3mm spacer purchase advice needed
 

After reading many threads, it seems that 3mm spacers can be simply slipped on without the need to use extended studs. The OEM lug nuts can be installed normally and everything will be fine. Is this correct?


It seems that the hub extends 10mm to accept the wheel. After 3mm is taken by the spacer, only 7mm is left. Then how 'thick' is the wheel where it is mounted to the hub? Just curious.


There are two choices on Amazon. First a cheaper one, $7.5 for a pair


https://www.amazon.com/UberTechnic-5...dp/B01NBG02ZB/


next one is $17 for 2.


https://www.amazon.com/StanceMagic-H...dp/B01M623A6I/


I am confused why the 2nd is more expensive (and maybe better)?


Thanks for any advice!

Yes you can have a 3mm spacer for stock. The only thing you need them for is a 17x9 +45 wheel to clear a factory strut in front. I have those exact cheaper ones on mine. No Issues. The others are hub-centric, which you don't really need for a slip-on spacer.

if you want high quality spacers and maintain the full 10mm of hub to wheel

http://www.motorsport-tech.com/4DCGI...s_err_ymm.html

Be aware the minimum thickness necessary to machine a lip for being hub centric is 6mm.


For 3mm you don't need the spacers to be hubcentric because the hubface extends past the spacer itself. These are ONLY really useful on stock suspension to get a 17x9 +45 offset wheel flush (+42 is correct flush offset) as mentioned earlier in the thread. There is basically no other reason to ever use a 3mm spacer on this platform.


If you're planning to lower the car or otherwise change the suspension geometry, you should do the appropriate calculations to find the spacers you need and then yes, order from Motorsport Tech, top notch quality and worth every penny. I trust my life to their products on the race track. I would not trust my life to whatever is cheapest on Amazon.

They are very useful for fitting wheels over big brakes

This usually requires a 10mm spacer in most applications. Obviously spacers are available in many sizes for just such a reason, but for common wheel offsets including stock wheels, a 10mm spacer is usually most helpful. Of course once you change suspension geometry from stock it becomes a much wider variety...

I guess I still do not get the meaning of hub centric for a spacer. For a wheel, hub centric, to me, means the opening of the center hole has the same diameter as the diameter of the hub. Or very slightly larger.



So for a spacer, as long as its center opening is the same, it should be hub centric. For the 2 Amazon ones, in fact the center openings for both are beveled. So I think as long as the smaller end has the same diameter, it is hub centric. In fact, both spacers have 'hub centric' in their titles. So what I don't understand are the following 2 remarks.


1. "maintain the full 10mm of hub to wheel"


How can I put a spacer and maintain full 10mm hub to wheel? The spacer will have to take away 3mm.



2. The minimum thickness necessary to machine a lip for being hub centric is 6mm.
What do you mean exactly in this sentence? Does it mean since I still have 7mm hub extended out of the spacer, adding a 3mm spacer is still hub centric. but adding a 5mm won't be since only 5mm is left?



It is also interesting that the guy in the following video says that we can use up to 5mm slip-on spacers with stock wheel studs.


https://www.ft86speedfactory.com/fac...l#.XYUCm2Z7lzk

No. I have tried several sets of wheels that only need a 3mm or even 2mm spacer to fit. See the PP brakes thread for a lot more.

What I said comes from my discussions with Motorsport Tech (I own many spacers from them in various sizes). It's about the machining process, has nothing to do with how much hub face will be exposed in a given size spacer.


Hubcentric means that the spacer is sized such that it's center bore matches the hub, and it provides a bevel on which the wheel's center bore sits. Most aftermarket wheels have a larger center bore than the size of your hub so you use hubcentric sizing rings to bring it into line (for instance commonly 73.1mm or 65mm for center bore of aftermarket wheels, our cars have a hub diameter of 56.1mm).


You can run up to a 5mm spacer on stock studs, however I think that's kind of sketchy and most of the better quality 5mm kits include slightly extended studs (like H&R Trax+). 3mm though does not need extended studs at all, nor do they need to be hubcentric, because the lip of the hub face will extend past the spacer.

I'm interested in hearing about those people that have died from using "cheaper" spacers.

FWIW I have 3mm spacers in front, but not because of the PP calipers. I needed them due to my camber settings and tire sidewall since without them the tire was very slightly brushing past the strut perch.

Well I read more about hub centric. There's hub centric for the spacer and hub centric for the wheel.

Any spacer that has the same center bore as the hub will be hub centric because the hub helps to center the spacer. Any spacer that is less than 10mm thick would be hub centric for the wheel automatically, because the hub will stick out and center the wheel. The space doesn't have to do anything.

Of course, if the hub only sticks out 1mm, it might not be long enough to really help to center the wheel. So someone might say you need to have at least 6mm of hub exposed to really center the wheel. So if the exposed hub is initially 10mm, any spacer thicker than 4mm is ineffective as to center the wheel in practice.

So any spacer thicker than 4mm requires extended studs for lug nuts to properly seat, and requires the sapcer to have a lip to center the wheel to be hub centric for the wheel.

Of course when the spacer is thick enough, it is easier to use a bolt-on spacer rather than a set of really long lug studs.

An interesting observation is that using spacer, especially the silp-on type is a lot easier for German cars. They can simply use longer lug bolts and there's no need to mess with lug studs and hub assembly.

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I don't know of anyone who has died, but I have seen people who used cheap bolt-on spacers have the lugs on the bolt-on spacers shear during hard braking. I've also seen a car get black flagged in for wheel wobble and it turned out their slip on had cracked and disintegrated which luckily was caught before anything truly bad happened... they had slightly damaged wheels and needed new spacers, but otherwise no harm. Both could have been catastrophic under different circumstances.

Generally speaking, if I'm putting something on a car going on a race track, I'm using the highest quality parts available. Taking unnecessary risks is just dumb.

Spacers are perfectly safe if they're properly made and properly installed... but otherwise they can be problematic.

I am using ARP extended studs and H&R slip on spacers myself so should be safe but was just curious since people always say catastrophic things happen when going cheap on spacers.

For a slip on to crack and disintegrate seems odd. Almost like a washer being a problem between a bolt and nut, doesn't happen much. Maybe they didn't tighten everything down and it wobbled enough to actually damage the spacer. Then blame was put on the cheapest part? I am 99% sure the dealer did me that way. Soon after a dealer oil change and I had them rotate the tires, I began having a clicking noise happen when I turned the car only one way, I think left if I remember correctly. Turned out the lugs were just a little more than hand tightened on that one wheel. It only went on for a couple days and a few miles before I realized what it was.
Shearing all the bolts off seems like it would be over torquing it all down like what happened here: https://www.newcougar.org/forums/pro...-fell-off.html
Every horror story online is from over torquing or not enough like what happened to me. I'd be willing to bet both of your examples were the same. Not to say I would cheap out on spacer or bolts. They are after all holding on what one could argue is the most important part of the car.

After reading this: on bimmerforums.com, I wonder now if buying my ARP studs at on Ebay online store was safe. Looked into to it even further and found this: https://www.thecounterfeitreport.com...486/Bolts.html
I didn't get them for cheap and of course not used but that link says to only buy the studs from a authorized dealer which I would imagine is not an Ebay store. What I bought: https://www.ebay.com/itm/ARP-Wheel-S...72.m2749.l2649
I paid $130 at the time, not sure why they're $160 currently as every other place right now is still about the same $130. Seller has 99.99% positive feedback so everything he sells should be on the up and up I would hope.

I bet this guy in the video below is the owner of such fake ARP product: [ame]https://www.youtube.com/watch?v=dnwnb8myWKo[/ame]