Here is where I bought the last ones. I went with this company because they had everything. Only one shipping charge to pay.
KG Motorcycle Tires & Accessories
http://www.kgmotorcycletires.com/
M906602 Cheng Shin C906 110/90H16 $51.78 ea
M907501 Cheng Shin C907 130/90H15 $56.45 ea
Inner Tubes
TS155005506C Inner Tube 5.00/5.50-15 CEN TR6 ea $13.25
TS16400460 Inner Tube 4.00/4.60-16 TR6 $9.36 ea
Rim Strips $2.00 ea
I'm on my second rear tire. My wife has a matched set. My daughter has them and my son-in-law. We all like them.