Amazing hike if you like the challenge of hills! This was one of the only hikes that got me sweating so much! And my dog enjoyed it as well. Go early as to avoid the sun, there's no shaded areas. Easy to get to, plenty of parking. Once you go around the loop make a left to the steep incline and it keeps climbing from there. I only got to 2 miles up before I decided it's time to come back down, but the view was beautiful!
Since the housing development surrounding Skyline has occurred I see most if not all mountain bikers using this area as a workout rather than mountain biking down trails. After 20-30 minutes of riding up the fire road (depending on your pace) you'll start to see single track off the right hand side of the road. These trails offer some steep technical sections and other than the lack of trail maintenance offer some of the best single track around. It's a shame this map doesn't even point this out. There's two single track trails from the mid way point up the fire road and two to three if you ride all the way to the top. If you go down any of these single track trails you're now on advanced trails and should be wearing pads.
Lorena d. on Skyline Drive
This's is a good trail to get a workout. Going up the initial hill will definitely get you to burn calories because it is very steep. Gravel is loose and slippery.
as far as mountain biking goes great work out but I look for great downhill rides and this was an ok 1. the ride up out weighs the downhill due to the fact your going to ride an hour back up for what took me and my buddies under 5 minutes to get down. it has its moments and riding through the 90's smog isn't too appealing