Speed was not a factor in either of the fatal motorcycle crashes near Haast this week, police say.
On Wednesday, 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 State Highway 6 about 18km east of Haast.
The man, whose name has not been released yet, was travelling with a group from the North Island on a Fire Service charity ride, when the accident occurred about 12.30pm.
It is believed the crash resulted from structural failure in the vehicle.
Serious crash analyst Senior Constable Simon Burbery said he was confident the rider was not travelling at excessive speed when the crash happened and the trike had been taken for further examination to establish how the failure occurred.
A crash on Monday further north on SH6 which claimed the life of Christchurch man Steven Nottingham (59) also occurred at low speed.
Mr Nottingham was riding a Harley-Davidson motorcycle, which was towing a large trailer, 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.
Sen Const Burbery said the camper van was well within its own lane when the collision happened and the ongoing investigation was focused 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.
There had been hundreds of motorcyclists on SH6 every day this week heading to the motorcycle festival and the vast majority had been riding safely, Sen Const Burbery said.
''Both of these crashes involved an unusual combination of factors, and for once I can say that speed was not one of those factors.''
Otago rural road policing manager Senior Sergeant Aaron Nicholson, of Wanaka, who attended Wednesday's fatal crash, said driving conditions between the West Coast and Otago's rural areas were challenging enough for motorists.
However, travelling on a motorcycle posed an even greater risk ''given the lack of significant rider protection, uneven road surfaces, weather conditions that change quickly.
"This is on top of issues with some foreign drivers who can sometimes spend more time admiring the view than the road.''
''It's imperative that motorcyclists, along with all other road users, exercise enough patience, caution and manage their speed accordingly to get to their destination safely.''
