What Is a Bolt Pattern?

Bolt pattern is the single spec that has to match before anything else about a wheel matters. It's written as two numbers, like 8x170 or 6x139.7. The first number is how many wheel studs the hub has. The second is the diameter, in millimeters or inches, of the imaginary circle that passes through the center of every stud. Get either number wrong and the wheel will not mount, full stop — it isn't a matter of offset or backspacing making it "close enough."

This article covers how bolt circles are measured, why the same pattern shows up in both metric and inch notation, the patterns you'll actually run into on trucks and Jeeps, and where adapters fit into the picture. For sizing basics that pair with this, see how to read a wheel size.

Stud count first, bolt circle second

Stud count is easy — count the holes. Trucks and Jeeps run 5, 6, 8, or 10 lugs depending on gross vehicle weight rating. Half-ton trucks and most SUVs and Jeeps run 5 or 6 lugs. Three-quarter-ton and one-ton (HD) pickups run 8 lugs. The heaviest chassis-cab trucks, like the Ford F-450 and F-550, run 10 lugs on the front axle. More studs generally means more clamping capacity for a heavier truck, not a styling choice.

The bolt circle diameter (BCD) is the trickier number because you can't just measure hole to hole in most cases. On patterns with an even number of studs — 6, 8, or 10 — the two studs directly across from each other sit exactly on the diameter, so you can measure center-to-center between them and read the BCD straight off a tape measure or caliper.

Measuring a 5-lug pattern

Five-lug patterns don't have a stud directly opposite another one, so the direct-measurement trick doesn't work. The standard shop method is to measure from the center of one stud to the outer edge of the stud that is two positions away (skipping one in between). That center-to-outer-edge distance on a 5-lug hub approximates the true bolt circle diameter. It's a workaround, not an exact formula, which is why most people cross-reference the number against a known pattern chart rather than trust a single field measurement for an order.

Metric vs. inch notation

The same bolt circle is often published two ways. 6x135 and 6x5.315" are the same pattern (Ford's F-150 pattern used since 2004). More commonly you'll see 6x139.7 written as 6x5.5" — 139.7 mm is exactly 5.5 inches, and this is the pattern shared by most half-ton GM, Toyota, and Nissan trucks and SUVs. Wheel manufacturers and spec sheets mix the two conventions, so when you're cross-shopping, convert before you assume two listings are different patterns. A quick check: multiply an inch figure by 25.4 to get millimeters, or divide millimeters by 25.4 to get inches.

Some wheels are dual-drilled — machined with two overlapping bolt circles, like 6x135/6x139.7 — so one wheel physically fits hubs of either pattern. It's a legitimate feature on universal-fit aftermarket wheels, not a workaround, since every hole is drilled to the real diameter for each pattern rather than stretched or shared.

Common truck and Jeep bolt patterns

The table below covers the patterns we see most often on the trucks, SUVs, and Jeeps people actually bring in. Trims and years vary, so treat this as a starting reference, not a final answer for your specific build.

Notice that pattern alone doesn't tell you SRW vs. DRW, or front vs. rear on a dually — some of these heavy-duty trucks use different wheels front to rear. If you're building out a dually setup, dually wheels explained covers those front/rear differences and the rear offset requirements that go with them.

Bolt pattern isn't the whole fitment picture

Matching the bolt pattern gets the studs through the holes. It doesn't guarantee the wheel clears the brake caliper, sits at a usable offset, or centers correctly on the hub — that last part is center bore, a separate spec that matters just as much for how the wheel actually runs. Two vehicles can share a bolt pattern and still need different hub-centric rings or different offsets entirely.

Why adapters are a compromise, not a fix

Bolt pattern adapters (also called wheel spacers with a pattern change) bolt to your existing hub and give you a new set of studs in a different pattern, letting you run wheels that otherwise wouldn't bolt up. They work, but they add real drawbacks: extra stack-up pushes the wheel further out and changes effective offset, they add another interface with its own torque spec that needs rechecking, and they add unsprung weight and a failure point that a direct-fit wheel doesn't have. On a truck that tows or hauls, most shops treat adapters as a short-term bridge rather than a setup to run indefinitely. If a wheel you want doesn't come in your native pattern, it's usually worth looking at what is actually offered for your bolt pattern before adding an adapter to the equation.

How to shop by bolt pattern without guessing

• Start from your vehicle when possible — shop by vehicle filters wheels to your documented pattern instead of asking you to self-report a measurement.
• If you already know your pattern, browse it directly from shop by bolt pattern, which lists every pattern we carry.
• If you're measuring in the driveway, use the direct across-stud method on even lug counts and the skip-one method on 5-lug hubs, then confirm against a published spec for your vehicle.
• Double-check SRW vs. DRW and front vs. rear on any 8-lug-or-larger heavy-duty truck — the pattern number alone doesn't distinguish them.
• Once pattern is confirmed, move on to center bore and offset before finalizing a wheel choice.

Bolt pattern is where fitment starts, not where it ends. Nail this number down, then work through bore and offset before you check out — it's the difference between a wheel that bolts on and looks right, and one that bolts on and rubs.