This is a solid customizable replacement for the standered 2 inch (50mm) office chair wheel with a 8mm pin . The wheels are very solid and my prototypes have stood up to 3 months of abuse with persons up to 250Lb . The wheel support in its current state is standing up very well however i have only 1 week of testing for the wheel support structure. I have additional fender designs in the works as well as wheel covers or hubcaps. Also another wheel designed for 626ZZ bearings that would allow for a smaller axle M6 Axel bolt for those who may have a hand full of 626ZZ bearings on hand. Be the first on your block to have the coolest wheels around. If you only wish to replace your wheel you will need to remove the axle and drill out the wheel support to accept the M8 Bolt then You will need 2 608Z bearing, 1 M8 60mm bolt, 4 M8 washers, 1 M8 nylock nut (or standard nut with 1 drop of blue Threadlock), 10 M3 16mm Hex socket bolts, 10 M3 Nuts, 10 M3 washers. The wheels print well with ABS or PLA I sliced with CURA with 1.2mm Shell Thickness 1.2mm Top/Bottom Thickness. 20% infill. The rear bearing cover is part of the structural design of the wheel and must not be left out. It includes Nut traps that will allow a flush mount for the rear of the wheel so it will not interfere with the wheel support. If you wish to use Acorn nuts the nuts traps will allow the Socket bolt head to sit flush in the rear bearing cover. Important! When using the Wheel support structure I Have only had time to test it with PLA I sliced with CURA Shell Thickness of 1.5mm and 1.5mm Top and Bottom Thickness. 21% Infill you must use 1.5mm to allow for the internal support structures that i have designed into it to work . Also you must use the wheel support steam to reinforce the top of the wheel support. The fender is optional and only need 3 M3 10mm Hex socket bolts. It is very Important not to reorient items to slice them! I have laid them out in their proper orientation This project is still a work in progress and is still in the experimental stage if you print and use this wheel you do so at your own risk I take no responsibility for any damages or injury's that could result from the use of this project. If you have any questions or suggestions please leave them in the comments If there are other size stems you may have please let me know and i will make one for that size. Happy printing and please share your makes.