Get the right gap everytime without damaging your wheels!
Pinewood Derby Car Gap Gauge Perfect Gap™ Wheel Tool
1.397 mm Precision wheel gap gauge. Gives you more than a credit card, but less than 2 credit card widths. We believe this is the best possible gap for wheels. Does not mar or damage your wheels or body of your car unlike the metal counterpart. Will work with most car designs.
Super simple. Super affordable! Have it in less than a week!
Hammer axle down until shim is snug,, then remove shim. You have a 1.397 mm gap for super fast speed.