Declan Newsome, 15, would not have been able to stop in time to avoid the stationary silver Suzuki, Bradford Coroner’s Court was told.
Collision investigator Steve Green said Declan tried to cycle round it but lost control of his bike when he clipped the car with his handlebar.
The 15-year-old then hit another car, which was driving towards him along Hopton Lane, before coming off his bike.
He sustained a serious head injury and was airlifted to Leeds General Infirmary where he died three weeks later.
Castle Hall Academy pupil Declan, of Trinity Street, Mirfield, had been cycling downhill towards the town when he hit the Suzuki on July 9 last year.
The Suzuki driver, Donald MacMillan, said when he was at the bottom of the hill, he had pulled in behind a parked car to let vehicles coming the other way get past.
He said that Declan only looked up to see that he had stopped when he was six or seven feet away.
Mr Green, who examined Declan’s bike after the crash, said: “The braking system to the back was grossly maladjusted and what we would call totally ineffective.”
He said that even with the brakes properly adjusted, if Declan was going at 20 miles per hour, he would have needed 37 metres to stop.
“It was quite clear that the brakes, prior to this collision, had been ineffective,” he said.
“We will never know whether Declan had applied his brakes before he hit the car but if he had he would not have been able to stop.”
In a statement read by the coroner Roger Whittaker, Declan’s father Kenneth Newsome said his son took good care of his bike and checked it every Sunday.
Recording a verdict of accidental death, Mr Whittaker said: “From the examination of the bicycle after the incident, it is clear that whatever maintenance it received was ineffective as far as the brakes were concerned.”
He added: “By all accounts, particularly his dad’s, Declan was a lovely fellow. I can imagine that.
“It does not make the tragedy any better or worse, but a tragedy it is, particularly to the family.”
Declan’s parents Kenneth and Harriet were joined in court by Mirfield councillor Vivien Lees-Hamilton.
After Mr Whittaker recorded his verdict, Mr Newsome asked him to recommend that measures to stop speeding were put in place in Hopton.
Mr Whittaker said: “Sadly, in this case, there is nothing I can do in asking for the speed limit to be reduced as I do not think speed was related to Declan’s death.”