Hurrey’s Performance – Hamilton NJ’s Premier Auto Repair, Offroad, Diesel & Performance Shop

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HURREY’S PERFORMANCE • FITMENT TOOL

Hurrey’s Tire, Offset & Gear Ratio Calculator

Compare tire sizes, see diameter and revs per mile, visualize offset and backspacing like an engineering diagram, and estimate gear ratios for bigger tires – before you order anything.

Real-world style guide – not guaranteed fitment Always verify clearance lock-to-lock & at full compression Speedo & ABS recalibration recommended on bigger changes
HURREY’S

Privacy: Hurrey’s Performance does NOT store, transmit, or receive anything typed into this tool. Data only reaches us if you manually email, text, or otherwise send your summary or information.

Vehicle Identification (Optional)

Add your VIN or license plate for your own records. Use the vehicle selector to auto-fill bolt pattern, center bore, and lug thread. All values are editable for manual override.

These fields are for YOUR reference only. They will appear on your printable summary if filled in. No data is ever sent anywhere from this page.

Tire Size & Revs Per Mile

Metric + SAE tire formats
Diameter, revs per mile & speedo impact

Current Tire

Mode:

New Tire

Mode:

Current
New
Tire Section Width Comparison
Current
New
Sidewall Height Comparison
Current
New

Tire Comparison Results

Enter tire data and click “Calculate Tire Difference”.

Speedometer @ indicated 60 mph
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Note: Use the gear ratio calculator below to see what gears make sense with your new tire size.

Wheel Offset, Backspacing & Poke Visualizer

Enter your current and new wheel specs to see how far the wheel moves toward the curb (poke) and toward the suspension (inner clearance), along with backspacing (mounting pad → inner lip). You can also add a spacer and note your lift height for context.
Current Wheel
Centerline
Hub
Curb side
Inner
New Wheel
Centerline
Hub
Curb side
Inner
Offset ⇄ Backspacing Converter
Uses nominal wheel width + ~1" lip allowance (common spec). Always verify with manufacturer drawings for tight builds.
Positive Offset
Mounting pad toward curb side pulls wheel inward (more backspacing).
Zero Offset
Mounting pad sits on the centerline of the wheel.
Negative Offset
Mounting pad toward inner side pushes wheel outward (less backspacing).
Want Hurrey’s to sanity-check your fitment?
Text clear side & front ¾ photos, wheel/tire specs, and a screenshot of this page to 609-782-8538, or call 609-249-4921.
📞 Call Hurrey’s Performance 💬 Text Fitment Info

Differential Gear Ratio & RPM Calculator

Use this to estimate what gear ratio you’d need to keep similar RPM when changing tire size. This is a guideline – real-world driving, engine torque curve, and transmission tuning all matter.

Enter your current ratio and tire diameters, then click “Calculate new ratio”.
Hurrey’s Performance – Fitment Summary
109 Flock Road • Hamilton, NJ 08619
Shop: 609-249-4921 • Text: 609-782-8538
HurreysOffRoad.com
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Enter tire, wheel, and gear values above and click the calculate buttons to generate a printable summary sheet.
IMPORTANT DISCLAIMER: This tool is an estimate only and does not guarantee fitment or safety. Always verify clearance lock-to-lock and at full suspension compression, verify torque by hand with a torque wrench, follow manufacturer and OEM instructions, and comply with all local/state/federal regulations. Hurrey’s Performance is not responsible for damage, improper installation, or use outside manufacturer/OEM recommendations.
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