Original BMW Drive Belt Deflection Pulley for BMW M2 Competition, M3, and M4 (2015–2021)

Original BMW deflection pulley 11-28-7-848-607 is the accessory drive belt idler pulley for the S55 engine in the F80 M3, F82 and F83 M4, and F87 M2 Competition. An idler pulley guides the belt along its path around the engine-driven accessories and works with the tensioner to keep belt tension steady. BMW shows production of this pulley beginning in March 2014, and it is made in Germany. It is sold individually as one pulley.

Original BMW Parts carry a 24-month parts warranty.

The idler is easy to overlook during belt service, but it matters as much as the tensioner. In most cases the recommendation is to replace the idler pulley at the same time as the belt tensioner. BMW uses this one number across the S55 cars, including the facelift F80, F82, and F83 models, the M4 GTS, and the M4 CS, so there is no early and late version to sort out within the fitment years. On the M2, BMW applies it to the Competition only, since that model uses the S55.

Technical Details

• Manufacturer: BMW (Original BMW part)
• Part number: 11-28-7-848-607
• BMW name: deflection pulley
• Engine: S55
• Chassis: F80, F82, F83, F87
• Production start: March 2014
• Made in Germany
• Sold individually, one pulley
• Warranty: 24-month parts warranty

Installation & Tuning Notes

Plan to replace this idler together with the belt tensioner.

Common Questions

What are the signs of a failing idler pulley?
Look for belt squealing, chirping or grinding from the pulley bearing, odd or uneven belt wear, and visible wear or grooves on the pulley. A pulley that sits misaligned against its mounting surface is another sign.

Should I replace the tensioner too?
In most cases, yes. Replacing the idler and tensioner together is the usual recommendation.

Talk to PMB Performance about the rest of your S55 belt drive service.

Fitment & Compatibility

Use the fitment table below to confirm year, make, model, submodel, and any notes tied to your exact vehicle. Pay close attention to engine, chassis, position, and option-specific details before ordering. PMB Performance has spent over 20 years matching parts to vehicles and can verify this against your VIN.