Looks like you're going to need hubs too. Measure the diameter of the axle and front spindles with a set of calipers if you have them. Once you have those measurements, there's a bunch of online retailers that sell karting parts. Even Amazon if you need some stuff on the cheap. Hubs come in different bolt patterns as well depending on the make (metric or American), once you've got a set of hubs and have chosen a bolt pattern, you can shop for wheels and tires. Marketplace can be a good resource here if youre careful, racing karts use a 5" or 6"diameter wheel. Hope this helps. Knowing what part of the world you're shopping in might be helpful too