KEY POINTS:
When Sarah Walker was asked how she figured the first BMX Olympic final would pan out, the world No 1 rider was forthright.
By her count, Walker reckoned the three medals in Beijing - given an even run of the race - would be split between four riders. Two are French, Anne-Caroline Chausson and Laetitia Le Corguille, ranked No 2 and 3 in the world. She put herself in the mix and liked her prospects.
But of Walker's rivals, the most interesting, and the biggest threat, is Britain's Shanaze Reade.
When Walker's Australian coach Grant White walked out on the Bay of Plenty rider last year, it was to take up with Reade.
Walker says she's over it, although admitted it hurt at the time. So understandably that will add an edge to the contest between the pair.
However Reade also provides a compelling story of making good from a highly unpromising start in life.
Born to a Jamaican father, who shot through on the family soon after Reade was born, and a 17-year-old Irish mother on a tough council estate in grim Crewe near Cheshire.
Reade came under the guidance of a colourful character called Bob Field, a Rastafarian who ran the local BMX track.
She hopped on a BMX bike for the first time at 10 with Field's encouragement. She was British senior champion at 13 and has now bagged three world titles, including this year's Olympic class event in China in May, when Walker finished third.
Walker is world No 1 rider by dint of her overall performances in the year.
The contrast is marked. Walker is slim, fresh-faced; Reade, a year younger at 19, is a tough, no-holds-barred person with a stud through her top lip, who is armed with a fierce desire for success.
Her website until recently described her as "a badass chick who kicks guys". She is happy for the world to know the circumstances of her early life.
"I want the public to know my story because I didn't have the best of upbringings and that might inspire a few kids," she said recently.
Gifted and versatile enough to have won the world track cycling teams title for Britain - "it's all pedalling, isn't it?" - Reade craves success as if to prove it can be achieved with the right approach, no matter the background.
And she will have an emotional element to spur her on when the women's event begins tomorrow.
Field died this year.
It's a story vastly removed from Walker's upbringing in Kawerau and Whakatane. The clash should prove fast - each race takes no more than about 40 seconds - furious and exhilarating.
New Zealand's male representative, Marc Willers, has had a look at the course and likes what he sees.
Willers, 22 and from Cambridge, is ranked No 5 going into the Beijing race.
It is a big deal for the sport making its Olympic debut. But Willers is doing his best to treat it as just another race, albeit with plenty riding on the outcome.
