Many people find themselves confused by this “Hollander number” that their shop talks about. The number is not located anywhere on the part… so where did the number come from? It came from the Hollander Interchange Manual, a book containing a wealth of information on everything from classic used parts to wheels and hubcaps, it’s basically the used parts bible. You always have to make sure you say what type of part you’re looking for when you give someone a Hollander number because the number could refer to multiple types of parts from different books.
Why is the Hollander number even used?
Oftentimes people are confused as to why people even use a Hollander number rather than just factory part numbers. That is a VERY good question, but there is also a REALLY good reason why. For a start, factory part numbers can be long and difficult to memorize. Hollander numbers are only 4 to 5 numbers long making them much easier to memorize and less likely to be confused when communicating them between people. The other major reason that people use the Hollander catalogue is that OEM parts (especially OEM wheels) tend to have multiple part numbers describing the exact same item.
Why would OEM parts have multiple part numbers?
Often when parts are manufactured in multiple locations, through multiple years or batches they have unique part numbers. This could be especially confusing for a part that is used for a long period of time because there could be four to five OE part numbers that all describe the same thing. Trying to find a replacement part would be extremely confusing if you had to know all of the different part numbers that can be used for the one part. Hollander has simplified this. They assign one number to describe all of those OEM numbers that could be used to replace the part. Here’s an example:
Hollander Part# 5044 (Describes an older GMC wheel)
GM# 12356740 ’95-02
GM# 12361578 ’96-97
GM# 12366741 ’96-97
Regardless of which part number is on the back of the wheel all three wheels look exactly the same, fit exactly the same, are made of the same materials and are all even manufactured by GM. Imagine if you needed this wheel and you had to call around to shops looking for that wheel with any of those different possible oem part numbers.
With the hollander number they are able to cross reference the single part number with anything else that would interchange for that same exact part. This simplifies everyone’s job!
Does everyone use Hollander numbers?
Most used parts retailers use Hollander numbers to identify their parts but dealerships have their own set of numbers they reference. Some companies use variations of Hollander numbers to help describe the part a little bit more. Often times while shopping for wheels you may see a part like ALY5309U85. This is still using a Hollander number. The “5309” is the part number the “ALY” is describing the material, for this is an aluminum alloy wheel, and the “u85″ is referring to the finish, this one being a chrome finish. If you were to find wheel part: #5309 on OriginalWheels.com it would show that it’s a 22″ Chrome Cadillac Escalade wheel with a picture beside the description. The great thing about that Hollander number 5309 is that if you found a 5309 on another site selling wheels it would be a wheel that has the exact same description (but possibly not the same quality!).
On the OriginalWheels.com site, you may have noticed that we will normally just give the “Wheel Part Number” which will match up to the Hollander Number, and then we describe the finish in words so people don’t have to know the “U code” to know what they’re ordering.
Anyone can own a Hollander Book. They can be purchased directly from the company at https://hollanderinterchange.net/ and cost $24.95+ depending on which manual you need.