The incident happened last Wednesday at 7.20pm on the A24.
Police say the cyclist was pushed by the riders of a dirt bike, which then passed him and made off towards the roundabout.
The driver has been described as a white man wearing a dark grey hoodie, navy trousers, and a balaclava.
The passenger has also been described as white and was wearing a dark jacket.
Inspector James Green, Borough Commander for Mole Valley, said, “This is a serious assault which has left a man with significant injuries. We’ve released this footage, which was captured at the time, to show the shocking nature of this unprovoked attack.
“Enquires to identify those involved are ongoing but if you were in or around the area between 7.15pm and 7.30pm on Wednesday, 29 May or have any information which may help then please contact us.
“Perhaps you recognise the bike itself and know who it belongs to or where it is now? Do you have CCTV, dash cam or helmet cam footage which could relate? If so, then please get in touch.”
