The boys, both 14, were taken to hospital after the incident in High Street near Fremantle Road just after 3.40pm yesterday (March 27).
High Street was closed for hours as police investigated.
In an update, the Metropolitan Police says both boys are in a non-life-threatening or life-changing condition.
A man was also arrested on suspicion of dangerous driving and is still in police custody with no charges made, a spokesperson said.
Anyone with information can call police on 101 or message @MetCC on X quoting CAD 4868/27MAR.
Alternatively, contact Crimestoppers anonymously on 0800 555 111.
