O.k. guys. I changed my mind about tires. I was dead set on gettin' a set of MT-21's. But I changed my mind. The rear TW "slick" had to go. After many inquiries to the local dealers & psycho shops, I found a pretty good deal on the Dunlop 606. Most everything I read and just about everyone I talked with said the 606 was "the" tire. Long story still long, I've got a new 120/90-18 Dunlop 606 rear tire now. Here's what's puzzling me. The damn thing barely had any air pressure in it from the shop and it's feels like its overinflated! I'm using a standard tube and I even put "more" air in it to raise the pressure 17 psi. What kind of sidewall construction does this tire have? It's hard as a rock with virtually no air in it! How much pressure should I be running in this piece of rubber? It feels like 17 psi is way too much. Thanks in advance.