Posted by Warren Clarke Know How
For your vehicle to run smoothly, numerous car parts have to work together in harmony. One such part is the lug nut. This small, humble component plays a big role in helping your vehicle perform as it should.
So, what is a lug nut, and what does it do for you?
What Is a Lug Nut?A lug nut is a fastener that’s used on the wheel of your car to hold it securely in place. You’ll find lug nuts on everything from cars to vans to trucks; this type of wheel fastener is used on almost all large vehicles with rubber tires.
Most lug nuts are made of chrome-plated steel. The chrome plating that covers these lug nuts is designed to resist corrosion. Lighter lug nuts are also available for those who want to minimize vehicle weight for performance or efficiency reasons. These are typically made of titanium or anodized aluminum.
Essentially lug nuts are what keep your car’s wheels securely fastened to the vehicle. They do so by screwing onto the wheel studs, threaded rods that are fixed to each wheel hub, which are, in turn, fixed to the axles.
Each lug nut usually nestles into a recessed hole in the wheel, gripping the stud to hold the wheel firmly in place. Most modern cars have five studs and five lug nuts per wheel, but you may see some vehicles with just four, or heavy-duty vehicles with eight or more per wheel.
Types of Lug NutsLug nuts come in many different shapes and sizes. The size and model needed are typically dependent on the car model and the axle that it uses. When deciding which lug nut seat is best for the task, you’ll also need to consider the wheel itself.
Some varieties you might see include:
Lug nuts and lug bolts serve the same purpose: Both are designed to hold a vehicle’s wheels securely in place.
However, they differ in their design and in the way they attach to a vehicle. A lug bolt is essentially a threaded stem affixed to a head that fits into the socket of a wrench. Think of it as a large screw, or a wheel stud and a lug nut combined into one piece. While a lug nut threads onto a wheel stud that’s (semi-permanently) affixed to the wheel hub, a lug bolt fastens the brake rotor and wheel directly into holes in the wheel hub.
You’ll typically find lug bolts on vehicles made by European brands such as BMW, Audi and Volkswagen.
Which Type of Lug Nut Is Best for My Car?Your vehicle’s year, make and model are good places to start when identifying the best lug nut for your car. However, you’ll also need to consider the type of wheels the vehicle uses.
Keep these factors in mind when selecting lug nuts:
The best tool for loosening and tightening lug nuts is a torque wrench.
These tools come in analog and digital varieties, and anyone who dabbles in automotive work should consider keeping one in their garage. Always be sure to tighten to the proper torque specifications outlined by the manufacturer in your vehicle’s owner’s manual.
The bottom line is that lug nuts are what keep your car’s wheels securely fastened, and you rolling down the road smoothly — if one ever goes missing don’t wait to replace it!
Check out all the lug nuts and accessories available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on lug nuts, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
Photo courtesy of Wikimedia Commons.
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bolt, hardware, lug bolts, lug nut, lug nuts, nut, rims, wheels
I'm a writer and editor who's a regular contributor with the New York Daily News and Carfax, and my content has appeared in over 20 publications.
I've written content that covers industries such as automotive, medical, insurance, healthcare, real estate, plumbing, pest control, dental and hospitality.
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Most cars have five lug nuts per wheel. The term lug nut refers to the nut you twist to tighten or loosen the wheel, while the term “lug bolt” refers to the piece itself. Most wheels manufactured today have a lug bolt pattern of either 4×4.25″ or 5×4.5″. Lug bolts are measured from the center of one stud to the center of another stud that is directly across from it on a circle with a diameter (or radius) of 4.25” for four-bolt wheels and 4.5” for five-bolt wheels (hence, “4×4.25″ and “5×4.5″).
Since four- and five-lug patterns are common, most rims are designed with one or both in mind. However, if your vehicle came equipped with an unusual number of lugs—say, six instead of five—replacing your wheels will likely require special adapters to make them fit securely around your hub and axles
The number of lug nuts on a standard car wheel differs from one vehicle to the next.
While many cars require four lug nuts, some wheels accept five or more. The more lug nuts your wheel has, the more difficult it is for thieves to steal your tires and rims.
It’s important to note that not all cars have the same lug nut size or shape. For instance, certain vehicles feature “tuner” lugs, which are designed for cars with a high performance suspension system. If you want the best possible fit for your machine, check with an auto parts dealer or look online to see if there’s something specifically designed for your ride. You’ll need to know which type of thread you have (metric/standard), as well as how long each nut needs to be; these specifications can usually be found in an owner’s manual or service guidebook.
Also take note that most new vehicles are equipped with a torque-sensing differential so any variations in traction will result in the power being delivered evenly across all four wheels without spinning out on one side; this will help keep drivers safe while driving their cars through adverse conditions such as snowstorms!
Before you start shopping for lug nuts, you need to take a look at the lugs that are already on your vehicle.
More specifically, you need to determine what size they are. The size and shape of wheel lugs vary depending on the make and model of your car, so it’s important that you find replacements that match.
Using wheel lugs that are too small can be dangerous. Your wheels may fall off or become loose if the lug nuts don’t fit snugly. Larger ones can cause damage to your bolts or rims, and also run the risk of being over-torqued or stripped from your wheels altogether.
To prevent these problems from occurring, always double-check the size of your lugs before purchasing new ones. This is especially true if you’re swapping out old steel lug nuts for new aluminum alloy ones—the original nuts may not have been rated for more torque than the new ones require!.
Now that you know how to check your lug nuts for thread size and pitch, you should confirm the thread of your wheel studs. If they are different from your lug nuts, you need a new set of wheels.
You may be surprised to learn just how many different kinds of lug nuts there are available on the market. Some of them have a knurled surface, to help prevent loosening from vibration over time. Others have tapered ends; these are usually used for racing cars and other high-speed applications where the impact of rocks or other debris can cause damage if there is too much metal exposed. The most common type has an open-end design and is constructed out of steel with some form of coating overtop such as chrome plating or painted colors like red, black or blue.
There are five lug nuts per wheel on most cars. The number of lug nuts is important because the more lug nuts you have, the more bolts there are to keep the wheels attached to your car. It might seem like adding extra lug nuts would make your car safer, but this is not true—as we’ll discuss in a moment, having too many lug nuts can actually be dangerous.
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While most cars have five lug nuts per wheel, you can add extra ones if you’re concerned about safety. However, it’s only safe to do this with trailer wheels—if you’re driving a standard vehicle and want to add extra lug nuts for safety reasons, you should talk to an auto manufacturer or mechanic before doing so. Car wheels tend to have different spacing for the studs that hold the tires in place and therefore require all five of their standard lug nuts in order to work properly. Using fewer than five can also be unsafe; this may seem obvious since it would leave your tire more vulnerable than usual, but it could also cause your car’s safety systems (like ABS) not to function correctly if they were designed while assuming that five lug nuts were being used on each wheel.
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Why are small diameter wheels still used in Formula 1? What are the benefits of switching to low profile tyres? What parts does the wheel hub consist of, and how can you secure the wheel with a single nut? Marussia F1 technical consultant Pat Symonds answered these questions and more in the next issue of British F1 Racing.
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century, when teams began to experiment with larger diameter wheels, and the FIA decided to introduce restrictions, considering such research as an extra waste of money.Later, the teams themselves refused to make any adjustments, since this would require a revision of almost the entire design of the car.0005
On the one hand, the small diameter of the wheels complicates the work on the machine, on the other hand, it makes it easier in a number of aspects. With such a high sidewall, almost 50% of the damping effect is directly on the tires, which makes the suspension geometry not as important as it would be in the case of low profile tires, for which the extreme stiffness of the sidewalls requires a clear positioning of the tires on the track surface and, therefore, a more sophisticated design. suspension arms. Again, a larger wheel diameter would make it easier to place the brakes, and the teams would have the opportunity to use larger brakes with a longer resource - although in this case the FIA would have to first fix this possibility in the technical regulations.
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What are the benefits of switching to larger wheels with low profile tires, you ask? Larger wheels would not only give the machines a more modern look, they would make it much easier for engineers to place wheel hubs there. In addition, this would seriously affect the principle of operation of the tires and the efficiency of their heating.
Racers often talk about getting their tires up to temperature. You might think that we are talking about the thermal energy released in the process of rubbing the tire on the track surface. This is partly true, but in this case only the outer surface of the tire heats up. However, rubber is a fairly good conductor of heat, and it gradually spreads to the tire carcass, which must also be heated to the required temperature. nine0005
But the warming up of the carcass itself is achieved to a greater extent due to tire deformation. Squash players know that in order to make the ball more pliable, it is necessary to hit it several times, thereby raising its temperature.
It works similarly with tires: deformation occurs, firstly, due to the rolling of the wheel along the track, when the lower part of the tire forms the so-called contact patch; and secondly, due to the bending of the sidewalls of the tire during cornering. If the tires were low profile, they would deform much less and heat up less, which would require a completely different range of compounds - however, this is not so difficult to achieve. nine0005
Low profile tires are less pressure demanding. This is due to two factors: firstly, a more rigid frame needs less air support, and secondly, the air volume itself is smaller, and pressure does not change so significantly with temperature changes. Thus, low profile tires would be easier to use without any warm-up than the current high profile tires.
Let's move on from tires to wheel hubs. The hub consists of an axle and bearings inserted into a special housing. Regulations require that the hull be made of relatively common aluminum alloys capable of maintaining strength and rigidity at high temperatures.
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In previous years, hub shells were first made of magnesium alloys, which, however, did not have the best rigidity, then steel, and even later, machined titanium and more expensive lithium-aluminum and other sophisticated alloys. The current restrictions on the use of such materials is one of the measures aimed at preventing the increase in costs in Formula 1.
In the "bearing-axle" connection, the axle itself, made of titanium or high-strength alloy steel, rotates. A splined cone is fixed on the axle, to which a carbon brake disc is attached - through this cone, the braking force is transmitted to the axle. At the end of the axle there is a special thread onto which the wheel nut is screwed. The wheels are driven through special pins, which can either be attached to the axle and fit into special holes in the wheel, or vice versa - be attached to the wheel itself and fit into the holes in the axle. nine0005
The wheel mounting system is very sophisticated.
When the pit stop is given a little more than two seconds, everything should work flawlessly, and the design should not allow even the slightest mistakes to be made. This means that the wheel must immediately sit on the axle, and the wheel nut must be tightened the first time. The latest trend is to fasten the nut directly to the wheel, since in this case it is more likely to be installed correctly and there is less risk of thread stripping.
The thread itself has a diameter of 75 mm and has been carefully machined for better retention. Modern wheel nuts are not hexagonal, but toothed: when fastened, these teeth are inserted into special grooves in the wrench. nine0005
Finally, the wheel mounting system has special devices to prevent the wheel from slipping off the axle if the nut is lost. As we have already seen, they do not always work as required.
Is it possible to say that the wheel is the only area of the machine whose design is not determined by the requirements of aerodynamics? Not really.
Along with stiffness, which remains a key design parameter, the issue of airflow management in this area remains extremely important. Wishbones, linkages and pushrods are positioned so that aerodynamicists have the opportunity to accommodate all those numerous openings that we often see on brake air ducts. nine0005
The flow inside the wheel is also important, since it affects not only the cooling of the mechanisms, but also the redistribution of heat. Sometimes it is required to use the hot air coming from the brakes to heat the rims and, as a result, the tires. Well, if the rubber, on the contrary, overheats, a stream of cold air can be supplied to the disks. In general, which way the flow moves through the wheel can have a significant effect on the aerodynamic efficiency of this entire area.
A few years ago, before the ban came into force, all cars were equipped with fixed hub caps, which allowed air to exit the wheel at the optimum location. Nowadays, such technologies are again relevant - in particular, Red Bull Racing and Williams have spent a lot of effort on optimizing the flow in this area.
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It is often asked if Formula 1 uses the same wheel bearings as road cars. I answer - no. In road vehicles, bearings must comply with the parameters of mass models of axles and bushings. They are also required to pass up to 160 thousand kilometers without repair, and, moreover, their cost should be moderate. Formula 1 cars use larger diameter bearings to give the entire structure maximum rigidity.
At the same time, friction should be minimal: for these purposes, instead of steel balls, ceramic ones are used in the bearing. The balls are separated by special spacers, set in such a way that the bearings have sufficient preload, but do not show play at high temperatures. Each bearing costs £1,300 and there are eight on the car! nine0005
Finally, what materials are the wheels made of? Made of magnesium alloy, providing sufficient rigidity at high temperatures. Teams would prefer to use carbon fiber in order to reduce unsprung weight, increase stiffness and reduce inertia, but the rules do not allow them to do this.
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Example of marking parsing: 205/55 R16 94H XL
205 tire profile width in millimeters.
55 - the height of the tire profile as a percentage of its width. In our case: 55% of 205 mm = 112.75 mm.
Tire profile is a relative value and it is important to consider this when choosing rubber. If you want to use 215/55 R16 tires instead of 205/55 R16, then not only the width of the tire will increase, but also the height. This is only permissible if both of these dimensions are specified in the vehicle's instruction manual. nine0055 Low profile is considered to be a profile less than 45.
If this ratio is not specified (for example, 185/R14C), then it is equal to 80-82%, and the tire is called full profile.
Reinforced tires with this marking are usually used on minibuses and light trucks, where a large maximum wheel load is important.
R - indicates the radial design of the tire, according to the location of the carcass cords. It's not a radius. Formerly there were bias tires D , but now it is practically not manufactured.
16 - wheel (disk) diameter in inches. This is the "landing" diameter of the tire on the disk, it is also the inner size of the tire or the outer size of the disk.
94 - load index, the index of the permissible load capacity of the tire in our case is 670 kg. Load index table.
This is the limit load per wheel. For passenger cars, it is usually done with a margin and is not decisive when choosing tires. The load index is very important for minibuses and small trucks. To calculate the maximum allowable weight of the machine, multiply the maximum load weight per wheel by the number of wheels.
On the wheel itself, you can find the inscription Max Load, which will tell you the permissible load on one tire. Values are in kilograms (kg) and pounds (lbs), 1 lb = 0.4536 kg. nine0005
H - tire speed index, in our case 210 km / h. The larger it is, the faster you can ride on this tire. With this parameter, the tire manufacturer guarantees the normal operation of the rubber while constantly driving at the specified speed for several hours.
XL is a reinforced tire with a load index that is 3 units higher than conventional tires of the same size.
for example LT33X10.50 R15 114S
33 is the outside diameter of the tire in inches.
X - separator, does not carry a semantic load.
10.5 is the tire section width in inches.
R - indicates the radial structure of the tire.
15 - bore in inches. In the past, there were tires on the market from the American market, in which the diameter could be expressed as a fractional number, for example, 17.5. nine0005
Speed (S) and load (114) indexes for inch sizes are the same as for metric European sizes.
Marking contains information about the month and year of manufacture of the tire. These are four numbers in an oval on the side of the tire. The first two digits are the serial number of the week in the year, the second is the year. For example, 0519 indicates that the tire was released in 2019, on the 5th week of the year. Do not be afraid if at the time of purchase of the tire 2-3 years have passed from the date of production, subject to proper storage. nine0005
It shows how badly the tire is worn and therefore whether it is time to replace it. Usually located at the bottom of the groove located as close as possible to the inscription TWID (sometimes the inscriptions TWI , DSI are used).
An arrow indicates its location, making it easier to find.
Studded tires are marked as follows:
The red dot or triangle is placed at the hardest point on the tire sidewall. When installing a tire on an alloy wheel, this point must be aligned with the L mark on the wheel. nine0055 White dot or triangle is placed on the most flexible place on the sidewall. When installing rubber on an alloy wheel, this place should be diametrically opposed to the L mark. The yellow mark indicates the lightest place, which must be aligned with the place where the spool is installed on the disc.
Sometimes you can see colored lines applied to the tread of a new tire. They are factory markings that help warehouse workers keep tires with certain specifications in one place. On the other hand, in the presence of such stripes, the consumer can be sure that the tire has not yet been in use. nine0005
Tire manufacturers use different technologies to protect against cuts and punctures.
| Manufacturer | Marking |
| Bridgestone | RFT (Run-Flat Tire) |
| Continental | SSR (Self Supporting Run-Flat) |
| Goodyear | EMT (Extended Mobility Technology) or RunOnFlat |
| Kumho | RF |
| Michelin | ZP (Zero Pressure) |
| Pirelli | EUFORI@ or RF |
| Nokian | Run Flat or RF |
| Yokohama | RF |
These technologies allow the vehicle to continue moving through a pressure loss of 50 to 150 kilometers at speeds up to 80 km/h.
In addition, there is a marking indicating the presence or absence of some additional features. Specifically:
Tire pressure is indicated in PSI or kPa. PSI (pound-force per square inch) is a pound per square inch, a US unit of pressure. On tires, you can meet values in one and the other units at the same time. If only one value is indicated on the tire, then remember that 1 kgf / cm2 (technical atmosphere) \u003d 0.98 bar = 14.223 PSI = 98.066 kPa. On tires for special equipment, most often, you can see the value of "mounting pressure". It means the permissible pressure when mounting the tire on the rim, after mounting the tire can be inflated to operating pressure.
Unlike the M+S marking, the 3PMSF mark is only applied if the tire meets the Snow Performance Index. The grip coefficient of a tire on snowy road surfaces is calculated from three main parameters obtained from road tests. Grip reliability tests are carried out during braking on snow and during acceleration, as well as during acceleration during cornering. nine0151 When marking tires, manufacturers sometimes indicate additional information about the qualities and characteristics of products:
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| Load index | Permissible load, kg | Load index | Permissible load, kg |
| 0 | 45 | 140 | 2500 |
| 1 | 46. 2 | 141 | 2575 |
| 2 | 47.5 | 142 | 2650 |
| 3 | 48.7 | 143 | 2725 |
| 4 | 50 | 144 | 2800 |
| 5 | 51.5 | 145 | 2900 |
| 6 | 53 | 146 | 3000 |
| 7 | 54.5 | 147 | 3075 |
| 8 | 56 | 148 | 3150 |
| 9 | 58 | 149 | 3250 |
| 10 | 60 | 150 | 3350 |
| 11 | 61.5 | 151 | 3450 9019four |
| 12 | 63 | 152 | 3550 |
| 13 | 65 | 153 | 3650 |
| 14 | 67 | 154 | 3750 |
| 15 | 69 | 155 | 3875 |
| 16 | 71 | 156 9019four | 4000 |
| 17 | 73 | 157 | 4125 |
| 18 | 75 | 158 | 4250 |
| 19 | 77.  |
