by Bob Beranek

I am frequently asked, “What is better, original equipment manufactured (OEM) auto glass or aftermarket auto glass (ARG)?” This question is not as easily answered as one may think. All glass installed in a motor vehicle must pass federal regulations for safety as described in Federal Motor Vehicle Safety Standard (FMVSS) 205 and more specifically in ANSI Z26.1. Though federal regulations demand certain safety requirements, all glass is not the same in fit, construction and appearance. Let us look at some of the differences.

First of all, we must define manufacturing and fabricating.

Manufacturing means the making of a product from raw materials. In the case of glass, a manufacturer takes silica sand, soda ash, limestone, dolomite and other additives and creates a product called annealed glass.

Fabricating is a process that takes the result of manufacturing (annealed glass) and creates a finished product to be used by the end user. In our case, that would be laminated windshields or tempered side parts.

Fabricating differences

The way auto glass is fabricated is the difference between perfectly fitting parts and not so perfectly fittings parts. Auto glass fabricating can be categorized under three headings, original equipment (OE), original equipment manufacturers (OEM), and aftermarket replacement glass (ARG). To understand auto glass quality, we must first understand what is meant by these categories.

         Original Equipment producers (OE)

When a vehicle manufacturer designs a vehicle for production, they select vendors to supply their assembly plants with the parts necessary to construct their vehicle. The vendors are selected based on price, technology capabilities, quality control processes and production capabilities. These vendors are called OE producers. The vehicle manufacturer then details, to the OE producer, the parts’ specifications for production. Once the part is produced, the vendor delivers the part to the assembly plant and/or to the vehicle manufacturer’s parts house for distribution.

       Original Equipment Manufacturers (OEM)

The difference between an original equipment manufacturer (OEM) and OE is that the OEM is an OE producer for some makes, but not necessarily for the particular vehicle being worked on.  For example, Carlite is the OE manufacturer of glass parts for Ford Motor Company vehicles, but they also make parts for the aftermarket installations on other brands of vehicles like GM.  Carlite is considered an OEM manufacturer because they are the OE supplier for Ford and meet the same quality control requirements of other OE suppliers. The only difference between an OE part and an OEM part is the way the manufacturer collects the specifications of the glass. The OE receives the specs from the vehicle manufacturer themselves and has the exact tolerances required by the design engineers, while the OEM must fabricate the specs from an obtained part.  The OEM has the quality control in place to produce a well-fitting part no matter how they collect data so OEM fabricators are considered high quality producers.

      Aftermarket Fabricators (ARG)

The aftermarket replacement glass (ARG) fabricators produce glass for all vehicles for aftermarket installation only. They are not considered OE or OEM manufacturers because they do not produce auto glass for vehicle manufacturers’ assembly plants. So, how does an ARG manufacturer obtain the specifications necessary to produce a well-fitting auto glass part? This is achieved by a process called reverse engineering. Reverse engineering is obtaining a part or vehicle from an independent distributor and then making measurements and patterns to construct their product. Neither vehicle manufacturers nor glass manufacturers will share the auto glass part specifications with the aftermarket producers, usually because of contractual obligations.  Therefore, reverse engineering is their only recourse. Considering that reverse engineering is dependent on the accuracy of the original part, and the quality control built into the fabrication process, the possibility of mis-fitting parts is always a concern.


Now that we understand the three labels used to describe fabricated auto glass parts, we can discuss the difference in each. I think that you can categorize this debate into a number of issues that are important to the customer, installer and/or shop owner.

  1. Safety
  2. Price
  3. Fit
  4. Performance


The safety built into the fabrication of the glass is controlled by the federal government and no glass company can deviate from that regulation and expect to sell auto glass in the U.S. What safety issues are regulated? It would take another entire article to explain the requirements put upon glass fabricators. But, to simplify it to is lowest common denominator, it is the safety characteristics of fractured tempered glass and the protection offered by the lamination between the two layers of annealed glass that make up the windshield. So, whether the glass is OEM or ARG, the safety constructed into the auto glass part is regulated by federal safety standards. But that is where the similarity ends.


The reason that there are aftermarket parts is for price competition. There is always a need for less expensive parts, whether that will be vinyl moldings that surround the glass edge, clips that retain the moldings or the glass part itself. How does an ARG fabricator produce less expensive glass parts? There could be a number of reasons, both positive and negative depending on your point of view, that the price can be less expensive for a similar part produced by the OEM.

  • Less quality control stations during production means less labor costs.
  • Materials purchased from off-shore suppliers means less material costs.
  • Elimination of value-added hardware means less production costs.
  • Inferior technology built into the part can mean less material and production costs.
  • More efficient manufacturing processes means less production and labor costs.
  • More efficient logistics means less shipping and delivery costs.



If you ask an auto glass technician the kind of glass he would like to install he will always say OEM. Why? Because it fits every time, there are fewer customer complaints and there are no surprises to be resolved. If you ask an owner what kind of glass he would like to buy, he will say the least expensive and the easiest to get. Why? Because profits are better than losses, speed of delivery is important to beat competition and the less expensive part is easier to sell to the insurance and retail customer. The shop owner is confident that his technician can deal with a slight misfit of the glass and usually he is right about that. Any good technician can make adjustments to mis-fitting parts, but it will take training and practice to become proficient, and the little fixes take more time and aggravation in order to complete the job to the customer’s satisfaction.


The most misunderstood issue when it comes to OEM v ARG is performance. The modern day glass part is a technological marvel with rain sensors, solar protection, hydrophobic capabilities and acoustical sound deadening. Many people involved with its replacement don’t even understand its importance to performance or protection. If asked, the customer will always request OEM glass until they’re told the price. Then they will consider other options. It is true that many performance-added items are not important to safety and if the customer does not want to pay the price of replacing those value-added items, they have a right to choose not to re-install them. However, some of the items built into the glass part are safety related, such as heads-up-display (HUD) or Pre-Applied Adhesive System (PAAS), and cannot be eliminated. While other performance features are misrepresented as the same, but are so inferior to the OE features that misrepresenting it as an equal to the OE could be a breach of professional ethics. An example of this is the solar-coated reflective part versus the solar absorbing part.

One example is the recent issue brought up by the Auto Glass Safety Council (formerly the AGRSS Council Inc.) concerning the misrepresentation of a Pre-Applied Adhesive System (PAAS) part sold by a distributor (FW2525). The OEM part uses a pre-applied bead of cured adhesive on which the new bonding adhesive is to be applied. The ARG part ordered came with no PAAS but was labeled as a PAAS part. The dilemma is that if it was installed without the visible PAAS trim, the customer’s vehicle would not appear to be the same aesthetically, though it could be installed safely. If the technician applied an underside molding to make it appear to look the same as OE, then the molding would hinder the safety of the bonding bead of adhesive. When the distributor was asked about the absence of the PAAS their response was, “I don’t know but we sell a lot of ‘em.” Does that mean that all those customers don’t care about their moldings being missing? Or, does it mean that the glass was installed improperly? We only hope it was the former.

Another safety issue is the paint band around the perimeter of the auto glass part called the frit.  Nowhere in the FMVSS 205 or in the ANSI Z26.1 is the frit mentioned, though it is one of the most important surfaces on the glass part. The frit is where the bonding adhesive is applied to the glass. If the frit paint is improperly applied, then the windshield will not serve the role of restraint for the occupants or the backstop for the airbag if so designed. The OEM glass fabricators know the importance of the frit and its application because they are privy to the specifications dictated by the engineers. We know that many ARG fabricators know the importance of the frit, but do all fabricators know this important role?

In summary, the modern day auto glass part is a technologically advanced product that must be installed perfectly by trained professionals to be a safe structural part of the vehicle’s protective cage. For all of the performance features to work perfectly and the fit to be aesthetically pleasing to the eye, the part must meet the specifications stated by the vehicle designers. The consumer who chooses the replacement glass for their vehicle should prioritize what is important to them when it comes to appearance, performance, value and safety. Then they can make the decision that is best for their particular needs.

Comments (20)

  1. Ben Flemk said on 08-06-2012

    Great informative article! I am a shop owner/installer. I know some of the oem manufacturers but which companies are considered arg?

    • Bob Beranek said on 21-06-2012

      Ben – the easy answer to your question is all the manufacturers/fabricators that do not supply the OE market. There are several off-shore companies and a few domestic.

  2. Richard Jutras said on 08-06-2012

    Congratulations ! First article I read in years which is objective and written without trying to put down anybody specifically. Can I have your permission to translate your article in french for the benefit of our customers.


    • Daniel said on 14-06-2012

      Allez la France !
      Or…a la votre, Quebec !

    • Bob Beranek said on 21-06-2012

      Richard – Though I wrote the article, the copyright is that of my publisher Key Communications. If you wish to contact them and ask permission, I personally have no problem with your request. I would like the byline though. I’m vain that way.

  3. Bob Hittenberger said on 08-06-2012

    Excellent article Bob. This is one of the best definitions and explanations of the differences between OE, OEM and ARG glass I’ve ever seen published.

  4. Daniel said on 11-06-2012

    Far from pretending to be among the best worldwide installer (not that I am not he-he-he), I dare to launch or enhance a basic issue: CUSTOMER EDUCATION.
    If the customer is taught about the pluses and the minuses of each choice (OE, OEM and ARG) for a certain requested item.
    Once the choice is made for the ARG, the customer must be informed about the EXTENDED working time due to the corrections and the extra fittings to be performed to push the installation quality as close as possible to the standards offered by using an OEM part. This extra time adds extra expenses with the labor and the final price might not prove so very attractive if cheap glass is chosen. In fact, working longer and harder without excellent results guaranteed, in conditions of limited profit margins might not stimulate the technician for an accurate, dedicated and state-of-the-art job.
    Sometimes, expertise and skill might prove not being enough to achieve the top standards, when using ARG, jeopardizing the trust and the image of the replacement provider.
    Once again: Inform your customer and lead him/her to the best choice that will fit your goals, that’s why you’re an Independent [Master] Autoglass Technician (IMAT) !

    • Daniel said on 11-06-2012


      @Paragraph #2:
      If the customer is taught about the pluses and the minuses of each choice (OM, OEM or ARG) for a certain requested item, then you multiply the chances of being well understood when proposing the choice that will assure a great job and a satisfied buyer.

  5. Glasseye said on 11-06-2012

    I agree that if customers were better informed about the various ways automotive glass is provided, it would help them in making their choice. However, in reality, the decision is largely who to use rather than what quality to use. Unless the customer clearly states they want an OEM replacment glass, the choice is left to the company they have contracted to replace the glass. This rule normally applies only to the windscreen (windshield), if it is a side or rear glass these would normally be refitted with OEM glass, since the incidence of replacement is too low for ARG suppliers to invest in manufacturing.

  6. Quinn said on 11-06-2012

    If anybody would know an answer to a question I have.

    Is it true that the same glass manufacturers who produce glass aftermarket are the ones who produce glass for the auto manufacturers (OEM)? I remember in the article it said that Carlite produces OE specified parts for for Ford – the OEM must fabricate the specs from an obtained part, this makes it OEM. I read that Ford is the only automotive company who produces their own glass parts because Carlite is owned by Ford. Other then that I think “not sure” that no other auto companies make their own glass parts. Does a company like PPG for example who makes some of the OE or OEM glass parts for Honda produce aftermarket parts for the same vehicles? are they restricted to not follow the OEM specifications for their aftermarket parts?

    • Glasseye said on 13-06-2012

      I stand to be corrected on this, but the way to identify an OEM glass is the Company logo/symbol ( e.g. Ford, Mercedes, Audi) will be stamped on the glass alongside the rest of the information you find on a glass. The same OEM manufacturer that supplies the glass to the carmaker can supply the ARG market, but it won’t have the carmakers logo on the glass. These ARG glasses may have some slight imperfections.

    • Bob Beranek said on 21-06-2012

      Quinn – I hope that I understand your question correctly.

      Question 1 – Some glass manufactures supply both OE parts and ARG parts. They would be categorized as OE manufactures for those vehicles they supply parts for and OEM manufacturers for those parts they supply to the ARG market. This is because they work off the same quality control requirements that are put upon the OE suppliers by the vehicle manufactures (VM). It wouldn’t make sense to scale back quality if they already have it in place for the OE.

      Question 2 – Carlite used to be wholly owned by Ford Motor Company but they were separated a few years back into its own company. In the past, some domestic VM also owned or had interest in glass companies. Today, most glass companies are independent companies and separate from the VMs.

      Question 3 – PPG Auto Glass is now PGW (Pittsburgh Glass Works). PGW does make some OE parts for VM and also make parts for sale in the aftermarket. Yes, they do make the ARG parts with the same specifications as the OE but they are not required to do so. For example. If one of the requirements is to have a specific logo emblazoned on the part for OE, it doesn’t mean that the ARG part has to have that logo also. As a matter of fact, it may be a contractual condition NOT to have the logo on the ARG part. However, it would be to the best interest of the glass company to replicate the OE part as close as possible to the ARG part because it would assure a quality product and appeal to the end user.

  7. Jeff said on 13-06-2012

    I agree as a shop owner that I would be interested in knowing what companies are considered ARG vs those considered OEM. That I can tell they all claim to be OEM. I might just be misunderstanding their marketing though…

    • Bob Beranek said on 21-06-2012

      ARG companies can say that they meet the OEM specifications which could LABEL them as an OEM but in reality they are not. OEM means ORIGINAL EQUIPMENT MANUFACTURER not an OEM specification follower.

  8. Daniel said on 14-06-2012

    For who might be concerned:

    In Europe, Pilkington provides original lites, especially windshields for GM (say Opel/Vauxhall, some Chevrolets [Spark, Aveo, Cruse, a.s.o.]) and they just laser erase the original brand signs replacing them with large Pilkington symbols. Same story about some Audi/VW windshiels, but in seldom cases.
    On the other hand, in Germany, I have dealed with Honda brand new vehicles glazed with XY Chinese original lites. Marked with “Honda” sign, no doubt.
    Market is diversifying, so all the aftermarket players must do.

  9. Daniel said on 14-06-2012

    ADVICE: try to identify the manufacturer by using the DOT reference number. Decision is to be adjusted upon your own trust, interest and expertise.

  10. Daniel said on 14-06-2012

    Yesterday, I have replaced an 2006 Audi A4 windshield, stamped with the “four circles”, but clearly signed with the Xin Yi Glass sign under, together with the explicit DOT number.
    The vehicle was legally imported from Germany.

  11. Gene Lopez said on 09-12-2016

    Effective January 1, 2017. The California Bureau of Automotive Repair has adopted “WINDSHIELD REPLACEMENT STANDARDS” under subsection 3365.1, Article 8, Chapter 1, Division 33, Title 16 CCR. In essence it says the automotive repair dealer must identify the cure time and not render the vehicle until the cure time has been met. Further more, the repairer must identify the windshield as either original equipment manufacturer part or a non-original equipment manufacturer part. Since you have described three, OE, OEM and ARG (aftermarket AM) I believe we should correct the BAR’s adoption.

  12. JJ Miller said on 11-10-2017

    Would love to see a decent article on the STRENGTH and performance of today’s auto glass verses 10 or more years ago. There is no doubt in my mind that the strength of glass is lessened. I used to walk on windshields in my garage to get to the rafters above… never an issue. Last week, I merely leaned on my Mom’s Prius Windshield (2009) to replace a wiper blade, it cracked from side to side and formed spiderweb design across the whole thing. Couldn’t have been more than 10 or 20 pounds of pressure. I was shocked. This week, her new windshield already has a rock chip crack. My 2001 Audi TT convertible got some pretty tough off-road use, never a chip. My 2017 Audi has been babied and has two small chips in the windshield already.
    Friends are saying the same thing.
    At one autoglass place, the kind secretary admitted, “We get lots more calls for replacement glass than we did in the past.” And, she talked about a man who was livid, saying “this is the third auto glass replacement in the last 6 months, and never had to replace or repair a windshield in last 40 years!” They have a brand new building on a major highway in our city (family business used to be off a side street) 2 years old.
    YES, i know that is all anecdotal. And that is why I would like to see an article.

    I am sure that the window glass is meeting safety requirements… but just because it is coated and will not shatter with sharp shards of glass, doesn’t mean it isn’t softer and much more likely to be damaged. I am sure my new audi and my brother’s new Toyota have OEM glass, that glass is easily damaged, much more so that 10 to 15 years ago.

  13. Michael said on 29-03-2019

    I’m trying to find out if ARG glass has a tendency to pit more than OEM or OE glass.
    Do you have any information on this?
    Currently my mom has some ARG glass in her Ford escape and it is horribly pitted but her paint is not pitted. ARG glass from a manufacturer called ACOUSTECH that seems to have another name below that one that says: CRINAMEX. I suspect this glass is made in Mexico – and that’s fine unless it’s inferior glass and susceptible to pitting.

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