Originally Posted by
zaroba
Mallard stamped on the gear so that's likely the brand, and looking closely, it needs a tool that has at least 30 teeth or rather grooves. That caliper doesn't seem to be supplied by Park Tool or other common modern companies but it is a nearly 50 year old bike. Guess I'll just buy a new gear set to go along with the new wheel.
That's an old shop only tool and the freewheel won't fit anything modern wheel, it used a completely different design. I suspect you're going to need shop help or someone who knows what they're doing. Bolt on vs quick release is going to matter, the spacing between the dropouts might need to be expanded, most modern wheels are 130mm even if they're freewheel. A freewheel bolt-on wheel can be narrowed down to fit sometimes but usually requires a shop with random spare parts. Unless you're all about collecting and preserving or this bike has some particular special value to you, I'd recommend looking at a newer used bike. Needed wheels, freewheels, front der, etc you're liable to spend as much as you would for a used late 90s, early 2000s road bike and the two bikes in terms of tech and quality probably won't be comparable.