They leave full of confidence after setting all sorts of national records at a hotted-up Invercargill velodrome.
No one impressed more than van Velthooven, who rode over the top of Australian Scott Sunderland to win the keirin.
The Commonwealth Games gold medallist normally beats up on New Zealanders for fun, yet he was also cleaned up 2-0 by Sam Webster in the sprint final.
BikeNZ high-performance director Mark Elliott was delighted by what he saw from his sprinters.
"What these guys have shown is not just where they are now on the world stage, but where they're going to be," Elliott said.
To illustrate how far they've come, this time last year Elliott and sprint coach Justin Grace were hopeful of getting Ethan Mitchell, the strong man of the team sprint, under-18s.
"Not only does he do that, but he rode 17.4s which is absolutely world class, and Matt Archbold went under 18s as well.
"This is the first time we've had not just one, but a team of world-class sprinters. It's very exciting for the future."
Before the Oceania champs, van Velthooven would have been looked at as the fourth sprinter behind Mitchell, Webster and Eddie Dawkins, but he is now on the verge of nudging his way past Dawkins.
"They've all made performance leaps ... but Simon has made massive gains," Elliott said. "He leaned up a bit and he's getting more powerful. He's just got to get a bit stronger.
"He's going to be phenomenal - he's the next Chris Hoy."
With just nine men's track spots available for London, Elliott has some hard decisions to make on the composition of the squad.
With Shane Archbold viewed as a medal prospect in the omnium, Elliott will not have the luxury of picking a rider for that event who can double as reserve rider for the team pursuit.
He will have to decide whether to carry a reserve rider for that team pursuit or sprint, or no reserves at all.
That's why it is important the riders maintain their form in Cali. With so much depth in the squad, as Hayden Roulston found out, now is not the time to drop your guard.
"To keep on that pathway to London, they have to be in form now," Elliott said.
BikeNZ officials will also be hoping the national record time of 3m 55s and some "off-the-charts" sports science readings from Aaron Gate will be enough to knock the Roulston controversy on the head.
If only life were that simple.
The sprinters might have put together the eye-catching performances in Southland, but it was the men's team pursuit who were the focus of attention.
They responded to the news Roulston had pulled out of contention for the four-man team by setting a blistering national record.
The guy who stood out, according to sports science readings taken during and immediately after the race, was Aaron Gate. That is significant, given that he is generally considered the rider who would have been sacrificed had BikeNZ acceded to Roulston's wish to come back into the team for London.
Roulston's is a curious case in that logic tells you BikeNZ has done the right thing, but the intangibles tell you something else.
The simplest way to sum it up is this: the track team must be in a very healthy position to be able to resist the claims of one of New Zealand's greatest cyclists with proven ability to perform on the biggest stage.
The squad for Cali
Shane Archbold (Timaru), Sam Bewley (Rotorua), Eddie Dawkins (Invercargill), Lauren Ellis (Hinds), Aaron Gate (Auckland), Joanne Kiesanowski (Christchurch), Ethan Mitchell (Auckland), Marc Ryan (Timaru), Jaime Nielsen (Hamilton), Jesse Sergent (Feilding), Alison Shanks (Dunedin), Simon van Velthooven (Feilding), Sam Webster (Auckland).
