Open letter to the SEMA, Wheel & Tire Council

Regarding the ET Lug Nut issue, “you’re welcome”. I realize I’m retired and therefore have a lot of extra time (so one would think). However, I grew up back in the days, when someone did something for another, especially without compensation, it deserved a “thank you”. Therefore I decided to take the first step (which is normally the second step) and give the proper response to a “thank you” with a “you’re welcome”.

The ET Lug Nut issue was another reason I believe that the Aftermarket Wheel Industry is in sad need of some technical people that know and understand what an automotive wheel is and what it is supposed to do. After reading some of the comments and lack of comments on your Basecamp email, regarding this issue, it confirmed my belief that there isn’t currently any competent technical people on your Council, and certainly no good knowledgeable people active in the industry today. I think there are a couple of folks that I used to consider very good technical guys, but they have since succumb to the ego feeding frenzy that seems to get to all of us a one point.

I’m sad to say that gone are the old timers that started this industry. Guys that were “Car Guys”, and actually worked in the industry, designing, developing new methods of making wheels and putting them together. Creating new finishes, new ways to attach the wheels to the vehicle and developing sales and marketing strategies to sell the wheels. Now is seems that the technical people are gone, replaced by a computer in China. Wheel engineers are really only a Chinaman on a computer running a SolidWorks or Pro-E CAD program. Structural knowledge and design is done by inputting the design into a Finite Element Analysis (FEA) computer program and letting it make the decisions. Not a bad way to do it if you don’t care about the weight of the wheel. In fact, I’d say the only folks that benefit from design by FEA are the aluminum companies and the shipping companies. The heavier the wheel, the happier they are.

Testing is a joke. All the Asian wheel companies have testing equipment and claim that their wheels are all tested and meet a standard. Based on my experience with Chinese companies (and there are many) they don’t understand the first thing about wheels much less how to test them. Remember, most of the factories have only been doing this for less than 10 years. Their technical people are all graduates of their universities, but most of them have never even driven a car, much less know anything about them. I doubt their universities have courses in wheel design, wheel testing or anything involving an automotive wheel. Their knowledge and experience is based on “monkey see, monkey do”, and what they’ve seen on the internet. I do believe they have classes in “how to copy anything, and make it cheaper”.

Other than technical people, the industry is flush with sales and marketing people. The day of the outside salesman is fast becoming extinct, because the internet is the now place to sell. Web sites are the new ego race. It is evident that the comments by some of the members of the ET Lug Nut) Task Group was proof that they had no clue about the purpose or history of the ET Lug Nut. A few buzz words like “shear point” and “torque value” would make one think they had some knowledge or technical background. By the way, what is “torque value”? Sounds very technical, so I would like to know what it means.

As for Fitments and Applications, that’s a bigger joke than testing. There are now a few companies that are offering fitment and application information for those companies that don’t have their own staff that goes out and actually checks brake caliper configurations, hub sizes, bolt patterns, offsets and fender clearances. I’ve seen some of this information and have seen a phrase or term that is called the “X Factor”. I’ve been told that that is the brake caliper clearance or condition that is used to determine the configuration of the back side of a wheel in order to assure there is no interference between the wheel and the brake system. I’ve designed a lot of wheels and can say from experience that to insure proper and ample brake clearance, I had to actually measure and chart the true configuration of the brake caliper in relation to the mounting surface of the wheel. I’m guessing that the “X Factor” is based on 3 conditions:

1) the brakes are really big.
2) the brakes aren’t that big.
3) the brakes aren’t big at all.

Designing wheels is an exact science, and the “X Factor” is just a way of saying, “we really don’t have any exact measurements or configurations, but we think it is —–”. As I said, a joke. But the industry seems to have bought it. I guess that speaks volumes for the industry as a hole today.

I’m sure all the members of the Select Committee are extremely busy these days due to the massive amount of business that is coming your way via the results of the Stimulus Plan that our new Leader and his Merry Band of Legislators have provided us. Oh wait a minute, maybe the Aftermarket Wheel Industry doesn’t get any of the Pork, because they haven’t shown enough failure or don’t have enough Union workers. In any event, when any of the Select Committee, SEMA Staff, ET Lug Nut) Task Group or any other member of the Wheel Industry finds time to thank me for my effort in helping resolve the ET Lug Nut controversy it would be appreciated. I’m excluding the one individual who responded to my TECH Stuff # 13 article in my blog, Brian Boley. He had some useful input the industry could benefit from. Thanks Brian.

13 Responses to “Open letter to the SEMA, Wheel & Tire Council”

  1. Fred Says:

    In regards to the fitments and applications, is X the clearance from the brake caliper to the wheel? if this is an unknown , what would be a safe clearance (2mm?) or is there a min standard for clearance? I’m interested is there a min industry standard ?

  2. Larry Says:

    Yes the so-called “X Factor” is the clearance between the wheel and the brake system. And no, there is no industry standard.
    When I was applying for a TUV (the German regulatory agency)certification, I was informed that they required a 2mm clearance from the wheel to any part of the braking or suspension systems. I adopted that as my standard when I designed wheels.
    Great question, I wish more people were interested in that type information.

  3. scott Says:

    X factor is the horizontal measurement in mm from the mounting flange to the outer most point of the caliper/bracket.

    Y factor is the same measurement from the centerline vertically

  4. Fred Says:

    I have another question regarding offset, I’ve been searching for a nicer wheel for my 2010 Tundra because the factory wheel looks too plain. In my search I’ve noticed that most after market wheels for the Tundra have a 30mm to 35mm offset . The OEM wheel is at 60mm. OEM spec is 20×8 @ 60mm my current wheel the wheels I’ve seen after market are 20×9 @ 30mm or 35mm. My question is why would the aftermarket wheel be so different? What should I be concerned with? It seems like they sell a lot of these wheels, does the aftermarket have a base line spec they start with?

  5. Larry Says:

    Thanks for your reply. It appears that you are a working member of the wheel industry. I’m happy to see that folks like you are reading my ramblings.
    I’m going to assume that you are in the engineering/design end of the business and have access to a CAD system that would allow you to open a DXF drawing I’m emailing you. This drawing is a simple layout of the vertical and horizontal lines of a wheel showing the centerline and the mounting face. I have included 4 actual brake caliper profiles that I have acquired using my method of measuring these profiles. They are all of passenger cars ranging in years from the early 90′s to the mid 2000′s. I have designed wheels that will accommodate all four of these brakes in one wheel. I tried to use the X and Y factors you described and was unable to develop a configuration using only the X & Y of each brake that would work on all 4 vehicles. I can only assume that I am doing something different than the designers that are using the X & Y Factors. If you can download my drawing and use the brake profiles that I show, and create a configuration that will work in one wheel to fit all 4 vehicles, then I will concede that the X & Y Factors are a viable method. Thanks again for your interest.

  6. Kimberly Lewis Says:

    I got your name from Ken Archibald as having some knowledge about the aluminum wheel manufacturing industry in the 1970-1980′s. Pleas call me at 310 281 6332. Thanks.

  7. Martin Says:

    I don’t know much about wheels. I think older classic cars look far better with some deep chrome Cragers than the stupid 22 inch spinners. I would think they handle and ride better also. I would like a site where women contact me and say I have knowledge in so and so and to call them as Kimberly asks lol

  8. Larry Says:


    I agree about the look of 22′s on a classic car, unless the owner is an NBA basketball player. As for the women contacting me; ah, if it were only as you made it sound.

    Thanks for the laugh,

  9. snmiedo Says:


    Congratulations on your retirement! I came across your BLOG when I was surfing the web. Would really like to speak to you for some advice if possible. My e-mail is if you would have a few minutes to talk.

    By the way, nice ride in the photos section.

    Again, congtratulations on a great career.

    Best regards,
    Mike Cohen
    Racer X Motorsports, Inc.

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