Pro-Bolt M24 Stainless Steel Flanged Axle Nut. Titanium Flanged Axle Nut M24 Rear Wheel Black Yamaha YZF-R6 2017-2025. Stainless Steel Axle Nut M24x(1.50mm) Rear Wheel. Pro-Bolt’s Stainless Steel Flanged Axle Nut is the ideal choice for anyone looking to upgrade their fasteners with a polished, durable, and corrosion-resistant option.