📏 Plus-Sizing Calculator

Going up in wheel size? Enter your stock setup and target wheel diameter. We'll recommend tire sizes that keep your speedometer accurate and your ride comfortable.

🔵 Stock Setup

Stock Wheel (inches)

Stock Tire Size

Enter tire size to see stock specs.

🟠 Target Setup

New Wheel (inches)

Preferred Width (mm) — optional

Tip: Each +1 inch in wheel size typically requires a -5 point drop in aspect ratio to maintain diameter.

🔧 How It Works

Plus-sizing means installing a larger wheel while maintaining the same overall tire diameter to keep your speedometer accurate. The rule of thumb: for every +1 inch in wheel diameter, drop the aspect ratio by approximately 5 points. This calculator generates candidate tire sizes around your target wheel diameter and filters out any combination that exceeds a 3% diameter difference from stock.

How to use: Enter your stock wheel size and tire size (e.g., 215/55R17). Enter your new wheel diameter and optional preferred width. Click Find to see recommended sizes ranked by diameter accuracy. The sidewall chart shows how much ride comfort you may lose.

Tip: A sidewall drop of more than 0.5" will noticeably stiffen the ride. If you daily-drive on rough roads, consider staying at plus-one instead of plus-two. Always verify clearance with a test fit before buying.