Hi Longsheep
Actually I was looking at my Centurion (Chris Ludwig kit) road wheels (51mm) yesterday. The're about 1mm larger than the Chief road wheels (50mm), the gap between the pairs is narrower than Chief too, but should not be too much of a problem, though the stalk behind the road wheels is shorter on Cent, so a spacer would be required. The bigger issue would be the axles - 2.5mm bolt on the Cent, about 3mm odd on Chief, though that may be fixable with bearings with greater ID, same OD. Didn't check the hubs though - Cent hubs are domed, Chief hubs pointed.

Mal

Chief - Upper, Cent - Lower

Cent Roadwheels - 51 mm

Chief Roadwheels with pointed hub insert, which can be pried out

Cent with rubber tyres left, Chief right, wider gap between wheels

Chief Horstmann bogie, plastic axle

Cent left 51 mm, Chief right 50 mm

Cent left, Chief right with greater spacing

Cent left, Chief right - back of roadwheels showing stalks, Chief lomger

Cent Horstmann Bogie, 2.5mm bolt forms axle, note bearings in roadwheel centres