Start at Monrovia Canyon to White Saddle to Newcomb's Pass and down to Sturtevant to Chantry Flants, then ride the road back to Monrovia. I forgot to turn on my GPS for the first few minutes (the steepest part of the ride!). Enjoy.
Climbing is all fireroad- amazing views of LA, the ocean, Baldy and beyond. The singletrack descent is exposure, switchbacks and slippery at times. Technical rocks and fun through to Chantry. Bring way more water than you think you need, and plenty of food. This ride can end up being very long.