It is Sunday night and my 17-year-old son Jamie is on his bike in the lounge room, riding on the rollers. A widescreen TV shows reruns of the Tour de France. Riders come towards him, flash past, two-wheeled terrestrials weaving through blocks of gold, lavender and stone.

He plans to have the ragged breath of a Froome, Cavendish or Quintana at his cheek one day, to feel the pure engine heat of other riders along the length of his body, to be part of the living organism of a peloton, stretching and snapping, morphing into a single cell.

I am all too aware of the fury that sometimes flares in response to the flash of bright Lycra.

In the two years that Jamie has been riding, he has had six crashes: 32,000-plus kilometres, inexperience, riding in the wet, mechanicals. Last Boxing Day he spent four hours in a country hospital under observation for suspected concussion. Another time he landed on his fingertips and chin after his chain came off and the downwards thrust of his foot met no resistance (there may still be road fragments in his chin that we didn't clean out properly). Each time he hits the road he rips off old scars and his faithful body replaces them with bigger purple ones.

My biggest fear is that the next crash will be serious. Not just months of dressings on hips and elbows. Not just broken collarbone, fractured jaw.