The DRW Toolbox
Free wheel and tire tools built for drag racers and performance enthusiasts. Calculate fitment, convert backspace to offset, and find your vehicle's perfect wheel setup right here, right now.
Compare your current wheel and tire setup against any new combination. See poke, inset, overall diameter, sidewall height, circumference, ride height change, revolutions per mile, and speedometer error, all calculated live as you type.
Convert between wheel backspace (inches) and ET offset (mm) instantly. Enter your wheel width and either value, the other is calculated automatically. Includes a live cross-section diagram showing exactly where the hub face sits relative to the wheel centerline.
The fitment guides provided apply to vehicles with O.E. suspension, wheel wells, and brakes unless otherwise noted. Ensure to ALWAYS test fit the wheel first. Once a wheel has been mounted to a tire, it cannot be returned.
Testing and fitting wheels on a drag racing car is one of the most important steps before heading to the track. Getting the fitment right the first time saves you money, prevents clearance issues, and keeps you racing instead of troubleshooting. Whether you're swapping to a new set of WELD Racing, Race Star, Forgestar, or Billet Specialties wheels, these steps apply to every build, from street/strip muscle cars to dedicated Pro Mod race cars.
Before you start, confirm your wheel's bolt pattern, offset, and center bore match your vehicle. Use the Backspace & Offset Calculator above to convert between backspace and ET offset if you only have one measurement. If you're unsure about clearance for your specific combination, call our fitment team at 1-(833)-287-6088 before mounting anything to a tire, once mounted, wheels cannot be returned.
Place the car on a flat, stable surface and engage the parking brake before beginning any work. Safety is always the top priority.
Use a jack to raise the car high enough to work comfortably underneath. Secure it on jack stands and confirm the car is stable before proceeding.
Use a lug wrench to remove the lug nuts or bolts securing the current wheels. Set the wheels aside safely.
Clean the new wheels and inspect them for any defects or damage. Ensure they are free from debris before mounting.
Verify the bolt pattern, offset, and center bore size match your vehicle. Consult your car's manual or a fitment specialist if unsure.
Place the new wheel onto the hub and confirm it sits flush without wobbling. Use wheel spacers or hub-centric rings if needed to correct the fit.
Measure the gap between the wheel and suspension components, brakes, and fenders. There must be sufficient clearance to avoid interference at full compression and steering lock.
Inspect wheel alignment to ensure correct positioning. Misaligned wheels affect handling and performance. Use alignment tools if necessary.
Remove the test wheel, apply anti-seize lubricant to the hub if needed, then reinstall and hand-tighten lug nuts in a crisscross pattern to ensure even pressure.
Use a torque wrench to tighten lug nuts to the manufacturer's recommended specification. This is critical for safety and preventing wheel-related failures.
Repeat steps 6 through 10 for every wheel on the car to ensure consistent fitment and torque across the axles.
Carefully lower the car from the jack stands. Once on the ground, re-check all lug nuts to confirm they remain properly torqued after the vehicle's weight is applied.
After fitting new wheels especially with a different offset, we recommend having the alignment checked. Offset changes can shift your suspension geometry and affect tire wear and handling.
Take the car for a test drive to confirm the wheels are properly fitted. Listen and feel for any unusual vibrations, pulling, or handling issues before hitting the track.
