[Norris83]

I upgraded my 2018 M550I brakes and now that I have a set of front calipers and rotors, I'm thinking of putting these on my wife's 2018 X3 Xdrive30i base model brakes.

The brakes off the m550i have the larger 374x36mm rotors than the M40i brakes 348x36mm.

[burgerkong]

I was thinking G01's were parts bin specials when comparing the X3M calipers to the M40i, then I realized while the rotor thickness was the same, similar (if not identical) offset, identical piston sizes/setup, the actual mounting ears on the knuckle was different. In fact, the entire knuckle and wheel hub/bearing were specific to ONLY the X3M.

Tldr, you may run into issues with the mounting ears. That being said, if it physically bolts on and the old rotor on the G01 is centered on the M550i calipers, it'll work. The piston sizes should be identical on the M550i calipers vs the M40i which means it'll work fine on the Xdrive30i as the M/C's are all the same.

Please update! Would love a bigger front rotor to soak up more heat.

[Norris83]

Got everything installed.
Disc sizes are
374x36mm Fronts
370x24mm rears

[burgerkong]

Originally Posted by Norris83

Got everything installed.
Disc sizes are
374x36mm Fronts
370x24mm rears

How does it feel? Basically plug and play/caliper bolts up with the M550i rotors?

[Norris83]

Originally Posted by burgerkong

How does it feel? Basically plug and play/caliper bolts up with the M550i rotors?

It's basically all plug and play. The car originally came with the stock none M brakes. I had upgraded the brakes soon after I bought the car because I had a set of stock brakes off my 2017 540i 348x30mm front rotors with 4 piston calipers and rears were 345x24mm. Those were a massive upgrade from oem.
Now with the new setup off the m550i brakes they feel really solid and very capable on highway. I didn't want to go too hard on them since the pads are brand new. I will give you another update in a week after the new pads are broken in. Attached are pictures of the brakes that I had from the 540i.
I re-used the rear calipers, just went with a different caliper carrier for the rears to accommodate the larger rear discs, but the new caliper carriers are blue lol. Fronts are directly off the m550i.

[vrships]

Originally Posted by Norris83

Got everything installed.
Disc sizes are
374x36mm Fronts
370x24mm rears

Is this the same front caliper as in x3 m40i?

If so, like you said, the rotor has a larger size but the caliper is bolted at the same locations, what difference will this make than OEM m40 brakes since the pads are still pressed at the same spots on the rotors?

[burgerkong]

Originally Posted by vrships

Is this the same front caliper as in x3 m40i?

If so, like you said, the rotor has a larger size but the caliper is bolted at the same locations, what difference will this make than OEM m40 brakes since the pads are still pressed at the same spots on the rotors?

Same piston sizes, but rotor diameter is bigger (M40i is 348mm in front). Braking force depends on several factors including rotor diameter (bigger = higher braking force).

[Norris83]

Originally Posted by vrships

Is this the same front caliper as in x3 m40i?

If so, like you said, the rotor has a larger size but the caliper is bolted at the same locations, what difference will this make than OEM m40 brakes since the pads are still pressed at the same spots on the rotors?

The larger the diameter rotors the force increases. Think of it this way, if you were to use a short torque wrench to loosen bolts vs a longer one. With a longer wrench it will be less effort to open it. Another factor is the bigger size rotors have a larger area which keeps temperatures lower.

[Norris83]

Originally Posted by burgerkong

Same piston sizes, but rotor diameter is bigger (M40i is 348mm in front). Braking force depends on several factors including rotor diameter (bigger = higher braking force).

You're absolutely right about the rotor size.

I think the pistons are slightly smaller on The M sport calipers with 348x36 rotors because it has different pads than the m sport calipers with 374x36 discs.

The calipers that use 374x36 discs and the larger calipers that use 395x36 discs use the same pads and identical in piston size.

[Adamantio]

Hi guys, I have recently updated my base system with a 348 mm front and 345 rear Msport but it doesn't satisfy me much.
Would a further upgrade to 374/370 be possible by just changing the disks? Or do you have to change something else?
Thanks

[Norris83]

Originally Posted by Adamantio

Hi guys, I have recently updated my base system with a 348 mm front and 345 rear Msport but it doesn't satisfy me much.
Would a further upgrade to 374/370 be possible by just changing the disks? Or do you have to change something else?
Thanks

The fronts you will need larger calipers. The rears it's just the caliper carriers to extend further out.

[Adamantio]

Originally Posted by Norris83

The fronts you will need larger calipers. The rears it's just the caliper carriers to extend further out.

Hi, So I didn't understand correctly, in order to be able to mount the 374/370 discs do I need the largest suitable calipers? Is there no way to fit them on 348/345 M calipers?

[Norris83]

Originally Posted by Adamantio

Hi, So I didn't understand correctly, in order to be able to mount the 374/370 discs do I need the largest suitable calipers? Is there no way to fit them on 348/345 M calipers?

If you currently have M sport brakes, blue calipers. The front you need calipers still but rears you just need caliper carriers that can accommodate 370x24mm discs.

The Front calipers are needed for 374x36mm diameter rotors from G11/G12/G20 or G30 which is what I got.

Calipers part numbers

34116891303 left
34116891304 right

Front disc part numbers
34116875283 left
34106875284 right

Pads part number 34116889586

Another option is you purchase the G30 M performance brake kit. It's even larger discs but you get red calipers. 34112289348 . You can also mount the larger calipers off the X3M or M850I it would fit 395x36mm discs but the downside is you need wheels that are 20" minimum to clear the calipers. I had issues with my m550i fitting my winters had to get new wheels and tires.

For the rears you only need the caliper carriers off of G05 x5 or X3M.

Part numbers for caliper carriers

34206891773

34206891774

Part numbers for rear discs 370x24,

34216860927

Pads are same as original 34216867175

[comber]

Originally Posted by Norris83

If you currently have M sport brakes, blue calipers. The front you need calipers still but rears you just need caliper carriers that can accommodate 370x24mm discs.

The Front calipers are needed for 374x36mm diameter rotors from G11/G12/G20 or G30 which is what I got.

Calipers part numbers

34116891303 left
34116891304 right

Front disc part numbers
34116875283 left
34106875284 right

Pads part number 34116889586

Another option is you purchase the G30 M performance brake kit. It's even larger discs but you get red calipers. 34112289348 . You can also mount the larger calipers off the X3M or M850I it would fit 395x36mm discs but the downside is you need wheels that are 20" minimum to clear the calipers. I had issues with my m550i fitting my winters had to get new wheels and tires.

For the rears you only need the caliper carriers off of G05 x5 or X3M.

Part numbers for caliper carriers

34206891773

34206891774

Part numbers for rear discs 370x24,

34216860927

Pads are same as original 34216867175

Thx for the info!

So...considering that I have 21" wheels, you mean that I could fit X4M rotors and calipers into my M40i without making any modification?

[Norris83]

Originally Posted by comber

Thx for the info!

So...considering that I have 21" wheels, you mean that I could fit X4M rotors and calipers into my M40i without making any modification?

Yes they would fit. The calipers fit perfectly, the rotors/discs retaining screws don't match but would still work front and rear. If you get rotors/discs from X5 the plain ones they fit perfectly even the set screws / retaining screws match up.

[comber]

Originally Posted by Norris83

Yes they would fit. The calipers fit perfectly, the rotors/discs retaining screws don't match but would still work front and rear. If you get rotors/discs from X5 the plain ones they fit perfectly even the set screws / retaining screws match up.

Thx!!

[Norris83]

Oem 19" wheels with winter tires. The brakes fill the wheels nicely!

[Sully57]

Originally Posted by Norris83

If you currently have M sport brakes, blue calipers. The front you need calipers still but rears you just need caliper carriers that can accommodate 370x24mm discs.

The Front calipers are needed for 374x36mm diameter rotors from G11/G12/G20 or G30 which is what I got.

Calipers part numbers

34116891303 left
34116891304 right

Front disc part numbers
34116875283 left
34106875284 right

Pads part number 34116889586

Another option is you purchase the G30 M performance brake kit. It's even larger discs but you get red calipers. 34112289348 . You can also mount the larger calipers off the X3M or M850I it would fit 395x36mm discs but the downside is you need wheels that are 20" minimum to clear the calipers. I had issues with my m550i fitting my winters had to get new wheels and tires.

For the rears you only need the caliper carriers off of G05 x5 or X3M.

Part numbers for caliper carriers

34206891773

34206891774

Part numbers for rear discs 370x24,

34216860927

Pads are same as original 34216867175

Hi Norris,


I have a g31 530d xDrive 2017. I have M sport blue callipers and 20inch wheels

I wanted to upgrade the front and rear brakes, but the backs first. I have been looking for calliper carriers on ebay. I found a left rear calliper with carrier of an x3. I’ve attached the link here. would this be the correct one? i’m just confused as you’ve mentioned I can fit x3m or x5 g05 carriers and the one i’ve attached here fits a g05 x5.

The link is here: https://www.ebay.co.uk/itm/144851154666?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=vviemK9fSPe&sssrc=2349624&ssuid=rsVDJKBg Rj-&var=&widget_ver=artemis&media=COPY

This is my first post/comment here.

[Norris83]

Originally Posted by Sully57

Hi Norris,


I have a g31 530d xDrive 2017. I have M sport blue callipers and 20inch wheels

I wanted to upgrade the front and rear brakes, but the backs first. I have been looking for calliper carriers on ebay. I found a left rear calliper with carrier of an x3. I’ve attached the link here. would this be the correct one? i’m just confused as you’ve mentioned I can fit x3m or x5 g05 carriers and the one i’ve attached here fits a g05 x5.

The link is here: https://www.ebay.co.uk/itm/144851154666?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=vviemK9fSPe&sssrc=2349624&ssuid=rsVDJKBg Rj-&var=&widget_ver=artemis&media=COPY

This is my first post/comment here.

If your 5 series has 345x24mm rear discs you will need these parts.

Rear caliper carrier

34206883005 $189 USD
34206883006 $189 USD

Rear discs

34216860927 $235USD for the pair.

New brake pads, same as original.

[Norris83]

Originally Posted by Sully57

Hi Norris,


I have a g31 530d xDrive 2017. I have M sport blue callipers and 20inch wheels

I wanted to upgrade the front and rear brakes, but the backs first. I have been looking for calliper carriers on ebay. I found a left rear calliper with carrier of an x3. I’ve attached the link here. would this be the correct one? i’m just confused as you’ve mentioned I can fit x3m or x5 g05 carriers and the one i’ve attached here fits a g05 x5.

The link is here: https://www.ebay.co.uk/itm/144851154666?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=vviemK9fSPe&sssrc=2349624&ssuid=rsVDJKBg Rj-&var=&widget_ver=artemis&media=COPY

This is my first post/comment here.

Refer to this thread for the 5 series. I did this upgrade to my 2018 M550I.

https://g30.bimmerpost.com/forums/sh....php?t=1817852

[keithguido]

Just curious about the difference on the road with the new brakes!

[Norris83]

Originally Posted by keithguido

Just curious about the difference on the road with the new brakes!

They’re incredibly solid especially with highway speeds.