8-172 BLACK FKM 90D BACK-UP RING

Ordered as VBU90172, this is an AS568-172 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 8.237 in (209.22 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 8.443 in (214.45 mm). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Expect good resistance to engine and transmission fluids, petroleum oils and fuels, and many acids. Viton® (FKM) offers very low compression set at elevated temperature, excellent resistance to compression set and permeation. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Exposure to ketones and esters or hot water and steam will shorten service life.

You will find this material specified across aerospace, automotive fuel systems, and chemical processing.

Order part number VBU90172, sold individually. Nominal inside diameter is listed as 8 1/4 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.