This is a tough hike.
From http://www.wta.org/go-hiking/hikes/wagonwheel-lake :
It's one of the steepest trails in Olympic National Park, a trailhead sign warns (or boasts). Over 3000 vertical feet are gained in less than 3 miles. With tight switchbacks to no switchbacks, the grade is brutal. Then once you stop climbing, you get to traverse a brushy avalanche chute. When you arrive at Wagonwheel Lake, you realize it's no chrome hubcap-just a tiny forest-ringed pond with nary a good place to soak your feet. But if you can muster some energy to climb the open ridge behind it, this hike goes to four stars, and all that sweat and pain will be worth it.