Original BMW Timing Chain Tensioner Guide Rail for BMW 1, 2, 3, 4, 5, 6, and 7 Series, M2, M3, M4, X1, X3, X5, X6, and Z4 (2006–2021)

BMW's chain tensioner and guide rail, part 11-31-7-585-020, is the Original BMW timing chain rail used in the N51, N52, N52N, N55, and S55 inline-six engines across the 1 through 7 Series, M2, M3, M4, X models, and Z4. On a chain-driven engine, the rails steer the timing chain between the crankshaft and camshaft sprockets, and the tensioner presses against its rail to take up slack as the chain runs. This rail weighs 360 grams. BMW began producing it in December 2008, and it now covers six-cylinder cars from the 2006 model year through the S55-powered M2 of 2021.

Original BMW Parts carry a 24-month parts warranty.

This number supersedes 11-31-7-542-836, and BMW marks it as interchangeable on older engines, so an early N52 car built with the previous rail takes the current part. The same rail spans the N52, N52N, N51, N55, and S55 engines, the last in the M2 Competition, M3, and M4.

Technical Details

• Manufacturer: BMW (Original BMW part)
• Part number: 11-31-7-585-020
• BMW part name: chain tensioner and guide rail
• Weight: 360 g (0.8 lb)
• Production start: December 2008
• Supersedes 11-31-7-542-836, interchangeable on earlier engines
• Engine codes: N51, N52, N52N, N55, and S55
• Sold individually
• Warranty: 24 months

Common Questions

Does it replace the older 11-31-7-542-836 rail?
Yes. BMW rates this number as interchangeable with the earlier rail, including on older engines.

Is the same rail used in the M2, M3, and M4?
Yes. BMW uses 11-31-7-585-020 on the S55 engine in the F87 M2, F80 M3, and F82 and F83 M4.

PMB carries Original BMW timing components for the N52, N55, and S55 families.

Fitment & Compatibility

Check the table below for the exact year, model, submodel, and any listed notes. With over 20 years of parts and fitment experience, PMB Performance can match this to your VIN.