"The Mongol Rally means we get to fundraise for our charities which is quite big for us," Knuvers said.
Arohanui Hospice and Parkinson's New Zealand are charities close to their hearts.
Knuvers' dad died in the care of Arohanui Hospice and the brothers' mother is suffering from Parkinsons so Knuvers is hoping they can raise a tidy sum for the charities.
"It's massive that we can do that through the rally," she said, although she is more used to snowboarding and sailing.
Hughes is no stranger to 'toughing it', raised with a rifle in her hand and a fleece on her back.
She said she has had a number of adventures, including being dropped in the middle of the Swedish Lapland with nothing but the clothes on her back, summers at a fishing lodge in northern Canada or chasing cattle in the outback.
Hughes will be the one the group calls on if they run out of food.
During the rally there is no backup, no support and no set route, just the four of them in a tiny car they bought from a scrapyard.
The Mongol Rally website describes the adventure as "getting lost, using long-neglected wits, raising shedloads of cash for charity and scraping into the finish line with the vehicle in tatters and a wild grin smeared across grubby faces".
There are three rules for the rally - you can only take a small vehicle, you're completely on your own and you've got to raise £1000 for charity.
The rally also comes with a warning that the risks involved cannot be overestimated: 'Your chances of being seriously injured or dying as a result of taking part are high.
Individuals who have taken part in the past have been permanently disfigured, seriously disabled or lost their life.'
The rally will cost the group $10,000 and they are hoping that people will help offset this cost as well as donate money for the charities.
Knuvers said sponsorship can range from monetary donations to donations of items such as tents, sleeping bags or product donations.
"Whatever you do/make/sell there is a good chance that somewhere between London and Ulaanbaatar, we will find a use for it," she said.
Brands that support their rally will be advertised on the side of their vehicle.
If you would like to support the group you can donate through their Give a Little page -1hellofajourney.
The rally is expected to take about four weeks. Follow their adventures on Facebook: Kiwis Crossing - Mongol Rally 2017.