Is this a good place to bike?

Lower part about..75 milex

Not sure if it is a multi-use trail.... but, the lower trailhead is pretty wide. It is a steep incline though. The trail starts to get less steep the higher you go but also more narrow. An intermediate rider could get a decent ride out of it for sure. It is a short trail. Glendora Fire Road trail like right by it, which is very popular with Mountain biker riders. If I was conditioned to ride, I would start on the Fire road trail, go up Glendora Mountain road about 4 blocks, then you'll see the Colby trail entrance on your left. Then you can just go down it from there. It would be a pretty wild ride in some parts. Have fun!