BROX Silver 15-Spoke Beadlock Forged Wheels
Off-Road Beadlock · Silver
2021 Mazda BT-50 Wheels & Rims: Bolt Pattern, Offset & Sizes
Fitting Mazda BT-50 wheels? This page gives the 2021 Mazda BT-50 bolt pattern (6x139.7), centre bore, factory rim size and the offset range for aftermarket and forged Mazda BT-50 rims: the same spec sheet ANKUSI uses when machining forged wheels for this car.
Quick answer: The 2021 Mazda BT-50 uses a 6x139.7 bolt pattern with a 100.1 mm centre bore and M12x1.5 lug nuts. Factory wheels: 18x7.5J ET33. For aftermarket wheels, 18x9J ET20 sits flush.
Forged wheels for the 2021 Mazda BT-50 — drilled 6x139.7 with a 100.1 mm centre bore, built to the offset you choose. From $220 per wheel, made to order in 20–25 days.
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Mazda BT-50 (2021): 6x139.7 bolt pattern, 100.1mm center bore, OE 18x7.5J ET33. Forged wheel fitment specs from ANKUSI.
Bolt Pattern6x139.7
Wheel Bolt/NutM12x1.5 Nut
Center Bore100.1mm
Wheel Load Rating900–1250 kg/wheel (SUV segment reference)
Year2021
Category6-Lug Off-Road (Beadlock)
✓ Data check: the bolt pattern and center bore on this page match an independent fitment reference. Last reviewed September 18, 2026. How we verify
Wheel Size & Offset at a Glance
| Configuration | Wheel Size & Offset |
|---|---|
| Factory (OE) | 18x7.5J ET33 |
| Flush Fitment | 18x9J at ET20 offset |
Forged Wheel Designs for the Mazda BT-50
Every design below is forged to order, so it can be machined to the Mazda BT-50's 6x139.7 bolt pattern and 100.1 mm center bore, with the width and offset calculated for your setup.
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How to Read Wheel Offset & Measurements
Use these two references before ordering: the left diagram shows where each spec (PCD, center bore, offset, width and diameter) is measured on the wheel; the right diagram shows how positive, zero and negative offset shift the wheel face relative to the hub centerline.
ANKUSI Engineering Expert Advice
Off-road platforms put real, repeated impact loads through the wheel that street-only vehicles never see, so the factory strength margin on the Mazda BT-50 isn't a formality — it's load-bearing in a literal sense. Forging matches that margin at a lower rotational weight than an equivalent cast wheel, which matters both on the trail and on the highway miles between trailheads.
The Mazda BT-50 ships from the factory on a 6x139.7 bolt pattern with a 100.1mm center bore and a 18x7.5J ET33 wheel. Our flush reference for the Mazda BT-50 is 18x9J ET20.; our maximum aggressive reference is 20x9.5J ET15. — beyond that, expect clearance issues against the fender liner without further modification.
Mazda BT-50 OE Wheel Specs
The Mazda BT-50 ships from the factory on 6x139.7 bolt pattern wheels with a 100.1mm center bore. The stock wheel size is 18x7.5J ET33, offering a balanced ride that suits most owners without any rubbing or clearance concerns.
Why the factory spec works for most owners:
- Balances ride comfort with steering response and highway efficiency.
- Wide tire and wheel availability at the factory diameter keeps replacement costs low.
- Lower unsprung weight than larger aftermarket wheels helps ride quality and acceleration.
- Guaranteed clearance against brake calipers and suspension components.
ANKUSI builds these wheels — we are the forging factory, not a reseller. For the Mazda BT-50 (2021) we drill the 6x139.7 pattern and cut the centre bore to 100.1mm on our own CNC line, so the wheel hub-centres on the car with no spacer rings, in whatever diameter, width and offset you specify.
Converting these ET figures to backspacing? Use the wheel offset and backspacing calculator.
The figures on this page are part of our open wheel fitment dataset — 10,093 vehicles, free to download, CC BY 4.0.
Offset and Backspacing: Factory Wheel vs Options
Backspacing ≈ width/2 + ET/25.4 + 0.5 in. "Inward" means closer to the suspension; "outward" means closer to the fender lip.
| Setup | Size | ET | Backspacing | Inward vs OE | Outward vs OE |
|---|---|---|---|---|---|
| Factory (OE) | 18x7.5J | ET33 | 5.55 in (141 mm) | — | — |
| Flush | 18x9J | ET20 | 5.79 in (147 mm) | +6 mm | +32 mm |
| Maximum | 20x9.5J | ET15 | 5.84 in (148 mm) | +7 mm | +43 mm |
Vehicles With the Same Hub as the Mazda BT-50 (6x139.7, 100.1 mm Bore)
In our database, 21 other vehicle entries from 7 makes use exactly the same 6x139.7 bolt pattern and 100.1 mm center bore. Factory wheels from these cars bolt on and center on the hub without rings; offset and width still have to be checked.
6x139.7 is used by 4.0% of the vehicle pages in our English fitment guide (258 of 6,503); 8.5% of those also use a 100.1 mm center bore.
Hub-Centric Rings for a 100.1 mm Center Bore
A wheel with a center bore larger than 100.1 mm needs a hub-centric ring. The most common combinations:
| Wheel bore | Ring size |
|---|---|
| 106.1 mm | 106.1 → 100.1 mm |
| 108.1 mm | 108.1 → 100.1 mm |
| 110.1 mm | 110.1 → 100.1 mm |
| 130.1 mm | 130.1 → 100.1 mm |
ANKUSI forged wheels are bored to exactly 100.1 mm for this vehicle, so no ring is needed.
Frequently Asked Questions
What bolt pattern (PCD) does the Mazda BT-50 use?
The 2021 Mazda BT-50 uses a 6x139.7 bolt pattern.
How many lug bolts does the Mazda BT-50 use?
The Mazda BT-50 uses a 6-lug bolt pattern (6x139.7), so you need a 6-lug forged wheel to bolt straight on.
What is the center bore size on the Mazda BT-50?
The Mazda BT-50's center bore is 100.1mm. If an aftermarket wheel has a larger center bore than this, hub-centric rings are recommended so the wheel centers on the hub itself rather than relying on the lug bolts alone.
What size are the factory (stock) wheels on the Mazda BT-50?
Factory wheels on the Mazda BT-50 are 18x7.5J ET33.
What does a flush wheel fitment look like on the Mazda BT-50?
For a flush look with minimal to no rubbing, we recommend 18x9J at ET20 offset as a starting point on a stock or mildly lowered Mazda BT-50.
Do I need wheel spacers for my Mazda BT-50?
No. ANKUSI forges each wheel to your exact target offset, including the flush or max specs above, so you get the correct fitment without stacking spacers. Spacers are typically only used to push out an existing OE-offset wheel without replacing it, which isn't necessary when you're ordering a custom-offset forged wheel.
How do I calculate wheel backspacing for my Mazda BT-50?
Backspacing (in inches) = wheel width (in) ÷ 2 + offset (mm) ÷ 25.4 + 0.5 (flange allowance). For example, the flush spec above works out to roughly 5.79" of backspacing.
What's the difference between wheel offset and backspacing?
Offset is the distance in millimeters from the wheel's true centerline to its mounting face (positive offset pulls the wheel in, negative pushes it out). Backspacing is the distance in inches from the mounting face to the back edge of the wheel barrel. They describe the same fitment from two different reference points, which is why ANKUSI lists both above — some shops and tuning guides quote offset, others quote backspacing.
Can I run staggered wheels (different sizes front and rear) on my Mazda BT-50?
The Mazda BT-50 runs the same wheel size front and rear from the factory, so staggered fitment is not required. ANKUSI can still forge a staggered set (wider rear) on request if you want a more aggressive stance.
Sources and Last Update
Data checked against: avtoreference.com.
This record is part of the open ANKUSI Wheel Fitment Dataset (DOI 10.5281/zenodo.23241521, CC BY 4.0).
Other cars on the same factory size: 18x7.5 wheels · 18 inch wheels.
Compiled by the ANKUSI Wheels engineering team, an IATF 16949 and ISO 9001 certified forged wheel factory in Guangzhou.