A Few Facts About Wheels
Before you buy wheels, accurate measurements and thorough clearance checks are non-negotiable. This guide explains the core specs, how to verify space around suspension and brakes, and how to use GAWR and load ratings so your setup drives safely and looks right the first time.
Measurements
Measure on the wheel and confirm on the vehicle. Each spec affects safety, handling, and stance. Offset relates directly to backspacing/front spacing; always include tire bulge when calculating spacing because the section width can extend past the wheel lip.
- Wheel Diameter – Dictates tire choices, brake clearance, and overall look.
- Wheel Width – Influences tire selection, sidewall shape, and inside/outside fender clearance.
- Backspacing – Distance from hub face to inboard rim lip; include tire bulge to avoid rubbing on frame/arms.
- Front Spacing – Distance from hub face to outboard rim lip; include tire bulge to keep fenders and liners safe.
- Bolt Pattern – Lug count and circle diameter; must match the vehicle hub or a proper adapter system.
- Center Bore Diameter – Controls hub-centric fit; use quality hub-centric rings if the wheel bore exceeds the hub.
Clearance Checks
Mount or mock-up one corner. Turn the steering lock-to-lock and simulate suspension compression. Verify clearance to brake components, lines, and brackets—don’t rely on diameter alone; spoke shape and offset affect caliper and rotor hat clearance.
- Outside fender/bumper lip
- Inside frame, braces, and brackets
- Suspension/steering components (tie rods, control arms, brake lines)
- Brake caliper and rotor hat clearance
Safety & Load Ratings
Use the GAWR of the heaviest axle and confirm each wheel on that axle has a load rating at least 50% of that GAWR to ensure safe operation under load.
Professional Fitment Advice
- Select offset/width for your use case (daily, towing, track, off-road).
- Account for tire section width; tires can extend past the wheel lip.
- Prefer hub-centric fit; use quality rings if center bore is larger than hub.
- Confirm spoke/caliper clearance, not just overall diameter.
- Plan for lifts/lowers/big-brake kits before finalizing specs.
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Reviewed by the Performance Plus Tire Fitment Team.
