Hey Rivet, Your memory serves you right almost. Differing wheel sizes ie 46 and 49 diameter are permissible in accordance with the MM on the main landing gear of the smaller busses but remember to reprogram the BSCU. Also intermixing of tyre types is allowed between bias and radial tyres but once again consult mm. Intermixing of nosewheels with differing tread patterns usually leads to complaints from the jockeys of shimmy. I dont think that there is any allowance for different wheel diameters on nose landing gear though.
Cheers
HST
