Stage 4 from Minehead to Teignmouth could see a change in the general classification as the riders encounter the hills of Somerset and Devon.
The stage starts with the climb of Lype Hill in Exmoor, with its summit at 12.5km. The riders drop down to the coast with the day's first intermediate sprint at Blue Anchor, before the road turns upwards again for the climb of Ralegh's Cross. That's two category 1 climbs in the first 50km.
It doesn't get much easier after that, with a very lumpy journey via the Blackdown Hills to the southern Devon coast. Two sprints at Honiton (104.7km) and Sidmouth (121.4km) are followed by the day's third and final category one climb of Peak Hill at 123km.
The final part of the stage is flattish but could be windy as the riders hug the coastline. There's one more small climb before the finish in Teignmouth, which could be the platform for a late breakaway.