Wheel and Tyre Fitment: Lug Patterns
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Lug Patterns
04.17
| 00:00 | The lug pattern, also referred to as the bolt or stud pattern, describes the arrangement of the holes for mounting the wheel to the hub and naturally the corresponding features on the hub. |
| 00:12 | This goes for centre lock wheels as well as the drive pins will be spaced equally on a PCD. |
| 00:19 | These are somewhat of a rarity though and the lug mounted wheels are much more common, so these will be our focus. |
| 00:26 | During our earlier discussions around the different methods of mounting wheels, we briefly covered the meaning of PCD, which stands for pitch circle diameter. |
| 00:36 | Sometimes this term is used to refer to the lug pattern but this is really just the diameter of the imaginary circle that the lug holes of the wheel are equally spaced around. |
| 00:46 | This is typically between about 100-120mm for smaller vehicles and anywhere up to about 180mm or so for heavier duty SUVs and pickups. |
| 00:58 | Anything bigger than this isn't really of interest to us. |
| 01:01 | The other important number next to the PCD is the number of holes. |
| 01:05 | And this is typically 4 or 5 for most performance cars and 6 or 8 for SUVs and pickups. |
| 01:12 | So, lug patterns are usually expressed as the number of holes multiplied by the PCD. |
| 01:18 | For example, 4x100 is a typical pattern for small Hondas and means that there are 4 holes equally spaced on a 100mm circle. |
| 01:28 | Another common pattern is 5x114.3, which might be the most common lug pattern used in the industry and describes 5 holes equally spaced on a circle of 114.3mm , which is actually 4.5 inches. |
| 01:46 | Unfortunately, while it would be nice, there's no industry wide standard pattern. |
| 01:51 | In fact, different patterns aren't just used by different manufacturers, but by the same manufacturers on different models and even different trim levels of the same model. |
| 02:02 | If you don't know your lug pattern, it's usually very easy to find online, but we'll also be covering how to measure it later in the course. |
| 02:10 | Hopefully it's obvious that a wheel for one lug pattern won't bolt up to a hub with another. |
| 02:16 | Even if they are close enough that the wheel will slide on, torquing the nuts and bolts up will stress the studs or bolts and in the worst case, lead to a failure that could be extremely dangerous or at best result in some serious vibrations. |
| 02:31 | Multi fit wheels are available with two different PCDs. |
| 02:34 | This is done by the manufacturers to lower the production cost, as they'll be able to offer the wheel that fits more vehicles. |
| 02:41 | The effect on aesthetics and strength can be argued, but it clearly isn't ideal. |
| 02:47 | These shouldn't be mistaken for wheels with extra holes around the hub in the interest of weight reduction. |
| 02:53 | Like how a centre lock adapter can be used to convert lug style mounting to a centre lock, there are also adapters for converting one lug pattern to another, say 4x100 to 5x114.3 for example. |
| 03:07 | This part is bolted to the hub with hardware that sits below the mounting surface for the wheel and will have studs for the alternative lug pattern, spaced in between the original holes. |
| 03:18 | In some cases the wheels will have pockets that provide clearance to the end of the original studs, otherwise they'll need to be short enough to stay under the mounting surface. |
| 03:29 | These will space the wheels out 20mm or so, essentially changing the offset of the wheel and therefore the scrub radius and track width, all of which we'll be covering in more detail soon. |
| 03:41 | Adapters are used in motorsport with success but they're not the ideal solution, being a potential failure point and adding unsprung mass. |
| 03:49 | It's also important to note that adapters may or may not be legal for road use in your part of the world or in your race series, so be sure to check before purchasing wheels and adapters. |
| 04:01 | The key thing to remember is lug patterns are expressed in the number of holes in the PCD, and a wheel with one lug pattern won't fit a hub with another. |
| 04:10 | Adapters can be used but they aren't the ideal solution. |
