How to Measure Wheel Stud Pattern? | Measure BCD/PCD Accurately

The wheel stud pattern — also called the bolt circle diameter (BCD) or pitch circle diameter (PCD) — is the measurement that determines whether a set of wheels will mount to your hub. One wrong number means wheels that wobble or won’t bolt up at all. The method differs by lug count, and the result is written in a standard format like 5×114.3 mm or 4×100 mm.

Count The Lugs First

Start with the simplest step: count the number of studs or lug holes on the hub. Most cars and light trucks use 4, 5, 6, or 8 lugs. The count tells you which measuring method to use and becomes the first number in your pattern (5×??.?, 4×??.?, etc.). Write it down before you pick up a tape measure.

If you’re measuring on the vehicle, safely support it on jack stands before removing the wheel. Clean any rust, dirt, or old grease off the hub face — debris can throw off your reading by a millimeter or more.

Even Patterns (4, 6, 8) — Measure Center To Center

For hubs with an even number of lugs, the measurement is straight across. Place the end of a tape measure or ruler at the center of one stud hole and read directly to the center of the stud hole opposite it. That distance is the bolt circle diameter.

On a 4-lug hub the opposite hole is obvious — it sits 180 degrees around the hub. On 6 and 8-lug patterns, look for the stud that is directly across the center of the hub, not the one next to it. Common even-pattern diameters range from 4×100 mm on many small cars to 8×170 mm on heavy-duty trucks. TireRack’s fitment guidance confirms this center-to-center method for all even lug counts.

The 5-Lug Pattern — Do NOT Measure Center To Center

A 5-lug hub has no hole directly opposite any other hole, so center-to-center measurement gives a wrong number. Summit Racing’s instruction sheets explicitly state: do not measure center to center on 5-lug patterns.

An alternative is the skip-a-stud method: measure from the center of one stud to the center of the stud two positions away (skipping one stud), then convert that distance using a reference chart. But the center-to-outside method is simpler, requires no chart, and works with any ordinary tape measure. The most common result across sedans and SUVs is 5×114.3 mm (also listed as 5×4.5 inches).

For regular DIY work, a standard tape measure is fine — just be steady and read carefully. If you measure patterns often, a dedicated wheel stud pattern tool makes the job repeatable and eliminates guesswork across different lug counts.

Common Mistakes That Throw Off The Reading

The most frequent error is measuring a 5-lug wheel center-to-center, which produces a number that doesn’t match any real pattern. On even patterns, people sometimes grab the adjacent hole instead of the one directly opposite, which shifts the reading by roughly 30 percent. Skipping the lug count and assuming the pattern also leads to errors — a 6-lug and 5-lug hub on the same vehicle platform need completely different measuring methods.

Dirt and rust on the hub can make the stud center hard to locate, so wipe the surface clean first. A wheel’s bolt pattern is also sometimes stamped inside the hub barrel or on the wheel backside — check for markings before measuring. If the number is already printed, you can skip the tape measure entirely and just confirm what you see.

The final result is always written as lug count × diameter in millimeters, for example 5×114.3 or 6×135. Trailer hubs and aftermarket wheels sometimes use alternative charts, so when in doubt, confirm against the vehicle or wheel manufacturer’s published spec.