Mary Connors, 10, from Carberry in Co Kildare, remained in a coma for more than a week after the tragic accident on the outskirts of Cork city on Sunday, September 2, last.
She died at Cork University Hospital (CUH) on September 13.
Cork Coroner’s Court was told she had not been wearing a helmet at the time of the accident.
Mary had been staying with relatives at Kilbarry Cottages on the Old Mallow Road, Cork, for several days.
She left the house at about 2pm on Sunday afternoon to go for a ride on the bike.
The 18-speed mountain bike, designed for boys, had been bought just a month earlier.
Tony Ahern told coroner Dr Myra Cullinane that he was sitting in his car at traffic lights at the junction of the Old Whitechurch Road, Old Mallow Road and Red Forge Road near Blackpool when he saw the bike speed across the road in front of him, and slam into a stone wall near Garvey’s Bridge.
He said he did not see Mary make any attempt to brake.
Martin Dunne, who was also parked at the junction, said he saw the little girl come down the hill, wrestling with the bike’s handle bars as if she was trying to turn right.
“The bars were shaking in her hands,” he said. “I thought she was frightened as opposed to the handle bars not working.”
The bike had come down the Old Mallow Road hill, sped across the junction, hit a curb, flinging Mary over the handle bars headfirst into a stone wall.
The accident site was about 270 metres downhill from her relatives’ house.
She was taken to CUH but never regained consciousness. She died 11 days later of multiple skull fractures and severe brain trauma.
A forensic examination showed the bike, its tires and brakes were in perfect working order before the accident.
Forensic collision investigator, Garda Mark O’Connor, said there was no evidence she used her brakes before impact.
And he said if Mary had freewheeled from the house, she could theoretically have been travelling at up to 77 kilometres (about 50mph) at the time of impact.
The jury of two men and four women returned a verdict of accidental death.
Mary’s father, Edward, was in court with four relatives for the inquest but declined to comment afterwards.