Check Aeroclub, they have a wide range of WW1 wheels, guns and other
thingies in white metal:
Assuming my match is correct, 11 cm is about 4.25 inches. That's RC scale
sized accerssories. I know there are wheels out there for RC scale
aircraft about that size.
You didn't say say whether or not you wanted bare spokes or the covered
wheel type. Williams Bros makes a line of scale wheels, including a WW1
type (covered). I'm pretty sure they make a 4+ inch wheel.
There's also an outfit in Arizona that sells 1/4, 1/5, and 1/6 scale WW1 RC
aircraft. They have a line of accessories as well I think The company is
Arizona Model crafters, or something like that.
A post on rec.models.rc.air will probably get you lots more responses.
4. Wire Wheels
5. Wire Wheels?
7. wire wheels?
12. PE Wire Wheels