycle paths marked out in the forest but I have yet to find a map.
If you really want there is a northshore place to the north which is about 1/2 hours drive away.
I wouldn't say though that bikes are a substitute for a car unless your used to bikeing everywhere inc sorting out food shopping etc