The Protea Magistrate's Court sentenced musician Molemo "Jub Jub" Maarohanye and Themba Tshabalala to 20 years imprisonment each on Wednesday for murder.
"You did not premeditate the accident, it happened.... The court cannot impose the life sentence," magistrate Brian Nemavhidi said.
They were sentenced to four years for attempted murder.
For use of drugs, driving under the influence of drugs and racing on a public road, the pair were sentenced to a year for each count, to run concurrently.
They were drag-racing in Protea North on 8 March 2010, when they crashed into a group of schoolboys. Prince Mohube, Mlungisi Cwayi, Andile Mthombeni, and Phomello Masemola were killed. Frank Mlambo and Fumani Mushwana were left permanently brain damaged.
Family members of the schoolchildren sat emotional in the public gallery. One of the mothers was seen crying as she rocked herself back-and-forth.
Maarohanye and Tshabalala stood in the dock, heads bowed, listening to the sentencing.
They were found guilty on 16 October of four counts of murder and two of attempted murder, of using drugs, of racing on a public road, and of driving under the influence of drugs.