Also check southwest wheel. You can get a 3500# axle with 10" drum electric brake with 6 lug 5.5. Also you can run lug centric wheels on your 4 runner just use acorn nuts not shank nuts. Your stock spare is lug centric and the stock shank nuts actually have an acorn beveled tip on them. Ask me how I know...... the only reason you would need adapters is if you wanted to run a hub centric wheel on your trailer axle, I.e. match the stock wheels. Its personal preference at that point but since the spare will work on either I plan to save the 100$ and plan to use 2 stock black steel wheels that way the spare works on either the trailer or truck and the stock lug nuts work for either.