As the name suggests, they are designed for models with aluminum wheels. However, with some modifications, like me, they can be mounted on steel rims. I put them on my son's Tao Tao 125G Cheetah. YOU NEED FASHION. I give 5 stars for quality and value. I knew in advance that I had to change them. First, the center annular recess on the back of the spacers is too small and does not sit flush with the hubs. Luckily we have a lathe at our shop and I was able to cut a larger relief ring for a proper fit. About 0.088 inches more if I remember correctly. The second change concerns the hubs. With a steel rim, they are screwed to the hubs at the front. You will need to convert the hubs to a studded hub and then use the included flare nuts to attach the spacer to the hubs. The problem with this is that the hubs are M10x1.5 threads and the lug nuts are M10x1.25. This requires retapping the hubs to change the thread pitch. This creates a weak thread, but you only do this to put new bolts in the back that will be used as studs. The tapered nuts hold everything together anyway, so the strength of the socket threads is ultimately irrelevant. I used 8.8 M10x1.25x40mm flange bolts. I thought about using 10.9 but for a kids quad 8.8 should be more than enough. The last step was to get some 10mm washers and M10x1.25 nylon locknuts to hold the rims in place. It was a lot of work but the end result is perfect. The rear tires are now the same width as the front tires. I bought a $120 "steel rims" kit off eBay from a popular ATV store and they sent something like this. So they came back, and here we are. Fantastic value for money if you have aluminum wheels or can convert to steel rims.