245/45R18 VS 255/40R19
Comprehensive geometric comparison, rolling circumference difference, speedometer error, and proportional 2D CAD overlay.
Tire 1 (Base Spec)
Tire 2 (Comparison Spec)
Quick Telemetry Summary
Detailed Dimension Comparison
| Measurement | Tire A (Stock) | Tire B (New) | Difference | Variance % |
|---|
Real-Time Visual Tire Comparison
Speedometer Accuracy Impact
Changing overall tire diameter alters distance traveled per wheel revolution, causing the vehicle speedometer to read differently from your true road speed.
| Indicated Speed | Actual Real Speed | Speed Delta |
|---|
Custom Speed Calibrator
Enter any cruising speed to compute the exact speed discrepancy:
Note: Calculations reflect nominal mathematical geometry. Actual road speed is also influenced by tire wear, rim width flex, pneumatic inflation pressure, and OEM speedometer factory calibration offsets.
Ride Height & Ground Clearance
The effective axle centerline moves up or down by exactly half of the total overall diameter variance (Δ Diameter / 2), shifting vehicle clearance and center of gravity.
Mathematically Compatible Alternative Sizes
These sizes maintain safe overall rolling diameter compatibility with your base tire while varying width and aspect ratio for alternate wheel configurations.
| Alternative Size | Width | Overall Ø | Diameter Delta | Match Level |
|---|
* Always verify fender clearance, wheel offset, and load index with your tire installer before mounting non-standard alternative sizes.
Plus Sizing Guide (+1" / +2" Wheels)
Increase wheel diameter for enhanced cornering response and sporty appearance while maintaining your vehicle's factory rolling diameter with lower-profile sidewalls.
| Candidate Size | Diameter | Variance |
|---|
| Candidate Size | Diameter | Variance |
|---|
Minus Sizing Guide (-1" / -2" Winter Setups)
Downsize rim diameter while using taller-profile tires to absorb potholes, improve ride comfort, and reduce winter tire costs without changing rolling circumference.
| Candidate Size | Diameter | Variance |
|---|
| Candidate Size | Diameter | Variance |
|---|
Specialized Tire & Wheel Tools
Tire Size Calculator
Calculate comprehensive measurements and rolling specs for any individual tire.
Tire Size Comparison
Side-by-side dimensional comparison between two tire setups with visual delta.
Tire Diameter Calculator
Find overall diameter and ground clearance differences between profiles.
Tire Circumference Calculator
Calculate rolling distance and revolutions per mile/km for odometer checks.
Speedometer Calculator
Calculate speed reading variances caused by tire diameter changes across speeds.
Tire Size Chart
Explore 70+ common automotive tire sizes, specs, and standard applications.
Automotive Fitment & Safety Advisory
Calculations presented on TireSizeChecker.com are nominal mathematical projections. Actual installed rolling dimensions fluctuate depending on rim width matching, tire manufacturing tolerances (TRA/ETRTO standards), pneumatic inflation pressure, dynamic speed expansion, and vehicle cornering loads.
Always verify mechanical suspension clearance, brake caliper clearance, wheel fender lip clearance, speedometer recalibration, and load/speed ratings with a certified tire technician before mounting non-OEM tire sizes.