--- Yes, the "hook bead" or "hook edge" rims have the lip on the inside. Actually, I rode on those tires for a couple months at 115 psi before the blow-off. Those straight-sided rims were made back when typical road tire pressures were only ~ 75 psi.
Originally Posted by saturnsc2
After I learned the HARD way about rims, I finally consulted the guru, Sheldon Brown's glossary at:
Thus spake Sheldon:
"Hook Edge Rims
A rim with a ridge on the inner edge to help retain the bead of a clincher tire. Some older rims were straight-sided, and will not hold a tire as securely as a hook-edge rim (that is, the tire cannot be inflated to as high a pressure.) Virtually all good quality rims in current production are of the hook-edge type."
Lucky for me, the blow-off did not occur on the road. It happened about 20 minutes after I had parked the bicycle in the church meeting hall. It suddenly went off with a loud BANG. We first thought it was the coffee pot blew up! Hahahaha