Product Summary

Universal Fit, Steel, Bare

  • Accurate way to measure and confirm backspacing and offset using the actual tires you plan to use
  • Measures 5 lug applications 14-20" wheel diameter and 7-17" wide with bolt patterns of 5x4.5, 5x4.75, 5x5, and 5x5.5
  • Assembles inside your tire to verify fitment against frame, suspension, and body
  • Laser cut and press bent from 10 gauge steel for strength
  • Tool free design uses 1/4-20 carriage bolts and wing nuts to adjust and secure tool

Key Specs

BrandSpeedway Motors

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  • Easily determine proper wheel fitment backspacing specs for custom applications
  • Mounts inside tire so that actual tire size desired can be test fitted to vehicle
  • Allows user to confirm wheel and tire clearance to body, frame, and suspension
  • Laser cut and press bent from 10 gauge steel in house at Speedway Motors
  • Laser etched designations, including wheel bolt pattern, wheel diameter, and more
  • Provides direct measurement of wheel back spacing to order new or custom wheels
  • Wheel fitment tool supports 14 to 20 inch wheel diameters and 7 to 17 inch wheel widths
  • 5-lug wheel bolt pattern fitments include 5x4.5, 5x4.75, 5x5, and 5x5.5
  • 1/4-20 carriage bolts and wing nut hardware provide quick, tool free adjustments

No Longer Second Guess Wheel Measurements for Your Custom Build Needs

Much like wiring, measuring for proper wheel and tire fitment is considered a stressful adventure in the automotive hobby. It’s nothing for most enthusiasts to bolt on some performance go-fast bits, or even weld up an exhaust system, but when it comes to figuring out what wheel dimensions will work (or that aforementioned wiring) all bets are off and the second guessing starts in earnest.

Sure, some will throw a spare wheel that is lying around the shop on the car and check fitment, or even borrow a wheel from a friend. Still others will ask total strangers on social media what “should” fit and hope they’re correct. Why not take the stress and inaccurate guesswork out of your wheel and tire fitment with our new Wheelfit wheel fitment tool on your next project?

Accurate Wheel Measurements in Minutes with The Tire Sizes You Plan to Use

Confirming your wheel specs, including backspacing and offset, to order new or custom wheels can be accomplished in no time with our wheel backspacing tool. Simply assemble the wheel fitment calculator tool extensions inside the tire you plan to run and secure the sidewall clamps. Bolt the hub mounting plate to the extensions and you’re ready to mount your tire and take some measurements with our wheel offset measuring tool! It’s that easy!

Our wheel fitment tool is made from 10 gauge steel and laser etched with pertinent measurement points. The wheel offset tool is much sturdier than plastic models that have been on the market (that don’t use an actual tire) and is a much better value than the cast aluminum models as well with precise wheel bolt pattern mounting options in all major five-lug bolt patterns using 1/2-inch studs, plus 5x4.75 with 7/16-inch studs. These specific wheel bolt patterns and stud hole sizes create a much more accurate mounting versus universal slots that inject slop into your fitment check.

Everything you need is included in the wheel fitment tool kit to measure for 14 to 20 inch wheel diameters from 7 to 17 inches wide! Just supply the front and rear tire sizes you will be using, assemble and mount the tool with tire secured to your axle flange or front hub. Once secured with at least two wheel lug nuts you can check for frame and suspension clearance by cycling your suspension up and down with a floor jack (unbolting or removing your shocks/coilovers may make this easier). Turning your front wheels from lock-to-lock will confirm steering angle changes will not create tire to frame/sheetmetal interference as well. Easily loosen the wing nuts and adjust the tool’s backspacing for optimal tire clearance and then lock the adjustment down. Remove the wheel backspacing tool and measure your final backspacing needs to order your new or custom wheels.


Wheel offset and backspace are two of the most misunderstood wheel terms, but they are at the center (no pun intended) of your wheel measurement needs to ensure your custom wheels fit your application. Our new wheel fitment simulator tool helps immensely, but you still must do some basic math. The tool verifies a specific tire size and placement, and then you take some final measurements from this tool and input them into some basic math formulas (see our Installation Tips section).

First, let’s provide a few quick definitions here to help you:

Overall Wheel Width: This is the total width outside of the wheel lip flange, usually 1-inch wider than the inside “stated width” wheel lip measurement the tire seats. This is measured without a tire mounted using a ruler or measuring tape across the wheel and is expressed in inches.

Wheel Centerline: This is the overall wheel width measurement divided by 2 to halve the dimension, giving us the true centerline dimension of the wheel, expressed in inches.

Backspace: This is simply the distance from the wheel mounting face (where it sits on your brake rotor or drum) to the rear outside wheel lip flange. This is measured using a straight edge across the back of the wheel (without a tire mounted helps) and a ruler or measuring tape from the mounting face to the straight edge and is also expressed in inches.

Offset: This is the measurement between the wheel mounting face and the centerline of the wheel’s width. This one is a little harder to measure, especially on wheels that are solid or have small window openings between the spokes, and confusing enough to some it is expressed in millimeters that can be either a positive or negative dimension.


BrandSpeedway Motors
NotesSupports all common 5-lug wheel bolt patterns, does not support 4-lug or 6/8-lug vehicles
Material TypeSteel
Sold in QuantityEach