MUST WATCH if you run WHEEL SPACERS - VERY important SAFETY tip!!!

A quick PSA for anyone that runs wheel spacers for the street or track - this quick test could save you from a LOT of problems in the future, money from repairs, and from possible disaster.

A proper hubcentric spacer slides over the hubcentric lip of the hub, which protrudes approximately 10mm. But the outside diameter of the hub the spacer is covering becomes the same outside diameter that the spacer must have to be hubcentric, so there must be a connector linking the spacer pad to the spacer’s hubcentric snout, which is in the form of a chambered feature. All wheels have a matching chamfer relief, but there is no standard dimension in wheel nor spacer brands for this dimension, and we see it even vary with production runs. And if you are using a spacer with a larger chamfer (typically used to give the spacer more strength) with a wheel that has a minimal chamfer relief, you are at risk of having a failure!

If using a large chamfer spacer with a small chamfer wheel, the wheel will rest against the spacer’s chamfer instead of the spacer pad itself causing the wheel to not be mounted flush. The wheel is never then seated flat on the wheel pad with the wheel studs or bolts providing only a clamping force. Instead, when hitting curbing for example, the hubcentric lip is not loaded as intended, and the load will instead transfer into fasteners, which may result in a premature stud failure. You can see if this spacer to wheel interference has occurred easily by looking for a witness mark along the spacer’s chamfer.

We strongly recommend testing all wheels and spacers you use with what we internally call "the paper test". Once the wheel and spacer are removed from the wheel, place a sheet of standard paper between the spacer face and back of the wheel mating surface and apply pressure. The paper should be captured by the wheel spacer and not able to be pulled out of place. If the spacer “rocks” on the chamfer in the hub then the paper will not be secured and the spacer and wheel have failed the paper test.

If the paper test fails, you should immediately discontinue use of that spacer/wheel combination, and evaluate potential fatigue on your wheel fasteners. When I have been at the track in the past with a small interference, I have used a barrel sander (or even a piece of sandpaper wrapped around a socket) to increase the chamfer relief on a wheel to fit properly - I wouldn't call this the correct solution, but it's gotten me out of a few jams. If you're not as pressed for an immediate solution, a different spacer is a good solution (10mm spacers have the most observed issues because of the more aggressive chamfer required due to the hub's 10mm lip extension - consider moving to a 12mm). If your spacer to wheel interference is excessive, you may have fatigued your wheel fasteners and accelerated replacement may be prudent.

Thank you for reading, and please do share with your track and race friends. The lack of standardized dimensions makes this an issue, but making the paper test a standard part of a fitment test for any new set of wheels or spacers (even if they are the same brand you already own), may save you some headache down the road.

#bimmerworld #safetyfirst #BMW

[FriendM]

Perfect timing. Need to use spacer for first time. Thanks for taking the time to make this video. This is gold. 👍

[bmwsm]

Absolute must check. People who complaint about wobble or vibration often have the wrong or cheap wheel spacers. I use BBS and H&R spacers on track only and I still check the wheel and spacers for crack or damage after EVERY track weekend. When you wash your wheel after a weekend events its not just to clean them but look for bend and cracks.

[sandweiler]

Very simply presented with logical explanation. I am about to put spacers on my Mazda Mx5 ND2 for daily driving (no tracking intended ever). But I will go for sure for top of the range spacers. Price is not an issue when your life depends on it.

[dj]

Great info! Pulling my wheels tomorrow to do this paper test. Thanks!

[bwedges]

I'm going to say something very stupid; if a racecar can use spacer without issues, im going to put it on my road car, as long as i can find high quality spacers and proper installations.
You can't stop me this time scotty!!!

[gmans]

Can only smash the Thumbs Up once. That much more attention to the details. I need to share this Immediately! My son and I are always VERY CAREFUL and VERY CAUTIOUS about the things that are between your butt and the road!

[pngts.g]

Very simple, yet, very informative!
Thanks for the video!

[salami]

great info! will use this to check new ones

[karlt]

EXCELLENT information in perfect demonstration

[baduncadonk]

Appreciate this video; learned useful stuff.

[stickiefinger]

Time to start manufacturing a tool for the general public to buy and take down the material on the wheel or the spacer. Maybe large counter bore or a conical sand paper attachment on a drill.

[j_d]

Great video now i feel better about putting spacers on my car.

[MurkSeason]

This is actually great info, thanks trying to put 2 inch spacers on my 06 ser

[MrRGBTV]

Who knew? Great info and demo, James. Thanks for that!

[harryberry]

Refreshing to see a video on hub and lug centric spacer and more importantly the chamfer on both wheels AND spacers, I've been aware of it for a very long time and it's so important, another thing that wasn't touched on here are hub rings which can add more problems to watch out for because those hub rings chamfers have to match or be deeper than the wheel spacer. To avoid that possible issue I look for wheels that fit my hub W/O hub rings in other words hub centric wheels. A long time ago I learned something that for younger folks might not even know and that little hub that protrudes out from your axle is meant to bear the weight of your car along with centering the wheel and in the beginning aftermarket wheels were made for specific cars to fit like a stock wheel, it was difficult to find aftermarket wheels early on but then aftermarket manufactures started making the hub bore larger on their wheels and those wheels had different hub rings for different cars and here we are today just about any wheel you desire might be able to fit...remember what I said about the axle hub bearing the weight of the vehicle than think about thermo plastic type hub rings see a potential problem there? If you track your car (or Race) better stick with hub centric wheels the trend of one large hub bore for all isn't as prevalent as it once was thank god.
Reminds me of "Jaws" you get in the cage, cage goes in water ...shark in water...farwell and adieu.

[off-roadingexplained]

Thanks!!! I will definitely do this test!

[gixxerhoff]

Great Video. Nothing worse then breaking a wheel stud

[PropDeskJunkie]

Wow…happy I found this. Learned something new today. Thanks Clay!

[bewithU]

Great info.
Apex wheel do not recommend 10mm spacers for the same reason. The part where the hub goes into the spacer may not fit flush, leaving a gap between the hub and spacer. So they recommend a minimum of 12mm. I just found this out since I broke a stud (probably from this and also did not swap out studs after certain period of time).
Now I understand there is also the fitment issue between the spacer and the wheel. I will check both side of the spacer fitment, hub-spacer-wheel.
I installed the Bimmerworld racestuds. A little more costly but shotpeened and each stud individually inspected.

[cyclistman]

Interesting and informative video, kudos. One would think that the manufacturers of wheel spacers and wheels would collectively come together and standardized such a critical detail for the safety and well being of their end users. 😳 I still think wheel spacers are a bad idea for street cars for other reasons besides the issue stated here.