Bolt pattern
The number and spacing of mounting bolts must agree. A mismatch means the wheel is not a direct bolt-on fit.
BMW FITMENT CHECKER
Fitment, made
measurable.
Compare wheel position, tire geometry, and documented chassis evidence in one precision workspace before you order or install.LIVE FITMENT CHECKER
Your comparison
FULL COMPARISON
Every calculated measurement
Current setup and proposed setup, side by side.MeasurementCurrentProposed
Overall diameter
Rolling circumference
Sidewall height
Tire width
Revolutions per mile
Outer position / poke
Inner position / inset
Speedometer difference0.0%
At indicated speed
At indicated speed
At indicated speed
Ride-height changeBaseline
Arch-gap changeBaseline
BMW CHASSIS EVIDENCE
Wheel platform → your BMW
Start with catalog evidence, then verify the physical numbers that decide whether a wheel actually clears your car.
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SELECT TWO CHASSIS CODES
Compare the wheel platform against your BMW.
Choose where the wheel came from and the BMW you want to install it on. This checks local catalog bolt-pattern evidence first, then points you to the measurements that still need verification.
WHAT THE RESULT MEANS
A matching diameter is not enough
Center bore
The wheel must seat concentrically on the hub. Hub-centric rings can only address a larger wheel bore—not a smaller one.
Width and offset
These determine how far the wheel sits inward and outward. The wrong combination can contact suspension or bodywork.
Tire diameter
The mounted tire affects speedometer accuracy, gearing, xDrive operation, and physical clearance.
Brake clearance
Diameter alone does not prove caliper clearance; spoke shape and barrel design also matter.
Load and hardware
Confirm wheel load rating, bolt seat, bolt length, axle configuration, and local approval requirements.
TIRE SIZE DECISION GUIDE
Use the calculator before you shop for tires.
The safest tire recommendation is the one recorded for your exact BMW model, wheel size, axle, and load rating. This page helps you compare geometry; it does not guess an approved tire size.Start with the BMW tire size
Use the tire size shown on the door placard, owner information, BMW wheel record, or verified wheel page. For staggered setups, front and rear tires may be different.
Keep rolling diameter close
A taller or shorter tire changes ride height, arch gap, speedometer reading, gearing, and xDrive sensitivity. The calculator flags diameter and speedometer change so you can reject bad candidates early.
Check width, ET, and clearance together
Wheel width and offset decide inner suspension clearance and outer poke. Tire section width also varies by manufacturer, so a matching size code is not a clearance guarantee.
Buy only after the full spec matches
Before ordering tires, confirm load index, speed rating, run-flat requirement, axle position, brake clearance, body clearance, and local inspection rules for your BMW.
What does speedometer error mean?
Changing tire diameter changes how far the car travels per wheel revolution. If the proposed tire is taller, the car may travel faster than the indicated speed; if it is shorter, the indicated speed may read high.
Can a G20 wheel fit an E39?
Not from wheel style alone. Compare bolt pattern, center bore, width, ET, tire diameter, brake clearance, and hardware. The calculator helps with width, ET, and tire diameter, but it does not prove hub bore or brake clearance.
Is lower offset always more aggressive?
Usually lower ET moves the wheel outward, but total position depends on both width and offset. A wider wheel with the same ET can reduce inner clearance and increase outer poke.
Why not automatically recommend tires?
BMW tire fitment depends on model, axle, trim, load rating, tire construction, and market rules. This library should show recorded tire sizes and calculator math, then let the buyer choose from documented options.
KNOW THE NUMBERS?