Anchor Road, Canons Road, Canons Way, Lower College Street, Bridge Valley Road, the Portway, some roads around the Cumberland Basin System and others will be closed early morning until mid-afternoon.
The race starts at 09:30 from Anchor Road, Harbourside.
More top news
Rugby fans are eagerly awaiting the start of the Rugby World Cup but it's not just sports enthusiasts who will benefit this autumn.
The last pilots to train on Lynx and Sea King helicopters in Somerset have taken part in a parade in front of some special guests.
Ahead of the Rugby World Cup we're looking at the sport in our communities and what impact this year's tournament could have on the game.