MINI factory wheel bolts are 12mm in diameter and 32mm in length. If you are not using spacers, or using spacers up to 10mm, you need to use 40mm studs. For spacers from 15mm to 20mm you need to use 50mm studs. For spacers 25mm and larger you will be supplied special bolts to mount the spacers to the hubs. The studs for these applications should then be 40mm. The studs and nuts are sold as individual items. Purchase enough studs and nuts for your model vehicle. A couple of extra lug nuts to keep in your glove box is also a wise move.