Taking part in The CatWalk Spinal Cord Injury Trusts nationwide fundraiser, he will pilot a stint from Oamaru to Queenstown on Sunday in the purpose-built three-wheeler.
Having driven a three-wheel adaptive car in England, which was "only about 500cc", and been a pillion on friends' motorcycles, he was excited about the chance.
"This is going to be the most fantastic experience."
And this is no ordinary trike.
Featuring a BMW motorcycle's front end, it incorporates a platform that riders can roll their wheelchairs on to via an automated access ramp.
The accelerator, brakes and gears are all hand controlled.
"It's been designed so everything can be operated from the handlebars," Mr Marrable (52), a disability information consultant, said.
The 83hp two-cylinder machine has room for a passenger and most importantly "it looks mean", Mr Marrable said.
Named the Conquest, it was developed in England by Martin Conquest company founder Alan Martin, who started work on the project when his son became disabled.
Retailing for 19,948 ($NZ53,230), the model that arrived in New Zealand was the first of its kind in the country and started CatWalks Conquest Tour in Auckland on October 29.
Aiming to raise money for scientific research to enable spinal cord injury victims to walk again, the bike trip will enlist 17 paraplegics to ride the Conquest down through to Invercargill and back to Christchurch on Thursday.
It will then be auctioned off, with proceeds going to the CatWalk Trust.
Trust manager Meg Speirs said the riders who had completed their stints were "just buzzing" about the experience.
Participants set up profiles on the website www.fundraiseonline.co.nz and had pulled in $37,000 so far, she said.
Mr Marrable will wheel on board on Sunday for a 9am departure from Oamaru's Armada Motor Inn.
He will stop off at Omarama's Wrinkly Ram Caf from 10.30am to 12.30pm before touring through Cromwell, finishing up at Queenstown's wharf about 4.15pm.
He hoped motorcyclists in the areas he passed through would accompany him partway and was thankful to a "mate" riding with him right through to Queenstown.
Certainly not one to shy away from life, he is a fifth dan black belt in karate and was in the New Zealand development squad for Paralympic snow sports until an injury forced his retirement.
