OS-20 (451mm) TNT M80 Double Wall Rim - 36H - Silver 24tpi OPC the Proline Micro has 18

the Proline Micro has 18 inch wheels for little legs

The SE Bikes Rad Series 3 piece style chromoly crank arm set utilizes a  standard 19mm x 150mm

and the axles are 3/8"

Fully welded joint construction

The Weinmann AS7X rim is a single wall aluminum rim

OS-20 (451mm) TNT M80 Double Wall Rim - 36H - Silver 24tpi OPC the Proline Micro has 18This is an OS20, race intended, double walled and pinned joint rim. It is 20" (451mm) for OS 20 tires only. This rim only works with OS 20 (451mm) tires not standard 20" (406mm) tires. If you do not know what OS 20 is, DO NOT BUY THEM! Use: BMX Race Size: OS 20in ISO: 451 Wall: Double Drilling: 36H Side: Machined Sidewall Material: 6061 T6 Valve: SV Width ID: 25mm Width OD: 30. 6mm ERD: 419 Color: Silver anodized