BBS RS Flat Face & Step Lip Rebuild

BBS RS wheels are classic 3-piece modular wheels made up of a center face, inner barrel and outer lip, all bolted together and sealed. This design allows rebuilding, resizing and refinishing, but also means correct assembly is critical.

If assembled incorrectly, the wheel can leak air, come loose or fail under load. Below is a translated practical guide based on original German BBS documentation.

Good practices:

  • Always tighten bolts in a cross pattern
  • Always torque in multiple stages
  • Assembly must be clean and dry at sealing surfaces
  • Re-check bolts after initial use (recommended practice)

BBS RS Flat Face Assembly Tutorial (Flachbett)

Flat face (also called flat-bed) BBS wheels have a relatively shallow lip and a more traditional profile. Assembly is straightforward but sealing and bolt torque are critical.

1. Prepare tire seating surface
Apply tire mounting paste to the tire bead seat according to the tire manufacturer specifications.

2. Install valve into outer lip
Insert the metal valve (Alu-Ventil) into the outer lip (outer wheel half) and tighten the nut moderately.

3. Insert inner barrel into tire
Press the inner barrel into the tire.

4. Install sealing ring (dry installation)
Insert the sealing ring.
It must be: clean, dry & installed without any sealant

(alternatively you can use suitable sealant for wet installation) 

5. Fit outer lip and align components
Insert the outer lip (with valve installed) into the tire and press it together with:

  • inner barrel
  • sealing ring

Ensure:

  • bolt holes align
  • sealing ring sits correctly between both halves

6. Install center and bolts
Insert the wheel center into the assembly.
Insert all connecting bolts into the bolt holes.

7. Pre-tighten bolts
Stand the wheel vertically.
Install self-locking M6 nuts with washers and tighten to approx.:

  • 10 Nm (initial tightening)

8. Final torque (two stages)
Using a torque wrench, tighten all nuts:

  • in 2 passes
  • evenly (cross pattern)

Final torque: 15–16 Nm (use small 1/4″ torque wrench)

9. Inflate tire and check
Inflate the tire and check the bead seating.

Then reduce pressure to normal operating level.

Flachbett RS 3 piece wheel assembly step by step

BBS RS Step Lip / Deep Dish Assembly (Tiefbett-Rad)

Step lip wheels require more precise assembly. Sealing and torque values are higher and must be followed carefully.

1. Prepare center with threaded inserts
Install threaded inserts into the center if required.
Place the center on a stand for assembly.

2. Install outer barrel and valve orientation
Insert the outer barrel into the tire.

If brake cooling (Lüfter) holes are present:

  • rotate the valve position from the outside inward
  • shift it approx. 5 holes to the left

(This is a very specific BBS alignment requirement often ignored.)

3. Install sealing ring (dry)
Insert the sealing ring into the outer barrel.

Requirements: clean, dry and no sealant or lubrication

4. Install inner barrel and align
Place the inner barrel so that:

  • bolt holes align with outer barrel
  • sealing ring sits correctly between both halves

If assembly is done from the inside, the sequence of parts may be reversed.

5. Insert bolts and pre-tighten
Insert all connecting bolts with washers.

Tighten initially to approx.:

  • 10 Nm

6. Final torque (two-stage tightening)
Using a torque wrench, tighten all bolts:

  • in 2 passes
  • evenly in cross pattern

Final torque:

  • 15–16 Nm

7. Install valve and remove from stand
Remove the wheel from the stand.
Install the valve if not already fitted.

8. Install airflow cover (if present)
If equipped, install the airflow cover (Lüfter) on the outside of the wheel.

Ensure:

  • valve aligns with cutout
  • secure with 5 bolts M6 x 12 DIN 912 (8.8 grade)

9. Mount tire properly
Mount the tire using correct mounting direction as specified by the tire manufacturer.

10. Inflate and inspect
Inflate the tire and check:

  • bead seating
  • air tightness

Then reduce pressure to normal operating level.

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Tiefbett BBS RS 3 piece wheel assembly tutorial