This set of two 76 mm x 30 mm caster wheels for the Razor Crazy Cart (V7+), Crazy Cart Shift (V1+), and Crazy Cart XL (V3+) is a bit wider (or thicker) than the Crazy Cart caster wheels made for the earlier versions. Especially noteworthy is the flatter, less oval tire design. This feature makes these wider caster wheels a lot less punishing to indoor carpeting, something every parent can appreciate.
Depending on the width of your caster forks, you may need to add an addition washer or two to your caster's axle as a spacer.
Model versions can be determined based on the product ID code on your Razor product. The product ID code can be found on the battery cover and/or on the bottom of the frame. The 7th and 8th numbers in your product ID code are the version number of your Razor product (e.g. "01" = Version 1, "02" = Version 2, etc.).