To provide technology capable of certainly preventing the occurrence of rim slip after rim assembling while ensuring rim fitting property in tire rim assembling.

In the lubricant for the tire rim assembling used so as to be coated on a fitting part of the tire and the rim, friction coefficient W in the wet state is 0.5 or lower and friction coefficient D in the dry state exceeds 0.5. The friction coefficient D in the dry state is preferably 0.8 or higher. In the tire, the fitting part with the rim is coated with the lubricant for the tire rim assembling.