Compare Wheel & Tire Setup
Enter your current setup and your proposed setup to estimate inner clearance, outer poke, track-width change, and tire diameter/speedometer impact.
What this rim fitment calculator tells you
Wheel fitment is mostly about geometry. A wheel can look close on paper, but a few millimeters in the wrong direction can create rubbing on suspension parts or fenders. This calculator helps you compare two setups quickly so you can see where the wheel moves inboard and outboard.
It also includes tire diameter comparison, which matters for speedometer accuracy, gearing feel, and ground clearance. If your new tire diameter is too far from stock, your speed reading may be off and ABS/traction behavior can change on some vehicles.
How to read the results
1) Inner clearance change
This value estimates how the inner wheel lip moves relative to the hub. If the number says less inner clearance, the wheel is moving closer to your strut or control arms, which can be a risk point.
2) Outer poke change
This tells you how much farther the outer lip sticks out toward the fender. More poke can look great, but too much often causes fender rubbing over bumps, during turns, or with passengers and cargo.
3) Track width change
Track width is the distance between the wheel centers on the same axle. Lower positive offset generally increases track width; higher positive offset decreases it.
4) Tire diameter and speedometer effect
If your new tire has a larger diameter, your actual speed will be slightly higher than indicated. If it has a smaller diameter, your actual speed will be lower than indicated.
Quick fitment rules of thumb
- Try to keep tire diameter within roughly ±3% of your baseline setup.
- Be cautious when reducing inner clearance by more than 3-5 mm unless you have measured space physically.
- Outer poke increases over 10-15 mm often require fender rolling, camber adjustment, or narrower tire choices.
- Real-world fitment depends on tire brand shape, alignment, ride height, and suspension travel.
Important fitment factors beyond width and offset
Brake caliper clearance
Two wheels with the same width and offset can still differ in spoke profile. Always verify caliper clearance with templates or manufacturer data.
Center bore and hub rings
Your wheel center bore should match or exceed your hub diameter. If larger, quality hub-centric rings help maintain proper centering and reduce vibration risk.
Bolt pattern and seat type
Confirm bolt pattern (for example, 5x114.3), lug seat type (conical, ball, or flat), and proper hardware length for safe installation.
Suspension and ride height
Lowered vehicles have less bump travel and often require tighter fitment tolerances. A setup that clears at static ride height may still rub under compression.
Final note
This calculator provides a strong first-pass estimate, not a substitute for direct measurement. Before buying wheels, verify clearances with a test fit whenever possible. A small investment in measurement saves a lot of time and money later.