I'm with JRT on this one. Spare a thought for the ozone layer Jens and search for an alternative to assist your velocipede meanderings. I feel sure that Karl von Drais, when he first appeared on the streets of Mannheim would never have resorted to consuming vast quantities of gas-producing veg in order to facilitate his progress. Asphyxiation of the onlookers would have killed off any prospect of his contraption gaining popularity.