Apologies as slightly off topic: With reference to Graham's bike . . . 'stem bolt had been loosened in order to allow the handlebars to be turned to lay flat on the roof.' . . . and speaking as an old 'biker' I would like to suggest all of you who ride - on towpath or further afield check your stem bolt and ensure they are only EVER tight enough to stop the steering wobbling - it should always be possible to [relatively] easily twist the handlebars around [with the front wheel between the legs]. This will prevent you receiving all manner of leg /knee injuries should you ever take a tumble - as I often did in my racing career. Many bike shops are over enthusiastic in tightening stem bolts , so don't leave it to them - do check for yourself. This fortuitously means you can turn them easily for stowage on your nb, in your shed etc.
Trust that saves a few injuries Tony
