The riders' ability to recover from the previous day's effort will be tested very early on in the fourth day as the route heads out of San Jose straight up the steep and twisty Sierra Grade climb not even 10km from the start line.
Once over the summit of this beastly hill, riders will have a long, gradual descent before turning onto Calaveras Road where they'll have a short "wall" of a climb to get the legs warm again.
The riders should be pushed along by a tailwind to Livermore where they will turn south down the scenic Mines Road and bypass the route to Mount Hamilton, instead turning onto Del Puerto Canyon Road for the final climb of the day.
It's a long, gradual descent through the canyon down to Patterson and then a pancake flat run up to Modesto. While the terrain at the end may not be terribly difficult, strong crosswinds could make it difficult for the groups which have split up on the climbs to come back together.
In all likelihood, it will be a day for the sprinters, especially if they've been denied on the previous two stages.