"There's a subtle difference in the two roles but not a big one," Tander told the Weekend Herald from Mount Panorama.
"My role is not to take as many risks and solidify the position we're in. If the race is going smoothly that's the way you have to attack it - be solid, be fast, be steady and take minimal risks.
"If the race has gone off the rails a little bit and we need to get ourselves back into position then I can step up and take a few risks. There is no point me just cruising around at the back of field being steady if we have to get on with it.
"If we're in good shape I don't take risks. If we need to get a move on then my role becomes closer to what the main drivers is."
Matching primary and co-drivers is an art form with lots of moving parts. It's not just a matter of picking someone who is fast and chucking them in the car - there's a compatibility issue that needs a lot of thought.
"The ideal wishlist is that they are similar physically, similar temperament, similar driving styles and like similar things from the car," said Tander. "You don't always get that though, so in the lead up to the race you work on team work.
"When I was a primary driver it would be no good if I was under the lap record and my co-driver wasn't comfortable and couldn't maximise the car.
"You're only as fast as the average time of the combination. Having had co-drivers before has helped me transition to being a co-driver. Shane and I have similar driving styles and like the same feel from the car."
This year sees probably the best lineup of co-drivers in the history of the event. With the likes of recent full-time drivers Tander, Lowndes, Lee Holdsworth, Chris Pither, and a heap of very quick Super2 drivers, the pace won't slacken much when the primary drivers hand over the keys.
"It seems to get stronger every year," said Tander. "It's great for the race. When people saw Shane and me together and Craig and Jamie they knew they had to also find strong combinations.
"It looks good and makes for a better race. If all the co-drivers are in the car at the same time it's going to be pretty full on. It'll be cool."
While not quite the build-up of the Indianapolis 500, teams are at the Mount Panorama circuit for nigh on a week. That's a lot of time to be thinking about how the race will pan out on Sunday.
"Everyone loves the place. I've been fortunate to have had some success here over the years. I really enjoy the place and the challenge of the whole week," Tander said.
"There's the whole lead up to practice and qualifying and I enjoy the teamwork aspect of that. And then you have the race and all that entails."
This will be the fourth time at Bathurst that Tander has driven with a New Zealander - Pither in 2018 and van Gisbergen the last three years.
"Fourth in a row and some pretty good finishes," he laughed. "You guys are invading our country."