10mm rear spacers - Educate me!

[SteveYem]

I was gearing up to buy 10mm hubcentric spacers to use with the 666m wheels on my 2018 ZCP M3 when I read that the typical hubcentric style 10mm spacer, e.g. the ones offered by CTS Turbo, will not work because the stock hub protrudes too far into the spacer bore and prevents the spacer from sitting flat against the brake rotor hat. OK, I understand that. Then I considered getting flat 10mm spacers for the rear but read that results in only 2mm of hub protruding past the spacer which is arguably not sufficient engagement length into the wheel bore to offer adequate support.

So, for everyone running 10mm spacers in the rear on an F80/F82, which spacers are you using? Is the only 'right' solution the ones offered by Turner with the 'hub extender' feature?

[M3SQRD]

Originally Posted by SteveYem

I was gearing up to buy 10mm hubcentric spacers to use with the 666m wheels on my 2018 ZCP M3 when I read that the typical hubcentric style 10mm spacer, e.g. the ones offered by CTS Turbo, will not work because the stock hub protrudes too far into the spacer bore and prevents the spacer from sitting flat against the brake rotor hat. OK, I understand that. Then I considered getting flat 10mm spacers for the rear but read that results in only 2mm of hub protruding past the spacer which is arguably not sufficient engagement length into the wheel bore to offer adequate support.

So, for everyone running 10mm spacers in the rear on an F80/F82, which spacers are you using? Is the only 'right' solution the ones offered by Turner with the 'hub extender' feature?

Order the Turner 10 mm spacer with hub extender and it will work on the stock hub. Other option is to grind down your hubs by 1 mm and it should work with all 10 mm spacers. The problem is the nominal hub length is 10 mm but a lot are < 10 mm too. For a 10 mm spacer, a 10 mm hub will bottom out on the spacer so the spacer isn’t sitting flush on the mounting brake rotor hat.

[SteveYem]

Originally Posted by M3SQRD

Order the Turner 10 mm spacer with hub extender and it will work on the stock hub. Other option is to grind down your hubs by 1 mm and it should work with all 10 mm spacers. The problem is the nominal hub length is 10 mm but a lot are < 10 mm too. For a 10 mm spacer, a 10 mm hub will bottom out on the spacer so the spacer isn’t sitting flush on the mounting brake rotor hat.

Thank you (as always!) for the clear and thorough feedback. I had a feeling I was going to have to spend the big bucks on the Turner offering, but wanted a sanity check before pulling the trigger.

Of course, I'll get them and then decide I really wanted 12mm after all....

[M3SQRD]

Originally Posted by SteveYem

Thank you (as always!) for the clear and thorough feedback. I had a feeling I was going to have to spend the big bucks on the Turner offering, but wanted a sanity check before pulling the trigger.

Of course, I'll get them and then decide I really wanted 12mm after all....

I’ve never had an issue with Turner extended hub and standard hub. You could measure the length of the hub centering ring before buying. I’ve been able to use standard 10 mm spacers on my e92 M3s without issue.

[heymarkv]

Any 10mm hubcentric spacer should work just fine. Anything less than 10mm wouldn’t have a hubcentric lip built in as they’re too thin / small.

I have 10mm, 12mm, and 15mm Burger Motorsports wheel spacers, never had any issues.

[M3SQRD]

Originally Posted by heymarkv

Any 10mm hubcentric spacer should work just fine. Anything less than 10mm wouldn’t have a hubcentric lip built in as they’re too thin / small.

I have 10mm, 12mm, and 15mm Burger Motorsports wheel spacers, never had any issues.

A 10 mm spacer works 75-80% of the time but the remaining 20-25% have hubs with 10-11 mm long centering rings. You can easily slide pieces of paper in between the wheel mounting face and the brake rotor mounting hat. It’s a known issue going back generations. Yes, anything <= 10 mm thick requires hub extenders like the Turner 5, 8 and 10 mm thick spacers with integrally machined hub extenders.

[heymarkv]

Originally Posted by M3SQRD

A 10 mm spacer works 75-80% of the time but the remaining 20-25% have hubs with 10-11 mm long centering rings. You can easily slide pieces of paper in between the wheel mounting face and the brake rotor mounting hat. It’s a known issue going back generations. Yes, anything <= 10 mm thick requires hub extenders like the Turner 5, 8 and 10 mm thick spacers with integrally machined hub extenders.

It’s wheel spacers, he’ll be fine running any brand hubcentric 10mm+ spacer.

Macht Schnell is another brand wheel spacers that the majority of BMW owners run.

Also less than 10mm its recommended to run a stud kit.

[M3SQRD]

Originally Posted by heymarkv

It’s wheel spacers, he’ll be fine running any brand hubcentric 10mm+ spacer.

Macht Schnell is another brand wheel spacers that the majority of BMW owners run.

Also less than 10mm its recommended to run a stud kit.

It’s not. It’s been a known issue and I had it with Macht Schnell 10 mm spacers on one of my e92 M3s - fit properly on one, didn’t fit the other. Both hubs were rust free and both have PFC aluminum machined mounting hats. Measured length of one was 10.2 mm and 9.4mm on the other. Why does Turner make a 10 mm spacer with a hub extender? It allows them to design a spacer with an internal depth of 9.0 mm so it fits all BMWs and has an extended hub to give you > 10 mm of hub engagement.

EDIT: See note three on BW 5, 12, 15, 18, and 20 mm thick spacers. Notice no 10 mm spacer? There is also a video on the paper test to verify your spacers are sitting properly on the hub. Furthermore, spacers have a manufacturing tolerance so no two spacers are identical (off by a few mils on different features.

https://www.bimmerworld.com/BimmerWo...pacer-Set.html

[heymarkv]

Originally Posted by M3SQRD

It’s not. It’s been a known issue and I had it with Macht Schnell 10 mm spacers on one of my e92 M3s - fit properly on one, didn’t fit the other. Both hubs were rust free and both have PFC aluminum machined mounting hats. Measured length of one was 10.2 mm and 9.4mm on the other. Why does Turner make a 10 mm spacer with a hub extender? It allows them to design a spacer with an internal depth of 9.0 mm so it fits all BMWs and has an extended hub to give you > 10 mm of hub engagement.

EDIT: See note three on BW 5, 12, 15, 18, and 20 mm thick spacers. Notice no 10 mm spacer?

https://www.bimmerworld.com/BimmerWo...pacer-Set.html

Turner’s just has a hub cap integrated that’s the only difference. It’s spacers the world’s simplest mod lol

[M3SQRD]

Originally Posted by heymarkv

Turner’s just has a hub cap integrated that’s the only difference. It’s spacers the world’s simplest mod lol

Sure but that doesn’t change the fact that the issue with 10 mm spacers has been known for 16-17 years. Why would Turner complicate “the world’s simplest mod” wheel spacer design if a 10 mm spacer without an extender is a universal fit without it? Do you not believe BW? Do you not believe me? I had to grind down the longer hub by 0.8 mm to get the MS 10 mm spacer to fit. The difference in thickness of the PFC mounting hats was 0.0005 mil (0.0127 mm). The problem was the hub length.

[heymarkv]

Originally Posted by M3SQRD

Sure but that doesn’t change the fact that the issue with 10 mm spacers has been known for 16-17 years. Why would Turner complicate “the world’s simplest mod” wheel spacer design if a 10 mm spacer without an extender is a universal fit without it? Do you not believe BW? Do you not believe me? I had to grind down the longer hub by 0.8 mm to get the MS 10 mm spacer to fit. The difference in thickness of the PFC mounting hats was 0.0005 mil (0.0127 mm). The problem was the hub length.

From all the threads, shop posts etc that just “put spacers on wheels / OEM wheels” and never have issues exponentially outweighs this 1 odd experience. 🤷🏻&zwj;♂️

[M3SQRD]

Originally Posted by heymarkv

From all the threads, shop posts etc that just “put spacers on wheels / OEM wheels” and never have issues exponentially outweighs this 1 odd experience. 🤷🏻&zwj;♂️

Clearly BW’s experience is based on more than one experience and this known issue goes back to ~2006-2008. My “odd experience” is a real world example and it’s not limited to one. 10 mm spacers don’t fit on my wife’s ‘18 f22 m240ix - just another fluke? What’s the probability, if it’s limited to only one “odd experience” case, that the same person would have two cases of 10 mm spacers not fitting properly on two different BMW models/generations of cars? I doubt the curve is exponentially growing because that would mean only a finite number of cars can use spacers as the curve hits its asymptote. Blindly putting on a 10 mm spacer may result in major issues. Did you watch the BW video? I doubt it because you’re an expert in the world’s simplest mod. I guess those issues (you’d know if you watched the video) also don’t happen on 10, 12, 15, 18 and 20 mm spacers. Again, blindly saying all spacers fit properly is a dangerous uniformed statement. It’s fine if you want to ignore this risk but don’t blindly tell other people it’s not a real issue. I guess you’re similar to the Orange Jesus in that if you say something that is factually wrong, it makes it come true.

[Colinv6]

No issues at all with my Bimecc 10mm all round, Infact I thought this was purely an e92 issue. Seems not but there’s a ton of people running 10mm with zero issues.

[M3SQRD]

Originally Posted by Colinv6

No issues at all with my Bimecc 10mm all round, Infact I thought this was purely an e92 issue. Seems not but there’s a ton of people running 10mm with zero issues.

It’s not limited to the e9x. BMW isn’t going to change their design so a 10 mm spacer can be used. Think about it if you have a hub with nominally a 9.5-10.4 mm length it’s hard to design a 10 mm spacer which has its hub starting at 10mm. The counterbore depth is similar to the height of the stock hub so they bottom out. Have you tried putting a piece of paper between your hub and spacer? Even a fraction of a mm, the spacer is not sitting flush with the mounting hat. I wouldn’t be surprised if 30% of the people running 10 mm spacer doesn’t know their spacer isn’t seating properly. I had to grind down my wife’s f22 (F series) hub to use a 10mm spacer. Its looks seated but I could slide paper in between the hub and spacer. G series also have 10 mm spacer issue.

[Colinv6]

Originally Posted by M3SQRD

It’s not limited to the e9x. BMW isn’t going to change their design so a 10 mm spacer can be used. Think about it if you have a hub with nominally a 9.5-10.4 mm length it’s hard to design a 10 mm spacer which has its hub starting at 10mm. The counterbore depth is similar to the height of the stock hub so they bottom out. Have you tried putting a piece of paper between your hub and spacer? Even a fraction of a mm, the spacer is not sitting flush with the mounting hat. I wouldn’t be surprised if 30% of the people running 10 mm spacer doesn’t know their spacer isn’t seating properly. I had to grind down my wife’s f22 (F series) hub to use a 10mm spacer. Its looks seated but I could slide paper in between the hub and spacer. G series also have 10 mm spacer issue.

BMW fitted mine when they did the MPHAS kit, so it could all be aligned and stuff with spacers on. Surely if it’s not seated 100% there would be a shimmy or vibration, mine has none, zero.

[M3SQRD]

Originally Posted by Colinv6

BMW fitted mine when they did the MPHAS kit, so it could all be aligned and stuff with spacers on. Surely if it’s not seated 100% there would be a shimmy or vibration, mine has none, zero.

That doesn’t mean it’s been fitted properly. You’re putting loads into the five wheel bolts/studs and the spacer bends (hub could also be bent outward) when the as the five lug holes/studs-nuts when you apply 105 lbf-ft torque. This is what results in the spacer being bend downward relative to the hub. Additionally, after all bolts/studs are torqued, the spacer central hub will sit higher relative to the bent spacer. The Hub gap increases as you move outward from the ID to the OD. The gaps are on the order of 1-5 stacked sheets (paper has a thickness of 3 mil so the stacked sheet gap is 3-15 mil).

You may have a f82 with 9.5 mm hubs but I’d definitely still check the full circumference with the paper test. Even thicker spacers have this problem due to non-colanar machining issues between its top and bottom mounting surfaces. I’d guess this issue plaques 25-30% of f8x, f2x, f3x, g8x, e92 M, etc…as well as most M and non-M series from ~2008 to present.

[Weißbier]

I wanted to bring some visual context to this thread. I fitted one of my BMS 10mm spacers in the rear (1st pic), and it seems to fit fairly flush against the brake hat without play. Second photo is the Turner 10mm where you can see how the "teeth" of the hub fit into the slots on the backside of the spacer. Last pic is the Turner spacer fitted to the hub.

[SteveYem]

Originally Posted by Weißbier

I wanted to bring some visual context to this thread. I fitted one of my BMS 10mm spacers in the rear (1st pic), and it seems to fit fairly flush against the brake hat without play. Second photo is the Turner 10mm where you can see how the "teeth" of the hub fit into the slots on the backside of the spacer. Last pic is the Turner spacer fitted to the hub.

Thank you for that!! I ended up shelling out the big bucks on the Turner 10mm spacers with integrated hub extenders for the rear, and will go with BMS 10mm spacers for the front. I am waiting for both to arrive. Since there seems to be some variability in the height of the rear hub 'jaws' from one F8x to the next, I am planning to test fit the BMS 10mm spacers on the rear hubs to see if they'll work on my specific car. If so, I'll return the Turner spacers and buy another set of the BMS.

[theweebabySeamus]

BW and Turner both have a great amount of practical experience. If they say a hub extender is needed, thats enough for me.