Cross, 49, will be doing it to help a mate, Jason 'Buddy' Miller, a former Taree local now living in Sydney, who had his hands a feet amputated earlier this year after contracting a bacterial infection. At one stage he wasn't expected to live.

Cross is hoping to raise $5500 to help Buddy with ongoing medical costs. 

"I went to school with Buddy and we all lived together in Newcastle when we were going to uni or TAFE,'' Cross explained.

All riders in the event can nominate a charity they wish to assist. Fryatt, 34, has never met Buddy, but thinks he'll also fund raise for him.

Initially Cross, who is president of the Manning Valley Cycle Club, hoped to arrive in Sydney on Wednesday, April 10.

"That's my 50th birthday,'' he said.

"But a Wednesday didn't suit everybody … they want me to get there on the Saturday (April 13), so we can get on the drink and celebrate my birthday. So I might have to double back a bit.''

Fryatt has done a bit of bike touring overseas, but he quickly adds nothing of this magnitude.

"I'm hoping to get to Sydney in 18 days and to do so I'll have to ride 300kms a day,'' he said.

Cross initially planned for 22 days, but that's now out to accommodate his 50th celebrations.

The ride is totally solo. 

Cyclists have to camp rough when and where they can. They have supply their own food and medications. Riding in groups is also discouraged.

"We'll camp where we can - on the side of the road, on a park bench, anywhere,'' Fryatt said.

They'll also contend with 40 plus degree heat and 40km headwinds as they cross the Nullabour. 

However, the route takes the riders through Adelaide, Melbourne and Canberra en-route to Sydney, where cyclists will battle traffic. They also have to go over the Australian Alps twice.

As a cyclist Cross is a sprinter so he has been training for longer journeys. 

He spent five days at Christmas riding to Bendigo, where he also had to contend with 40 plus degree temperatures. Completing that trip firmed his resolve to take part in the Indian-Pacific.

"But this is going to take me right out of my comfort zone,'' he added in something of an understatement.

He said being able to back up day after day after riding long distances will be tough. Decision making will also be crucial.

"Say I ride 140km and get to a service station at 11am and the next one's 180km away. The thing is do stay there and maybe waste a day, or risk heading off,'' Cross explained.

Fryatt began training in earnest six months ago and is clocking up 500 to 800kms a week. This includes a number of rides between 200 and 300kms. He thinks he's about as well prepared as he can be.

"It's all a bit of an unknown though,'' he added.

Once riders arrive at the finish at Opera House they generally then head to Bondi.

"We tip our back tyre in the Indian Ocean in Western Australia and the front tyre in the Pacific in Sydney,'' Fryatt explained.

But there'll be no fanfare when they finish.

"There'll be no-one there, we'll reach the Opera House steps, and that's it,'' Fryatt said.

Cross has spoken to Buddy's mum and sister-in-law. He'll phone him before leaving for Western Australia and plans to meet him when he arrives in Sydney.

So far he has about $400 pledged.

Cross said his wife, Tanya and daughter, Alex are 'quietly supportive.'

"But my son Ben thinks I'm bonkers,'' he added.

Both Cross and Fryatt understand it's going to be an ordeal and an arduous way to see a bit of Australia.

Any worries?

"I'm shit scared,'' Cross replied.

"Yeah, me too,'' Fryatt agreed.