More than 8000 bike enthusiasts will flood Glasgow Green for the start of the freshnlo Pedal for Scotland from Glasgow to Edinburgh.
Most of the riders will be completing the 47-mile Challenge Ride following a mixture of closed roads, quiet back roads and cycle paths that cuts through Scotland's two largest cities and the countryside in between.
Around 800 cyclists will also set off to complete the 110-mile Sportive Ride between the two cities.
This route takes riders out of Glasgow and into the Southern Uplands where they will complete the equivalent of riding up the Tour de France's notorious Alpe D'Huez, twice.
The 47-mile route is designed for both regular cyclists and those who haven't been on a bike in a while.
There are rest stops every 10 miles serving free refreshments, plus home baking for sale at Avon bridge and a free lunch at Linlithgow Palace.
Joining riders on the day will be celebrity ambassadors including round-the-world explorer Mark Beaumont, and when the cyclists arrive at the finish line at Edinburgh's Murrayfield Stadium, there will be entertainment and activities.
Last weekend, more than 3400 riders took part in the Glasgow Family Ride which started and finished at the Sir Chris Hoy Velodrome.
Ian Aitken, chief executive of Cycling Scotland which organises Pedal for Scotland, said: "It's amazing to have so many cyclists taking part across the freshnlo Pedal for Scotland rides this year.
"We had a fantastic start with our Glasgow Family Ride last week, and this weekend we're set to have more than 8000 taking part, with the majority cycling from Glasgow to Edinburgh.
"It's a testament to cycling's growing popularity."