I'm thinking about making a set of custom wheel spacers for my W123. I will locate them diametrically and bolt them to the existing hubs and I will tap them or put studs in the spacers for any bolt pattern I need. Material will be 7075 aluminum. The only limiting factor I see is that they will have to be .750" or so minimum thickness to have enough strength and thread depth for the different bolt pattern.

Advantages:

-use of wheels with different offsets

-use of wheels with different bolt pattern

-use of wheels with different locater diameter


I'm pretty much set on a 16" diameter wheel but that's about it.

Can anyone tell me why this wont work? I'm a CAD/CAM/CNC guy by trade so making them is the easy part. I just don't care for the selection of Mercedes wheels that will fit a W123.

Blackstack, I would strongly urge you not to use wheels spacers of any kind on your W123, and to only use genuine MB wheels with the proper offset. It's not worth the risk of injuring yourself or someone else using homemade wheel spacers. If you were to cause an accident as result of using said wheel spacers and your insurance company discovers that fact it could void your coverage.

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Fred Hoelzle

Yabbut you (or the insurance company) could use that argument for any alteration you make to the car that isn't stock. Can anyone tell me the safety issue? A thick enough piece of billet 7075 would be stronger than the axle flange itself and many times stronger than an aluminum wheel.

you can purchase spacers of varying thicknesses from online sources as well as proper lug bolts as well.

as long as it is hub centric you will be ok.

Blackstack, the fact that you are capable of making a "custom spacer" doesn't necessarily mean that you have the design engineering capability to ensure that the spacer provides the required automotive safety factor. Your proposed spacer design places at least twice the load on the spacer because it would undergo forces from the hub bolt and the wheel bolt in opposite directions. Whereas a typical spacer is sandwiched between the hub and the wheel using a longer lug bolt.

As you can tell I don't endorse spacers of any sort, let alone homemade types. If they were an acceptable alternative to proper size wheels MBUSA would use a few wheel styles on all their models with appropriate size spacers and lug bolts to match. I think you can realize that combination of different spacers and lug bolts would become a nightmare very quickly.

You're right about insurance companies denying coverage for non-stock safety related items that an owner installs for whatever reason. It's one thing installing an upgraded radio, but modifications to the suspension, braking, steering systems leave them an out.

Also, if your state mandates routine automobile safety inspections it's likely that your custom spacer won't pass. A knowledgeable, qualified tech would reject it.

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Fred Hoelzle

Huh? How do you figure? If you take a chain and pull 1,000 lbs. on each end the total force on the chain is still 1,000 lbs. It doesn't double like you're claiming. I didn't mention "homemade" anywhere in my post. Where do you see that? If I'm capable of designing and building $250,000 plastic injection molds I think making a set of wheel spacers off the clock at work wouldn't be too much of a problem.


No they wouldn't.

I've seen it said on these forums hundreds of times not to use wheel spacers but I've never seen a reason why nor have I ever seen someone post about a wheel spacer induced failure either. It all seems to me to be a bit of an urban legend of sorts.

Blackstack, in your original post you said "Can anyone tell me why this won't work?" Now, you refuse to accept the reason.

If you were so sure about your concept of a custom spacer why did you ask for feedback in the first place? I suggest you discuss your concept with an automotive engineer before proceeding any further. Better safe than sorry.

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Fred Hoelzle

Blackstack, let me reword Post #5.

A typical wheel spacer sees compressive forces from the lug bolts squeezing it between the hub and the wheel. So it acts like a shim with little chance of failure.

Your custom spacer will see tension forces in 2 opposite directions: the bolts securing the spacer to the hub pull in one direction, while the bolts securing the wheel to the spacer pull in the opposite direction. The resultant forces tend to pull the spacer apart, unlike the compressive forces on the typical spacer.

If you have difficulty understanding this explanation let me know and I'll try again.

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Fred Hoelzle

You told me why it wouldn't work. The only problem is that you were off in your calculations by two-fold.

Yea, I think you're going to have to explain it again for me. What you can't seem to wrap your mind around is the fact that there is no such thing as "tension forces in 2 opposite directions". Something is either under tension or it's not. 7075 Aluminum has a tensile strength of 73,000 psi. A piece .750" or so think would be probably 2-3 times as strong as the .250-.350 thick steel axle flange is. And the axle flange sees push/pull forces from top to bottom as it's rotating when cornering too so a .750" thick piece of 7075 aluminum bolted to it would actually reinforce the flange.

I think you are the one that would be served well by visiting with an automotive engineer. I'd even recommend a high school physics class as a primer first.

Blackstack, it seems that you're the expert. Go ahead and make your custom wheel spacer. Report back on how well it works.

Consider a patent application so you can profit from your invention.

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Fred Hoelzle

I run a 25mm spacer on the rear of my wagon and a 10mm spacers on the front of my wagon.


I have hit potholes, caught air, tracked it, done high speed runs, and drifted it. No problems to report.


What kind of spacer are you looking to run? One where the bolts pass through, or one where the spacer bolts to the hub, then the wheel bolts to it? I have the former on the front, and the latter on the rear. Both H/R hubcentric spacers.


O_o


I think alot of the people on here are completely against OEM stuff. Kinda sad! Carlsson and Brabus have certain wheels where "one size fits all" where its the same wheel for all cars, but include a spacer(s) to make them work on various cars.



Blackstack, are you looking to make wheels or just spacers to make wheels fit?

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-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

Blackstack, Just go make the spacers. I have this crappy 10mm on the front. I am in need of well made good ones.

If you make 10mm hub centric, bolt thru spacers, I'll buy them from you. I just have this OEM perfect wheel set that won't fit on my car because of the stupid limits of 'offset'

Let me know when you have them and the price...

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1987 300SDL 314K mi, counting; #22 Head
1999 E300Turbo 405K original miles
1997 E320 180K mi (Son's)
2002 ML320 (Son's)
1998 S320 140K mi (Son's) sold
1985 300SD 311K mi
1984 300D 324K mi (killed by a hit-n-run turd)
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Titanium?.... I made some, "adaptors", like Blackstack wants to, out of some Titanium left over from a job. I like the corrosion resistance of Titanium better too, but, they would be pricey.

Edited:
Just posted and realized that, "they would be pricey" sounded like I was trying to sell parts. Not the case, just meant to say that the spacers would be expensive because of the material costs and tooling.