F80/F82 suspension/brakes backwards compatibility catalogue thread

[Richbot]

We have our M4 brakes thread, and that's got me thinking what else does the F8x have that's trick

So, we know:

- F8x front uprights fit (very very slightly lighter than E9x according to realoem, but more importantly, available with camber built in, about $370 each)
- F8x brakes bolt on with some brackets, or with F8x uprights (located in this thread): https://www.m3post.com/forums/showthread.php?t=1375975
- F8x front and rear hubs can be retrofit to existing E9x uprights/spindles/axles https://futureclassic.us/collections...b-retrofit-kit
- One can even upgrade to F8x CCB's, if one is dumb enough: https://ind-distribution.com/product...9X-34112358378

What else? I saw a pic of the F8x front hub, which is very trick and motorcycle-like in comparison to our front hubs, and according to Realoem, is almost an entire pound lighter per side. The M4 brakes thread got me wondering if we could use these on our cars as a direct swap, because the E9x hub fits on the F8x front spindle/carrier/upright. The only difference, to me, appears to be the M4 part had a lot more machining after the parts were cast (expensive)

Photos courtesy of ECS Tuning

E9x part, OEM BMW is $327 right now


F8x part, OEM BMW is $300 right now This photo is 31202284235 (superseded by 31207857506 but no photos of the superseded part which looks identical on realoem):


You'd need to figure out which bolt works (F8x takes a shorter 45mm bolt, same pitch and size) and you'd need to use M14 studs up front, but some people are upgrading to those anyway. I can't recall how the wheel speed sensor is triggered up front, but that could be a problem too. I dunno where the hall effect is coming from up front, if it's the bearing itself it's looking for or the hub spinning or what

Anybody have any other hard data or speculation on retrofit possibilities?

[SYT_Shadow]

The F80 hub is a piece of engineering! It would be awesome to upgrade

[wyatth]

That hub looks trick, would be cool to confirm it fits (and if it added a little more offset). Is there any benefit to them other than looking nicer and saving a little weight? I could see going with them if you need to replace anyway, but if they aren't needed for a brake retrofit, is there anything other purpose?

Damn. F8x spindles, hubs, and brakes would be a nice OEM swap. Those spindles are too damn expensive - $670 for the pair on ECS now, $600 for hubs, 1220 for rotors ... $2500 and don't even have calipers, pads, or fluid. Dropping the hubs and finding a deal on lightly used calipers could make it palatable.

[Kisenwether]

I have the ecs tuning gold ceramic calipers kit for the front of my e92 and always wanted to finish the kit so I recently just finished making the brackets so I will have the full ceramic calipers on iron rotors. I enjoy having the OEM+ upgrade.

[SYT_Shadow]

I would just like to use that hub with oem e9x brakes. It's a really nice piece!

[Richbot]

It's neat right? Like those wave rotors on Audis, except for the hub. Nevermind M14 studs mean I have to change lugs and studs AGAIN, I still want them on my car just for the machined reliefs. Extra metal is for wimps

Somebody will have to check it out sometime.

I doubt there's any other upside than maybe looking a little neater when you have the car taken apart and half a pound per side of weight savings. It's not like people chew through front hubs on these cars on track now, they are pretty damn stout and if anything I'd think F80 might be a little lighter duty considering the F83 is ~200lb lighter than E93.

[Redd]

Yeah the E9x M3 hubs are solid as a tank. Would be a pity if the F8x pieces weren't at least as strong, even if they look better.

[Richbot]

The crankshaft hub is the only hub I've read about people needing to get fixed so far on the F8x

[slonik]

i like f8x rear subframe. it looks excellent.

anybody tried to install it?

i'm even have f82 in our workshop now, but have no free time, to dismount all this parts to check this.

[Richbot]

I can think of a dozen reasons why it'd be insane to bother trying, but I'd love to see somebody try

Retrofitting the F8x e-diff might almost be worth the trouble, but the GT4 uses a Drexler doesn't it?

[strokemycocktus]

These hubs would be a nice addition to the brake/spindle swap. I wonder how much do these F8x spindles change the stock e92 camber, and what benefits would we see after swapping the hubs (some weight savings, maybe slightly more aggressive offset like mentioned above, but anything else?)

We could ask our friend who has retrofitted the brakes with spindles to post his current alignment specs

[wyatth]

Still curious what benefit the hubs would add.


What are you all seeing M2/3/4 blue calipers sell for F/R? I don’t mind buying new rotors and pads, and I found some spindles for a fair price. Just not sure what I should expect to pay for 4 used/clean calipers.

[strokemycocktus]

Originally Posted by wyatth

Still curious what benefit the hubs would add.

I think weight savings and that's all. I have calculated the total weight difference using realoem and swapping the hubs and rotor shields along with the brakes and spindles you get only about 1kg more unsprung mass per front wheel with bigger brakes. Using e92 hubs and shields will make the setup heavier.

[wyatth]

Touché. No doubt they’re nice pieces. Not sure I can justify $600 for 1lb if there’s no other objective benefit. Again, if stock units are wearing out it’s another story.

Hm wonder what the weight gain would be by adding the brakes without the hubs. +3-5lb per corner? Calipers should be less, so I think it’s just the bigger rotors.

[strokemycocktus]

Per realoem calipers are heavier as well. Pads weigh about the same IIRC.

[Zero Signal]

Bumping and old thread. What about front and rear shocks/struts, anyone try it yet. A bunch of used f8x low mileage shocks/struts popping up cheap.

[gmx]

What are the requirements of each?

Ie
F8X uprights:
- lug spacing different for brakes, need bracket or F8x brakes, or a BBK/alternative bracket for F8x(?). E9x Damper fits?

Originally Posted by Richbot

I can think of a dozen reasons why it'd be insane to bother trying, but I'd love to see somebody try

Retrofitting the F8x e-diff might almost be worth the trouble, but the GT4 uses a Drexler doesn't it?

I'm going to guess SRO/GT4 active diffs are either not allowed/banned or the active e-diff isn't reliable for endurance races over a season.

[Richbot]

Rear hub is also backwards-compatible and saves half a pound per side. Updated above

[BayE30]

Rear F80 brake setup (calipers and rotors) is plug and play for e9xm3 as well rite?

[Richbot]

That's why I put a link in there, there are some "yes buts" with the rear setup IIRC (pad swept area might be different, don't try to use aftermarket rear rotors with the F8x rear caliper, that kind of thing)

[MikeM5]

Originally Posted by wyatth

Still curious what benefit the hubs would add.

I think the weight savings were a happy discovery, but the main benefit (to me anyway) is upgrading to M14 hardware. I think M12 is undersized for the car and peace of mind on track is certainly a nice bonus. I think it's one of those upgrades that becomes a no brainer when bearings are due maintenance-wise.

[s0ldats]

i tried searching for more info on the e8x front upright swap and wasn't able to find any specifics outside of this thread. can someone point me in the right direction?