"I went off the handle bars at 35km/h and flicked into the middle of the road," he said.
"I was probably lucky I didn't get run over by oncoming traffic."
He was taken by ambulance to hospital and told not to cycle for three days but still got up the next day and carried on.
"From my knee to my groin was black. Every pedal stroke for the next three days my leg was hitting the bar and it wasn't nice.
"Even I thought I may have to stop but I kept it going and I sort of got away with it.
"All cyclists fall off their bikes. To a cyclist it's just, 'Bugger it I fell off'," Mr Calder said.
He said the hardest thing was cycling against headwinds and rain during the first three days.
"We were getting in after dark and we were just so knackered. We couldn't even go and get anything to eat.
"About 13-and-a-half hours cycling into a headwind and rain wasn't nice," he said.
Mr Calder made it to Cape Reinga and caught a flight back to Masterton.
The two men completed a similar ride going from Cape Reinga down to Bluff, in 2010, raising $14,000 for CanTeen.
"It was a challenge getting from down the bottom to up the top.
"It's far easier going from the top to the bottom.
"Not many people have done it both ways."
The pair rode between 150 and 200km a day and paid for all their own expenses.
Mr Calder said they decided to do the ride "just for a bit of personal satisfaction and we wanted to do something out there and raise money for CanTeen".
He said Mr Gane wanted to do the ride from top to bottom again in three years.
"Terry wants to do it again so we'll see what happens.
"We're a bit of a team. We stick together."
