The 100 mile race which starts and ends in Birmingham takes in Herefordshire and Worcestershire via Sandwell, Dudley and Staffordshire.
15,000 cyclists are taking part. They have been setting off in stages from Broad Street.
Roads are closed along the route. Click here for a detailed map and list of road closures.
More than £1million is expected to be raised for Midlands-wide charities.