Archive for the 'TECH Stuff' Category

TECH Stuff # 13 – ET Lug Nuts. What are they, and why?

Friday, February 20th, 2009

Within the Aftermarket Wheel Industry, a controversy began during a meeting of the Wheel & Tire Industry Council meeting at the 2008 SEMA Show. A presentation was being done by some of the members regarding Fitments and Applications. It was suggested that ET lug nuts are recommended in cases where questionable thread engagement was present. A statement came from the audience, that ET lug nuts did nothing for thread engagement and had no usable purpose. I took exception to that statement and argued that ET lug nuts are all about thread engagement. Since that meeting there has been a lot of discussion in regards to the true purpose of ET lug nuts, why they were developed and a lot of other hog wash about technical aspects of lug nuts in general. I’d like to add my 2 cents to this discussion. I’ll start by giving my recollection of why ET lug nuts were developed.

Going back to the 50′s and early 60′s, the Aftermarket Wheel Industry was born because of the desire of car guys that wanted something other than stock painted wheels in stock sizes. These cars guys wanted chrome wheels and they wanted them wider so they could use bigger tires. At that time, the OEM’s didn’t offer aluminum wheels. As a result the stud length was shorter on the vehicles. The average stud length was about 3/4″ to 7/8″. This was adequate for steel wheels and there were no thread engagement issues. Then in the early 60′s, the Aftermarket Wheel Industry started offering aluminum alloy wheels. The developers of these wheels solved the thread engagement problem by coming up with the Mag Type lug nut. Since the mounting pad thickness was about the same thickness as the stud length on the vehicles, which left little or no threads on the stud to attach a standard conical seat lug nut, they came up with a lug nut that had a shank that went into the wheel lug hole enough to accomplish proper thread engagement (see illustration). This system was adequate but left a lot to be desired. In order to assure that the wheel was attached to the vehicle with good alignment and acceptable runout, the diameter of the lug hole had to be drilled with a minimum of clearance for the lug nut. After the vehicle was driven enough to heat up the brakes and wheels, the aluminum wheel expanded, thus shrinking the diameter of the lug nut hole. It was then very difficult to remove the lug nuts when the wheel was hot, in order to change a flat tire or what ever.

Now moving forward in time, the OEM’s began offering aluminum alloy wheels on new vehicles. They determined that the use of Mag Type lug nuts was not the best system. They began to offer their aluminum wheels with conical seat lug nuts. They did however lengthen the studs on the vehicles that were offered with aluminum wheels so there was adequate thread engagement. This prompted the Aftermarket Industry to adjust their offering so they could keep up with the OEM’s. In the late 80′s, the Aftermarket Industry began drilling their lug holes with a conical seat instead of the Mag Type lug hole. It was then discovered that the use of a standard lug nut (Acorn Type) was causing problems with the seating area of the wheel. Steel inserts was a solution, but it was soon discovered that the OEM’s were using a Bulged Type lug nut which eliminated the problem with the seating area. So the Aftermarket lug nut manufacturers started offering Bulged Type lug nuts. At that point it seemed that all was well in the Aftermarket Wheel Industry. Not so.

The problem of thread engagement became an issue when a conversion from steel to alloy wheels was made on vehicles that had short studs and were never intended to have alloy wheels. The Aftermarket again responded by developing a Bulged Type lug nut with an extension that would go into the lug hole enough so that proper thread engagement could be accomplished. This lug nut was called the ET (extended thread). Combined with the bulged seat area, the extended thread provides the best attachment that is currently offered.

I have recently observed another problem. In my illustration I show examples of wheels with mounting pad thicknesses from .390″(10mm) to .630″(16mm). I do not recommend a mounting pad thickness to be greater than .390″(10mm). I have done extensive testing on wheels produced in China since 1993 using a .390″(10mm) mounting pad thickness. I have sold in excess of 750,000 wheels and never experienced any failures. Using a Std. Bulged Type lug nut in a wheel with a .390″(10mm) pad thickness on a vehicle with short studs (.800″) (see illustration) is still under the minimum thread engagement recommendation of SAE. And using an ET Bulged Type lug nut in a wheel with a .630″(16mm) pad thickness on a vehicle with short studs (.800″) (again see illustration) is also under the minimum thread engagement recommendation of SAE. In my opinion, ET lug nuts should be used on all aluminum wheels. In summary, what does an ET Type lug nut do? It provides a method to assure proper thread engagement. What is proper thread engagement? Proper thread engagement is defined as engaging the threads onto the bolt or stud by at least the diameter of the bolt or stud. Prior to mounting a wheel on a vehicle, the length of the stud should be checked against the thickness of the mounting pad below the bottom of the conical or spherical seat. Another way to check is to mount the wheel and check how many turns the fastener makes before it reaches the seating area. An example is if using a ½”-20 nut, then there should be at least 10 complete turns.

TECH Stuff #12 My Thoughts and Comments

Saturday, June 2nd, 2007

Since this is the last of a series of TECH Stuff added to the advertisement for the TQ, SLT and RT5 wheels, I decided to take the opportunity to put in a plug for the wheels and the company that offers them. They are great wheels. They are manufactured to the highest quality standards, tested to meet the SAE J2530 Aftermarket Wheel specification, and designed to offer the best sizes, fitments and styling for Hot Rods, Customs and Muscle Cars. I’m a bit partial because I designed and created them. I retired in January of 2007. (more…)

TECH Stuff #11 Modified Wheels – Safe or Risky?

Friday, June 1st, 2007

The original equipment wheels that the factory puts on cars and trucks are designed and tested for use on a specific vehicle.  The wheels that the aftermarket offers are designed and tested to fit a wide range of vehicles.  The range of those vehicles is determined primarily by the load rating or weight of the vehicles.  Both OEM and Aftermarket wheels are designed and tested to a standard and to a maximum load carrying capacity. In TECH Stuff 3, wheel standards, testing procedures, marking requirements and load ratings were discussed.  Using a wheel that was designed, tested and manufactured for a different vehicle carries some risks.  Modifying a wheel to fit a different vehicle than originally intended, carries even larger risks. (more…)

TECH Stuff #10 How to choose the wheels for your Rod

Tuesday, May 15th, 2007

Choosing the wheels you want to run on your Rod involves a few things to think about.  Style, finish and size are the main considerations, but before you make those choices, there are a few things to mull over.

1.  Style

I’m sure we all have a style in mind that we’ve pictured in our heads that would look cool on our Rod.  The 3 most significant appearance features of a custom ride are the body styling, the paint scheme and the custom wheels.  The wrong wheels on a custom rod is the same as wearing brown shoes with a tuxedo.  Some of us are nostalgia freaks that want the same custom wheels we had on our first car, and then there are those who think billet is cool and others who want a touch of today in their wheel style.  In any event, make sure the wheels you want are available for your particular Rod.

2.  Finish

In an earlier TECH Stuff (#7) we discussed finishes of custom wheels along with their proper care and maintenance.  This is a big consideration.  Painted and chrome wheels require the least maintenance.  Polished aluminum requires the most.  Think about how much time you are willing to or can devote to cleaning your wheels.  Also check out the finishes available for the style of wheel you want.  Steel wheels are available in painted or chrome.  Cast one piece aluminum and forged wheels are available in painted, machined finished, polished and all chrome.  Billet 2 piece wheels are offered in machined or polished only.  Composite (steel rim / aluminum center) only come in all chrome.

3.  Size

After you have made your style choice, check to see the available sizes.  The older styles that are still available are most likely offered in 14″ & 15″.  The newer styles are probably not available in 14″ and the pickens are slim in 15″.  For some reason a lot of the manufactures have skipped the 16″ and gone with 17″ and up.  I personally like the 16″ because the tire selection is huge and you still get the big meat look with the tires and the nostalgia look with the wheels.  The trend of big wheels and low profile tires is becoming more popular with the Rodders every year.  The steel wheel with baby moons and trim rings starts to look goofy in 17″ and the early composites and one piece aluminum styles get lost after 17″.  So if you’re into the nostalgia look of the 50′s, 60′s and 70′s, plan on sticking with 14″, 15″ and 16″ wheels. 

4. Other things to think about

A.  Does your Rod have or do you plan to convert to disc brakes?  Some of the aftermarket brake systems are not very wheel friendly.  Make sure you check with the brake manufacturer to verify the compatibility between his brakes and your wheels.  I think some of these brake manufacturers think everyone buys brakes first, then builds a Rod to fit them.  I’d bet there were more Rods built around a set of wheels than brakes.  I’ve never had a brake manufacturer call me and ask for wheel profiles or samples to check against their brakes.  Seems like the logical thing to do.

B.  Check the bolt pattern (TECH Stuff #2) on your Rod to make sure the wheels you want are available in your bolt pattern.  There are a lot of Mopar guys out there that have stressed out trying to find a 5×4.00″ bolt pattern in the wheel style of their choice.

C.  Make sure you have verified the load rating of your wheel choice to the load requirements of your Rod (TECH Stuff #3). 

D. Last but certainly not least, check your clearance in the wheel well.  Check for fender clearance, brake clearance, suspension and steering component interference.  Refer to TECH Stuff #1 for more information on determining your wheel backspacing or offset.  Nothing is more irritating than tire rub when turning or going over bumps. 

In summary, do your homework before you decide on your wheels.  They can make your Rod.  And remember, don’t go to the prom with brown shoes.

TECH Stuff #9 A few facts about using Nitrogen in tires

Tuesday, May 1st, 2007

Using Nitrogen to inflate tires instead of plain old air or oxygen is not a new phenomenon, but it sure is getting some attention lately.  I did some research on the subject and decided I was missing the boat.  I’m one of the 85% of Americans that don’t regularly check the inflation pressure in my tires (I wonder who took that survey?).  Based on my research, I should be using Nitrogen.  I learned that Nitrogen is all around us and we take in Nitrogen in every breath of air we breathe in. (more…)

TECH Stuff #8 the pro’s and con’s of Plus Sizing

Sunday, April 15th, 2007

Plus Sizing is a fairly recent trend (I think it started in the late 80′s or early 90′s). Well when I say recent, I mean compared to the 50′s and 60′s when I was getting into cars and making them street cool. The basic idea of Plus Sizing is to replace the stock wheel size with a larger diameter wheel and still maintain the same original tire and wheel combination diameter. Back in the early days, up to and including the 70′s, the only thing that happened when you put larger diameter tires on your rod, was the speedometer read slower than you were actually going. That only worked when you said but Dad, the speedometer said I was only going 50. (more…)

TECH Stuff #7 Proper Care of your wheels

Sunday, April 1st, 2007

There are several different types of finishes available for Aftermarket Wheels.  Most wheel companies offer a warranty on the finish.  In most cases, painted wheels have a 1 year warranty.  Most chrome wheels have a 2 year warranty, and in some cases a 3 year warranty.  Polished aluminum wheels are only warranteed until you take them out of the box.  In any event, the buyer has the responsibility to properly maintain the wheels.  There are a lot of folks out there that pay a lot of money for custom wheels then only clean them when they send the car through the car wash once in awhile.  It takes time and elbow grease to keep custom wheels clean and to protect the finish.  I’ve seen chrome wheels that customers wanted to return because they were pitted or rusting so bad that they look like the car was parked on the bottom of Lake Michigan for the winter.  If you don’t maintain your wheels, don’t expect the manufacturer to take them back and give you a new set.


TECH Stuff #6 the scoop on Adapters and Spacers

Thursday, March 15th, 2007

There are a lot of theories floating around about the use of wheel adapters and spacers and their safety.  Here are a few facts and thoughts that will help you make your decision whether to use them or not. (more…)

TECH Stuff #5 Types of aftermarket wheels

Thursday, March 1st, 2007

There are several types of construction that are used to make wheels for the aftermarket. The type of construction does not necessarily mean that one type is better than the other. Some types of construction allow for more elaborate styling or finishing, others reduce weight, while others are for the purpose of duplicating the original equipment wheels. In any case, the strength and safety aspects of the wheel are based on the design and manufacturing quality built in by the manufacturer. Remember, as discussed in TECH Stuff #3, all the wheels sold should be tested to a recognized specification or standard by the manufacturer to assure that they are safe and reliable regardless of what type construction they are. (more…)

TECH Stuff #4 a few facts about lug nuts

Thursday, February 15th, 2007

Here are a few facts about wheel fasteners you should know before you bolt up your wheels on your ride. (more…)