{"id":4678,"date":"2026-10-13T03:53:07","date_gmt":"2026-10-13T03:53:07","guid":{"rendered":"https:\/\/tuhaoauto.com\/how-to-read-wheel-specs-pcd-offset-center-bore\/"},"modified":"2026-10-13T03:56:44","modified_gmt":"2026-10-13T03:56:44","slug":"how-to-read-wheel-specs-pcd-offset-center-bore","status":"publish","type":"post","link":"https:\/\/tuhaoauto.com\/es\/how-to-read-wheel-specs-pcd-offset-center-bore\/","title":{"rendered":"PCD, Offset (ET) and Center Bore: How to Read Wheel Specs Before You Order"},"content":{"rendered":"

Short answer:<\/strong> a wheel spec line such as 20×9.0J ET35 5×112 CB66.6<\/em> contains five separate decisions, not one. Diameter and width set the look and the tire choice; offset (ET) decides whether the wheel clears the suspension and the fender; PCD decides whether it bolts onto the hub at all; and the center bore decides whether it runs true or shakes at speed. Read them before you compare prices.<\/p>\n

The full spec line, decoded<\/h2>\n

Most wheel factories quote fitment in the same shorthand. What each part means, and what goes wrong:<\/p>\n\n\n\n\n\n\n\n\n\n\n
Term<\/th>\nWhat it means<\/th>\nExample<\/th>\nIf it is wrong<\/th>\n<\/tr>\n<\/thead>\n
Diameter<\/td>\nBead seat diameter, in inches<\/td>\n20 in<\/td>\nTire will not seat<\/td>\n<\/tr>\n
Width<\/td>\nBead-to-bead rim width in inches (J = bead seat profile)<\/td>\n9.0J<\/td>\nSidewall stretch; rubbing<\/td>\n<\/tr>\n
Offset (ET)<\/td>\nmm from the wheel centerline to the hub mounting pad<\/td>\nET35<\/td>\nRubs suspension or fender<\/td>\n<\/tr>\n
PCD<\/td>\nStud count + stud-circle diameter, in mm<\/td>\n5×112<\/td>\nWill not bolt on<\/td>\n<\/tr>\n
Center bore (CB)<\/td>\nMachined hole that centers the wheel on the hub<\/td>\nCB66.6<\/td>\nVibration at speed<\/td>\n<\/tr>\n
Load rating<\/td>\nMax load per wheel, as a load index<\/td>\nIndex 102<\/td>\nLoad safety risk<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Read it left to right: 20×9.0J ET35 5×112 CB66.6<\/strong> is a 20-inch wheel, 9.0 inches wide, 35 mm positive offset, five studs on a 112 mm circle, 66.6 mm center bore. If a quotation gives only the diameter, ask for the rest \u2014 a wheel without a full spec line cannot be checked against your vehicle.<\/p>\n

\"Ten-spoke
A forged alloy wheel face: five lug holes set the PCD, the large machined hole in the middle is the center bore.<\/figcaption><\/figure>\n

PCD: the pattern that decides whether it bolts on<\/h2>\n

PCD (pitch circle diameter) is written as two numbers. In 5×112<\/strong>, the first is the stud count and the second is the diameter of the invisible circle their centers sit on, in millimetres. Four- and five-stud patterns dominate passenger cars, six-stud patterns are common on off-road trucks, and eight-stud patterns appear on heavy trucks and buses \u2014 see our truck & bus wheels<\/a>.<\/p>\n

Patterns commonly quoted include 4×100, 4×108, 5×108, 5×112, 5×114.3, 5×120, 5×127, 6×139.7 and 8×165.1. One pair deserves care: 5×112 and 5×114.3 differ by only 2.3 mm<\/strong> on the stud circle. Lug holes can appear to line up and the nuts may even start threading, but the wheel never seats concentrically \u2014 it will vibrate and eventually damage the studs. Never substitute one for the other.<\/p>\n

Measure the hub, not the brochure<\/h3>\n

Vehicle databases are organized by model families, and regional variants can carry different PCDs. On a four-stud<\/strong> hub, measure center-to-center across opposite studs \u2014 that distance is the PCD. On a five-stud<\/strong> hub there is no opposite stud, so measure two adjacent studs and convert with a PCD chart. Confirm the thread pitch too \u2014 M12x1.5, M14x1.25 and M14x1.5 are common \u2014 since the hardware must match both hub and wheel seat.<\/p>\n

Offset (ET): what pushes the wheel in or out<\/h2>\n

Offset is the distance in millimetres between the wheel’s hub mounting pad and its true centerline. Positive ET<\/strong> puts the pad outboard of the centerline, so the wheel tucks inward toward the suspension \u2014 most modern passenger fitments run ET30\u2013ET45. Zero ET<\/strong> puts the pad on the centerline. Negative ET<\/strong> puts it inboard, so the wheel pushes outward, which is the look most deep-dish off-road and classic builds use.<\/p>\n

Every 5 mm of offset change moves the outer face roughly 5 mm in or out, with the inner barrel moving the opposite way \u2014 which is why a set that looked fine on a display car can rub a strut or brake line on yours. The commonly quoted rule of thumb for width: adding about 10 mm of rim width at the same offset moves the inner edge roughly 5 mm inward and the outer edge roughly 5 mm outward.<\/p>\n

\"Off-road
A deep-lip off-road beadlock wheel \u2014 the negative-offset profile pushes the face outward for track width and clearance.<\/figcaption><\/figure>\n

How to check offset before you order<\/h3>\n
    \n
  1. Find the stock ET stamped on the back of your current wheels.<\/li>\n
  2. Note your clearance \u2014 or lack of it \u2014 at full lock and full compression.<\/li>\n
  3. Ask for a wheel drawing<\/strong> showing diameter, width, ET and barrel profile \u2014 our forged wheels<\/a> are machined to order, so the drawing is confirmed before production.<\/li>\n<\/ol>\n

    Center bore: the number that decides whether it shakes<\/h2>\n

    The center bore is the large machined hole in the middle of the wheel. When it matches the hub’s raised pilot, the wheel is hub-centric<\/strong> \u2014 the hub carries the load and the lug bolts only clamp. When the bore is larger, the wheel is lug-centric<\/strong> and centering depends entirely on the lugs, which is why unevenly torqued hardware shows up as vibration.<\/p>\n

    The fix for an oversized bore is a spigot (hub centric) ring<\/strong> that fills the gap:<\/p>\n