Organisers of the Gran Fondo world championships said the closures would ensure the safety of about 1500 competitors and spectators.
“The course will be controlled by WA Police and traffic management,” the CIC Events Management website said.
“Recommended alternate routes will be identified and there are managed crossing points and designated routes for local residents in areas throughout the course.”
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READ NOWA flyer delivered to nearby residents warns of delays, lists road closures in the vicinity and recommends other routes.
MORE: Gran Fondo commits to route changes
Signposts at the side of roads affected by the cycle race appeared several weeks ago.
The race route changed after the event trials in March caused traffic chaos and left some residents unable to leave their properties.
Spectators are encouraged to watch the event and support local riders competing against national and international cyclists.
The race will start with a time trial at Rottnest Island on Thursday before a mainland team relay on Friday and the Sunday final uphill leg to Kalamunda.
Women and men aged 55 years and over will compete over 105.8km, with men under-55 to pedal 154.5km and finish in the same location.
Councils supporting the race will hold community events, including several at Mundaring Community Sculpture Park and Morgan John Morgan Reserve in Glen Forrest.
For details, visit granfondoworldchampsperth.com.au.