Some loose gravel led to a tyre touch with the rider in front before Andrew "flipped dramatically into the air and crashed hard onto the road".
His new helmet cracked and he took the impact on the left side his body.
"My helmet absolutely saved my life."
Various riders came to his aid and offered assistance.
Despite being worse for wear, and with only about 50km to go and the fact his bike hadn't suffered mechanically, he decided to soldier on.
"I rode with one hand and asked the others to keep going as I wanted them to do well.
"I struggled with one arm and a battered and bruised left side but made it to the next rest stop.
"There was no first aid at the rest stop but a rugby coach had some strapping tape so I asked him to strap my hand, which I couldn't close, in the hold position so I could hold the handle bars.
"Then with adrenalin pumping off I went and finished the ride in a pretty good time [6h 49m 43s]."
After finishing he went to hospital where a check showed no sign of broken bones.
"The doctor said being on the older side of 50 usually meant lots of broken bones with that type of crash, but amazingly I survived, finished the race and live to tell the tale."