I am relatively new to the defender world and I am not technically or mechanically minded at all. Please bear this in mind! I have just ordered and received new wheels an tyres for my 90 and they do not fit on to the hub. At the moment I have 15' standard modular steels with 30x9.5 (?) tyres. I have bought 16'x7' challenger steel wheels with larger tyres. I thought it would simply be a case of off with the old, on with the new howver this isnt the case. The hole in the middle of my current wheels is 5' with the hole in the middle of the challengers 4 3/4. Where have I gone wrong and is there any way to fix this with adaptors / spacers etc. I dont understand wheel offset etc so please be kind! I really dont want to have to send these back at great expense ...............