What rims does the AT26A handle?

The maker rates it for 12 to 24-inch rims, which covers most passenger car, SUV and light-truck wheels. Very small trailer rims and heavy truck wheels are outside that range.

What does the assist tower do?

The assist arm pushes down on the sidewall while the bead is worked, keeping stiff or low-profile tires seated on the rim. It makes hard sidewalls easier to mount and demount than on a changer without one.

Does it need a big air compressor?

Yes. It runs on shop air, so you need a compressor with enough volume and pressure to drive the bead breaker and turntable. A small portable compressor will struggle with stiff tires.

Can it damage alloy wheels?

It has no leverless or plastic-protected mounting head, so alloy wheels need care with the demount bar and clamps. Shops doing a lot of premium alloy work usually want a machine with alloy protection.

Is it worth it over a changer without an assist arm?

If you regularly fit low-profile or run-flat tires, the assist tower saves time and effort on every hard sidewall. For basic steel-wheel work, a plain swing-arm changer does the same job with less to maintain.