Front tire

I'm looking at a Pirelli xcmh front tire and a Dunlop 606 rear tire combo. However they only make the Pirelli front as a 80 100 21. Has anyone ran that size and or tire for that matter. Seem kinda skinny. Thoughts? Also I'm going to run a 130 90 18 in the back with the 606.

You didn't say what type of riding you will be doing with those tires. Since you are wanting the 606 for the rear, I assume some dual-sporting. I did the Oregon Backcountry Discovery Route with 606's front and rear, and thought they were great! Good on the dirt/gravel, and MUCH better than expected on the asphalt! Wear is good also.

Never have run the pirelli but am a strong advocate for the 606 front rear combo!  they handle the pavement just fine and do great on the fire roads and trails as well. 

I ended up going with the 606 rear and the Pirelli front. The Pirelli has great reviews for on and off road. And of the 606 rear is a beast. Can't wait to see how they perform. Now I just need to mount them. And go ride