A hub ring marked 73.1 → 67.1 mm is the correct sizing direction for a wheel with a 73.1 mm center bore being installed on a vehicle hub measuring 67.1 mm. The larger number is the wheel-side outside diameter (OD); the smaller number is the vehicle-side inside diameter (ID).
Confirm the wheel center bore: 73.1 mm
The wheel center bore is the circular opening through the center of the wheel. For this application, that opening must be 73.1 mm, normally listed in the wheel manufacturer’s specifications.
The hub ring’s outside diameter must match this wheel bore:
- Wheel center bore: 73.1 mm
- Hub ring outside diameter: approximately 73.1 mm
Do not select a ring based only on the vehicle hub measurement. A 67.1 mm ring ID may fit the vehicle, but the ring will not be properly supported if its OD does not match the wheel bore.
Check the wheel specification rather than relying on a visual measurement. Aftermarket wheels can have similar-looking center openings with different nominal dimensions. If the bore is not documented, measure the opening with suitable precision. A general-purpose ruler is not accurate enough for selecting a close-fitting hub-centric ring.
Also confirm that the bore is a straight cylindrical surface where the ring will sit. Some wheels have a chamfer, bevel, stepped bore, or a retaining groove. The ring must be shaped for the available seating area and must not bottom out against an internal step before the wheel is fully supported.
Confirm the vehicle hub: 67.1 mm
The vehicle hub is the raised circular pilot on the vehicle’s hub or brake rotor assembly. For this fitment, the hub pilot should measure 67.1 mm.
The hub ring’s inside diameter must match that vehicle-side pilot:
- Vehicle hub diameter: 67.1 mm
- Hub ring inside diameter: approximately 67.1 mm
The measurement should be taken from the clean, usable pilot surface–not from a rust ridge, damaged edge, dust cap, or nearby part with a different diameter. If the hub has corrosion or a coating, remove loose material before measuring and fitting the ring.
A nominal 67.1 mm hub dimension does not guarantee that every physical measurement will read exactly 67.10 mm. Manufacturing tolerances, measuring tools, paint, powder coating, and corrosion can affect the fit. The correct ring should slide onto the hub pilot with controlled hand pressure. It should not wobble noticeably, and it should not require hammering or force that could damage the hub or ring.
Why the sizing direction is 73.1 → 67.1
A hub-centric ring fills the clearance between a larger wheel bore and a smaller vehicle hub. Its dimensions are therefore specified from the wheel side to the vehicle side:
| Fitment feature | Required dimension |
|---|---|
| Wheel center bore | 73.1 mm |
| Ring outside diameter | 73.1 mm nominal |
| Vehicle hub pilot | 67.1 mm |
| Ring inside diameter | 67.1 mm nominal |
The diameter difference is:
73.1 mm − 67.1 mm = 6.0 mm
That creates a nominal radial gap of approximately:
6.0 mm ÷ 2 = 3.0 mm
The ring occupies this annular space and centers the wheel on the vehicle hub pilot. It does not convert a different wheel bore or hub diameter into this fitment. For example, a ring with a 67.1 mm outside diameter is not the correct substitute for a ring with a 73.1 mm outside diameter, even if its inside diameter is 67.1 mm.
A hub-centric ring also does not correct an incorrect bolt pattern, wheel offset, brake clearance, thread specification, or load rating. Those must be checked separately before installation.
Check tolerance, profile, and material
Nominal sizing is only the starting point. Before buying, match the following details.
Fit tolerance
The ring OD must fit the wheel bore closely enough to prevent visible movement, while the ID must fit over the vehicle hub without excessive looseness. A properly sized ring generally installs by hand or with light, even pressure. Avoid a ring that:
- Cannot enter the wheel bore because the OD is too large
- Rocks significantly inside the wheel bore
- Will not slide onto the hub after the surfaces are clean
- Requires striking with a hard tool
- Leaves a visible gap between the ring and either mating surface
Do not assume that a slightly undersized ring is acceptable because the wheel fasteners will pull the wheel into position. That can leave the wheel off-center during installation and may produce vibration or uneven seating.
Cross-section and seating depth
The ring must be deep enough to engage the wheel bore and the vehicle hub, but it must not interfere with:
- The back of the wheel
- The hub face
- Brake components
- A hub dust cap
- A step or internal shoulder in the wheel bore
Some rings have a lip or stepped profile; others are plain cylindrical rings. Match the profile to the wheel and hub geometry. A ring that fits the diameter but bottoms out before the wheel reaches the hub face is not a correct fit.
Material
Common hub-ring materials include engineered plastic and aluminum. Either can be suitable when correctly dimensioned and compatible with the wheel and operating conditions.
Plastic rings are typically lightweight and resistant to some forms of galvanic corrosion. Aluminum rings can provide a rigid, durable fit but require attention to corrosion where aluminum contacts steel, especially in wet or salted environments. Material alone does not compensate for incorrect dimensions or poor seating.
If the wheel manufacturer or ring supplier specifies a temperature, load, or application limit, follow that information. Do not select by material name alone.
Installation and corrosion checks
- Remove the wheel and clean the vehicle hub pilot, wheel bore, and wheel mounting face. Remove loose rust, dirt, old coating, and debris without removing sound metal.
- Test-fit the ring on the vehicle hub. It should sit squarely and fully on the pilot.
- Test the ring in the wheel bore if practical. Confirm that it does not protrude in a way that prevents the wheel from sitting flat against the hub face.
- Check that the wheel mounting face contacts the vehicle mounting face without a gap. The ring must not act as a spacer.
- Install the wheel and start all fasteners by hand. Do not use the fasteners to force a misaligned wheel into position.
- Tighten the wheel fasteners in the vehicle or wheel manufacturer’s specified sequence and torque. Do not apply lubricant to tapered or ball-seat surfaces unless the applicable manufacturer specifically requires it.
- After installation, confirm that the wheel turns freely and that there is no interference. Follow the vehicle or wheel manufacturer’s guidance for any required torque recheck.
For corrosion prevention, keep the mating surfaces clean and dry. Do not paint over the hub pilot or wheel bore as a way of correcting looseness. If an anti-seize or corrosion-protection product is used, apply it only where appropriate and sparingly; excess material can prevent full seating or migrate onto braking and fastener seating surfaces. Aluminum rings that have become seized should be removed carefully rather than pried against brake or wheel components.
73.1 to 67.1 product-selection checklist
Before ordering, confirm all of the following:
- The wheel center bore is 73.1 mm.
- The vehicle hub pilot is 67.1 mm.
- The ring specification is written 73.1 mm OD × 67.1 mm ID or 73.1 → 67.1 mm.
- The ring profile matches the wheel bore, including any chamfer, step, or retaining feature.
- The ring fits the full available seating depth without contacting unrelated components.
- The actual wheel and hub surfaces are clean and free from damaging corrosion.
- The material is suitable for the vehicle’s climate and use.
- The ring does not alter the wheel’s bolt pattern, offset, or brake-clearance requirements.
- Wheel fastener type, thread engagement, seating style, and torque are separately confirmed.
- The ring and wheel seat fully without force, rocking, or visible gaps.
For the stated dimensions, the sizing direction is unambiguous: choose a 73.1 mm outside diameter hub-centric ring with a 67.1 mm inside diameter.
