Hi, Folks.
A few issues seem to come up again and again regarding wheels and I thought it might be useful to put together some information in a single thread; I included the word
breathing in the thread title since it should have a life of it’s own and grow accordingly over time.
But first, a caveat: some of the information below has been gathered from other sources and some is the result of my direct knowledge and experience; I accept no responsibility for either.
That said, my goal here is to provide information that is as accurate and complete as we can make it -- over time. So if you see something that’s factually incorrect, feel free to add to the thread (or PM me or another W210 mod) and that way the initial information can be edited, thus saving people from reading through the entire thread in the future to correct a typo, etc. (However, if it’s something with which you simply disagree, please be helpful and post in this thread along with a notation that it is just your opinion.)
Let’s start with some basics. All W210 models use the “standard” MB lug pattern: 5x112 (5 lug bolts evenly spaced 112mm apart). The lug bolt used by all US W210 models has a ball seat mounting that is R12 and has a 12mm shaft with a 1.5 thread pitch that is 61mm in overall length (commonly referred to as a “R12-12Mx1.5x61mm” or similar nomenclature). That said, I have heard stories from folks - who swear their cars are stock - to the effect that their bolts are different, so take that with a grain of salt. Also, the older W210s had lug bolts that were much longer (85mm?) as they had a shaft that extended
above the ball seat to put the head of the bolt out nearly flush with the wheel surface; however, this did not change the functional length of the bolt and the newer style can replace the older.
Contrast this with aftermarket wheels; many manufacturers opt for a conical (or cone) seat, so if you’re buying aftermarket wheels, be sure to source with them (preferably from your seller!) the proper lug bolts.
I can’t stress this fact strongly enough: Do not assume that lug bolts are interchangeable; the use of lug bolts that do not properly match the chassis as well as the chosen wheel may (and likely will) result in damage to the wheels, the hub, the brakes - and quite possibly you and others.
There are many potential issues with respect to wheels and, particularly, wheel interchangeability from other MB models. However, two predominate: lug bolts and "offset".
Lug Bolts
As noted, the W210 uses a 12M bolt with the 12R ball seat. However, newer Benz models (including the 211, a popular rim choice for W210 owners) use a 14M lug bolt with an R14 ball seat. Obviously, you cannot thread a 14M bolt into a 12M hole; however, you cannot properly use the 12M, 12R bolts in a wheel designed for R14 bolts. Raymond provided a picture that approximates what happens when a R12 ball seat is mated to an R14 wheel:
This unsafe issue can be resolved by sourcing custom lug bolts that have an R14 ball seat and a 12M bolt. In my experience a non-AMG W211 wheel will fit on a W210 chassis with a bolt that is R14x12Mx1.5x26mm. These can be obtained from a few sources; one is
RadUSA Direct's Home Page.
Offset
As noted, the other significant issue is offset. Offset is a variable that refers to the difference between the true centerline of the wheel and the mounting surface on the hub. Referring to the diagram below, the chart on the left shows stock wheel sizes and offsets for the W210 chassis in US-spec. On the right is a diagram depicting offset measurement.
Zero or “no” offset means that the mounting surface is even with the centerline of the wheel.
Positive offset occurs when the mounting surface is closer to the front side (the outside) of the wheel. Conversely,
negative offset results when the mounting surface is closer to the back side (the inside) of the wheel. If you think of a deeply-dished wheel, this would have a significant amount of negative offset.
A couple of general points may be made. First,
given the same wheel width, as you increase positive offset (or decrease negative offset) you effectively move more of the tire and wheel inside towards the suspension components. Second, while small changes in offset are acceptable, using an offset that varies significantly from the manufacturer’s specifications can result in unintended effects on handling as well as improper bearing loads.
Assuming you want to replace your stock wheels (or at least those currently on your car) with different ones, it’s important to determine the effect of the change in offset. As an example, my W211 wheels (17x7-1/2J ET 38) with their stock 245/45-17 tires rubbed in the front at ¾ lock and beyond. With a different offset, say ET34, they would not have rubbed. However, replacing those tires with 235/45-17 was the right answer anyway as that is the correct size for the W210 chassis as it maintains the proper OD for the tire.
Accordingly, as you begin your quest for replacement wheels, start with your current wheel size (diameter, width and offset) and your proposed wheel size (same dimensions from the new wheel) and plug those numbers into an offset calculator.
Caveat: Don’t simply rely on a chart or graph of wheel dimensions. The best suggestion here is to dismount one each of your front and rear wheels and read the dimensions off of the wheel: they should be stamped or cast right on the inside of them. This does a few things (beyond assuring that you have the correct dimensions). If you have a staggered wheel setup, you won’t accidentally source the wrong wheels. Also, while you’re in there it permits you to inspect the brakes (how many pins do I have on the rear brakes?) and suspension (spring perches, leaky shocks, worn sway bar links, etc.).
So once you have the dimensions for your current wheels and the ones you are considering, plug them into an offset calculator. There are several on the web, one good one is Mark Sink’s at:
Wheel Offset Calculator.
I hope that helps.
As always, take care and enjoy the ride!
Greg
looking silly
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