King Racing BMW M5 S85B50 main bearing set STDX

Key Features & Benefits – King Racing BMW M5 S85B50 main bearing set STDX

King Racing BMW M5 S85B50 main bearing set STDX for BMW M5 S85B50 5.0L 40V DOHC engines. Type: Main Bearing, supplied in the STDX variant.

STD vs STDX difference: STD is the standard sizing route, while STDX keeps the same sizing class but is intended to allow more oil clearance compared with STD. Choose STDX when your measurement-led build calls for more clearance than STD would deliver with your crank and housings. The full explanation is here: Difference between King Racing STD and STDX bearings.

When is this useful?

In an S85B50 rebuild, STD is used when measured clearances land on target with standard sizing, while STDX is used when the same engine setup needs more oil-clearance margin based on the measurements.

Technical specs

• Brand: King Racing
• Type: Main Bearing
• Application: BMW M5, S85B50, 5.0L 40V DOHC
• Size: STDX
• Country of origin: Israel
• Housing: 62.705–65.034 mm
• Length: 21.70 mm
• Max thickness: 2.496 mm
• Variant ID: MB-637XP-STDX

Selection & installation tips

• Size choice: Use STD when measured oil clearance matches your target; use STDX when you need more oil clearance for the same engine build plan.
• Measurement-led mock-up: Measure crank main journals and housing bores, then confirm oil clearance during mock-up.
• Bearing seating: Inspect saddle surfaces and bearing seating because poor seating changes contact and clearance.
• Clean assembly: Clean oil passages and mating faces, then use assembly lube before first start.
• Mock-up rotation: After tightening, confirm free crank rotation and check for any tight spots.

Before final assembly, confirm whether STD or STDX fits your measured clearances and seating, then compare them to the technical specs listed above.