This is a RC wheel I've designed for an old Land Cruiser 7 series but there are some other cars that use it. It is 1.9" standar size, but has a positive offset of 6mm to get narrower axle look. It uses standar 12mm hex.
This wheel has been tested with stock Axial SCX10 knuckles. If you use different knuckles be sure they have similar design as SCX10 ones, or due to possitive offset the wheel could hit them.
You will need five 1.6mm screws to get the final scale look (I use 1.6x8).
NOTE: It has no hub cap as shown in photos. A good option to get a similar look are some Junfac hubs: http://www.junfac.com/shop/index.php?main_page=product_info&products_id=492