Where would my tire purchases go for.my business?

It's a choice and personal preference. You could enter those under supplies or you can use the Miscellaneous Expense category based on your personal preference.  Inventory is not required under the Tax Cuts and Jobs Act (TCJA) for 2018-2025.

According to TCJA, businesses with gross receipts below  $27M (inflation-adjusted amount for 2022 is $27M, and the amount for 2023 is $29 Million) are considered eligible to use the cash method of accounting for their inventory.  

• TCJA Comparison for Businesses: The law expands the number of small business taxpayers eligible to use the cash method of accounting and exempts these small businesses from certain accounting rules for inventories, cost capitalization and long-term contracts. As a result, more small business taxpayers can change to cash method accounting starting after Dec. 31, 2017.