You can print replacement gates for Mario Kart Live: Home Circuit for free, or order them from Nintendo
I'm sure some of you have been wondering what happens if your Mario Kart Live: Home Circuit gates get mangled in a few crashes, or some other mishap. The good news is that getting a replacement is as easy as firing up your printer.
Nintendo has revealed that you can print your own replacement gates at home, if you'd like. You can also use the Nintendo online store to order replacements for gates and arrow signboards. As for other replacement parts, Nintendo doesn't specific how those can be obtained. In other words, if you wreck your kart and its in need of serious repair, you'll have to go through the traditional Nintendo customer service option.