The investigation into yesterday's fatal crash about 18km East of Haast on SH6 appears to have resulted from structural failure in the machine.
A 70 year old man riding a home built, VW powered, trike was killed instantly when he crashed into a bank on a straight stretch of highway.
Serious Crash Analyst Senior Constable Simon Burbery said he was confident the rider was not travelling at excessive speed when the crash happened. He said the trike had been taken for further examination to establish exactly how the failure occurred.
The man, whose name has not yet been released, was travelling with a group from the North Island on a Fire Service organised charity ride.
Meanwhile the investigation into a crash on Monday further north on SH6 which claimed the life of Christchurch man Steven Nottingham also occurred at low speed.
Mr Nottingham was riding a Harley Davidson motorcycle and towing a large trailer behind when he crossed the centre line on a tight left hand bend and crashed into the side of a camper van travelling in the opposite direction.
Senior Constable Burbery said the camper van was well within its own lane when the collision happened. He said the ongoing investigation was focussing on the involvement of the trailer in relation to the rider's loss of control.
Both deceased riders were on their way to the Burt Munro Challenge in Southland.
Senior Constable Burbery said he had seen hundreds of motorcyclists on SH6 every day this week heading to Southland for the rally and the vast majority had been riding safely.
"Both of these crashes involved an unusual combination of factors, and for once I can say that speed was not one of those factors," he said.
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