88503 Single Row Extended Race Ball Bearing Rubber Sealed WJB
Bearing has a17mm ID (d), 40mm OD (D), 12mm wide outer race (Bo), and 16.6mm inner race (Bi).
88503 WJB Radial Ball Bearing W2 Felt Seals By Premium Bearing Source
You will find that the ball bearing stays put even when things get a bit rough.