[homanmaster]

I currently have a F30 N55 with the M Performance red brake upgrade. Im currently running Big Boost 3.3 FBO and making over 600whp. I want to know if a 17 inch rim will clear the rear M Performance brakes? The rear has 345mm rear rotors with the dual rear piston Brembo caliper.

[johnung]

Originally Posted by homanmaster

I currently have a F30 N55 with the M Performance red brake upgrade. Im currently running Big Boost 3.3 FBO and making over 600whp. I want to know if a 17 inch rim will clear the rear M Performance brakes? The rear has 345mm rear rotors with the dual rear piston Brembo caliper.

Most 17" wheels will not clear the front 370mm brakes or the rear 345mm brakes. So largest that will clear are F340mm/R330mm.

BMW 400M 18" wheels are readily available used sets for $500-$600 in great condition

[Desertnate]

If the Performance Brake calipers are the same size or larger than the blue M Sport ones, I don't see how they could fit.

I'm running 18" wheels for my winter set up and there is only about .25~.5" of clearance between the calipers and the wheels. Not even enough room to get a wheel brush though to clean the wheels. I have the blue M Sport Brakes with the 370mm/345mm rotors.

[homanmaster]

I wish I knew someone with wide 17 inch rims to see if an APEX arc8 17x9 would rear the rears.

[draggy]

17's can fit - it just depends on the specific wheel. Take a look at post #6 here: https://f30.bimmerpost.com/forums/sh....php?t=1552773

[Nseruame]

Originally Posted by homanmaster

I currently have a F30 N55 with the M Performance red brake upgrade. Im currently running Big Boost 3.3 FBO and making over 600whp. I want to know if a 17 inch rim will clear the rear M Performance brakes? The rear has 345mm rear rotors with the dual rear piston Brembo caliper.

Sorry this is a little off topic to the thread but by reading your post you might be of a little more help. I've been considering purchasing the M performance brake kit but I want to hear if there are noticeable gains. I've been reading through the forums regarding these all morning and they're mostly filled with people arguing about what color looks better (must be 328 owners). From the power upgrades you said you have on your car I figured you'd be able to give me a good answer on if these brakes are worth the purchase over the stock basic brakes I have in my 435i.

[johnung]

Originally Posted by Desertnate

If the Performance Brake calipers are the same size or larger than the blue M Sport ones, I don't see how they could fit.

I'm running 18" wheels for my winter set up and there is only about .25~.5" of clearance between the calipers and the wheels. Not even enough room to get a wheel brush though to clean the wheels. I have the blue M Sport Brakes with the 370mm/345mm rotors.

M Performance brake calipers are exactly the same calipers that you have: Front 370mm and Rear 345mm. They are just painted red, orange or yellow.

[johnung]

Originally Posted by Nseruame

Sorry this is a little off topic to the thread but by reading your post you might be of a little more help. I've been considering purchasing the M performance brake kit but I want to hear if there are noticeable gains. I've been reading through the forums regarding these all morning and they're mostly filled with people arguing about what color looks better (must be 328 owners). From the power upgrades you said you have on your car I figured you'd be able to give me a good answer on if these brakes are worth the purchase over the stock basic brakes I have in my 435i.

I have done several F3x brake caliper upgrades. I started with the same Grey calipers that you have on your 435i. You have Front 4-piston Brembos over 340mm x 30mm rotors. And Rear 1-piston Bosch over 330mm x 20mm rotors.

When you slam on your brakes the car will nosedive and be more difficult to control. This is because of the weaker rear brakes.

So the next logical step is to upgrade the rear calipers to 2-piston Brembos over 345mm x 24mm rotors. When you slam on those brakes, the car will squat much more controllably.

The next step up is to upgrade the Front 340mm to Front 370mm calipers. The 370's are stretched out castings of the smaller calipers. Functionally they are exactly the same with the same sized pistons and even the same sized brake pads, but physically they are different sizes so the calipers are not interchangeable.

The 370's have larger rotors so they look more impressive behind the road wheels. More bling.

On the street, it might be difficult to notice whether a car has front 340 or 370 brakes. Performance is the same. Under repeated braking like on a track, the 370 rotors have more mass so they are less susceptible to overheating/ brake fade.

The F3x M Performance Brake Kit essentially does both of these caliper upgrades at once so the result is Front 370/ Rear 345.

The downsides of the MPBK are the no better than average brake pads, and the dimpled/slotted front rotors. (Rear rotors don't come with the MPBK because rotors need to be purchased to fit the handbrake that came on the car, either the 160mm or 185mm.)

I personally wouldn't install the MPBK without also upgrading the pads and rotors as per my comments below.

Those are the only differences that you will notice by changing calipers. But no one has to change calipers to be able to improve their braking.

The simplest most effective way to improve braking performance is to replace the very average BMW stock brake pads with Hawk 5.0 brake pads. They have the best bite for the street and will make a huge difference.

The next way to improve street braking is to upgrade plain rotors to full crossdrilled rotors. Crossdrilled have the best bite and they have the best performance in the rain because water can't trap between the pad and rotor surfaces. I can't tell a braking difference in the pouring rain. I have to tell myself to slow down anyway for safety.

I highly recommend StopTech Crossdrilled rotors. They have an internal directional vane designed to optimize air cooling. They pull air through the rotor better to prevent brake fade. They come in separate left and right part numbers.

Avoid dimpled and slotted rotors for the street. They are noisy and tear up pads. BMW designed them for bling, not for brake performance.

When you are doing a brake job or replacing brake fluid (every two years for safety) take the opportunity to upgrade your stock rubber brake hoses for stainless steel brake lines. Gets rid of mush and provides a much more solid brake pedal feel. StopTech's are only $110/set.

I have part numbers if you need them.

Hope this helps!

[Expert@ApexWheels]

Originally Posted by homanmaster

I wish I knew someone with wide 17 inch rims to see if an APEX arc8 17x9 would rear the rears.

We've tested a 17x8.5 ET40 ARC-8 on a car with the 345mm rear brakes (2 series). The fitment is super tight and some rocks caused rubbing between the caliper and the wheel barrel. It technically fits, but is really tight on our flow formed ARC-8s.


Jakes 230i Msport with ARC-8 17x8.5 ET40 in Satin black by ApexRaceParts, on Flickr


Jakes 230i Msport with ARC-8 17x8.5 ET40 in Satin black by ApexRaceParts, on Flickr

No 17" wheels will clear the 370mm front brakes.

-Tom

[CajunBMW]

Originally Posted by johnung

I have done several F3x brake caliper upgrades. I started with the same Grey calipers that you have on your 435i. You have Front 4-piston Brembos over 340mm x 30mm rotors. And Rear 1-piston Bosch over 330mm x 20mm rotors.

When you slam on your brakes the car will nosedive and be more difficult to control. This is because of the weaker rear brakes.

So the next logical step is to upgrade the rear calipers to 2-piston Brembos over 345mm x 24mm rotors. When you slam on those brakes, the car will squat much more controllably.

The next step up is to upgrade the Front 340mm to Front 370mm calipers. The 370's are stretched out castings of the smaller calipers. Functionally they are exactly the same with the same sized pistons and even the same sized brake pads, but physically they are different sizes so the calipers are not interchangeable.

The 370's have larger rotors so they look more impressive behind the road wheels. More bling.

On the street, it might be difficult to notice whether a car has front 340 or 370 brakes. Performance is the same. Under repeated braking like on a track, the 370 rotors have more mass so they are less susceptible to overheating/ brake fade.

The F3x M Performance Brake Kit essentially does both of these caliper upgrades at once so the result is Front 370/ Rear 345.

The downsides of the MPBK are the no better than average brake pads, and the dimpled/slotted front rotors. (Rear rotors don't come with the MPBK because rotors need to be purchased to fit the handbrake that came on the car, either the 160mm or 185mm.)

I personally wouldn't install the MPBK without also upgrading the pads and rotors as per my comments below.

Those are the only differences that you will notice by changing calipers. But no one has to change calipers to be able to improve their braking.

The simplest most effective way to improve braking performance is to replace the very average BMW stock brake pads with Hawk 5.0 brake pads. They have the best bite for the street and will make a huge difference.

The next way to improve street braking is to upgrade plain rotors to full crossdrilled rotors. Crossdrilled have the best bite and they have the best performance in the rain because water can't trap between the pad and rotor surfaces. I can't tell a braking difference in the pouring rain. I have to tell myself to slow down anyway for safety.

I highly recommend StopTech Crossdrilled rotors. They have an internal directional vane designed to optimize air cooling. They pull air through the rotor better to prevent brake fade. They come in separate left and right part numbers.

Avoid dimpled and slotted rotors for the street. They are noisy and tear up pads. BMW designed them for bling, not for brake performance.

When you are doing a brake job or replacing brake fluid (every two years for safety) take the opportunity to upgrade your stock rubber brake hoses for stainless steel brake lines. Gets rid of mush and provides a much more solid brake pedal feel. StopTech's are only $110/set.

I have part numbers if you need them.

Hope this helps!

Hi johnung ,

Thanks for the great info. You have given a lot of wonderful info on a bunch of threads I have followed. Based on your recommendations, I have a question for you. I have a 2018 340 and was thinking of upgrading brakes as per your suggestions. I have the normal grey brakes that came with my car. They work fine and I realize part of the upgrade is for the looks, but I do like to let the car run on fun twisty rural roads and other places. Would be fun to track it, but am too busy unfortunately. I had the mppsk added right before the pandemic hit and love what it has brought to the car (plus the warranty, since the major parts of the car are still under warranty).

At present I don't have the time to do anything myself (between kids and pandemic work), so if I started with the M Performance Brake Kit and had it installed by the dealer for example, would I be happy with it to drive around on for say a year. I don't want to be wishing I kept my grey brakes. I have followed the many threads on this topic and understand some say they are noisy and that it will chew up pads, but I would then plan when I had time to do new pads and rotors and brake lines (as you point out above, maybe my indie shop could do this). My 340 is my daily driver but I do like to take spirited drives around the multiple states here in the south. Plus who doesn't like the car to look good.

Thanks in advance for your help.

[johnung]

Originally Posted by CajunBMW

Hi johnung ,

Thanks for the great info. You have given a lot of wonderful info on a bunch of threads I have followed. Based on your recommendations, I have a question for you. I have a 2018 340 and was thinking of upgrading brakes as per your suggestions. I have the normal grey brakes that came with my car. They work fine and I realize part of the upgrade is for the looks, but I do like to let the car run on fun twisty rural roads and other places. Would be fun to track it, but am too busy unfortunately. I had the mppsk added right before the pandemic hit and love what it has brought to the car (plus the warranty, since the major parts of the car are still under warranty).

At present I don't have the time to do anything myself (between kids and pandemic work), so if I started with the M Performance Brake Kit and had it installed by the dealer for example, would I be happy with it to drive around on for say a year. I don't want to be wishing I kept my grey brakes. I have followed the many threads on this topic and understand some say they are noisy and that it will chew up pads, but I would then plan when I had time to do new pads and rotors and brake lines (as you point out above, maybe my indie shop could do this). My 340 is my daily driver but I do like to take spirited drives around the multiple states here in the south. Plus who doesn't like the car to look good.

Thanks in advance for your help.

Ah, it must be crawfish season right about now! I married a girl from New Orleans!

Thanks! Glad that you found my stuff helpful. Great questions! If you installed the M Performance Brake Kit you would get the caliper performance gains that I mentioned previously over your stock Front 340mm/Rear 330mm.

So the rear 345mm will cause the car to squat more controllably, rather than nose dive like with the 340/330 stock caliper combination. And the front 370mm brakes will be more resistant to brake fade and look more substantial.

The most noticeable downside of the MPBK is the noise from the dimpled/slotted rotors. Some guys barely notice it and others, it drives them bat sh*t crazy. The noise is most noticeable when driving say in the left lane next to a concrete median barrier because the noise reflects right back at the driver.

The best place to buy the MPBK is GetBMWParts website for $1,895. It's actually a BMW dealer in Maryland who sells Genuine BMW parts at a discount. The rear rotors (345x24) need to be purchased separately and you would need the newer ones that accommodate the rear 185mm handbrake that's on your car.

I would also install stainless steel brake lines at the same time. They get rid of brake mush and create a much more solid brake pedal feel. Additional labor cost should be zero. StopTech SS lines are only about $110/set.

I personally wouldn't pay dealer labor prices. You still get the BMW M Performance parts warranty if it's installed by an independent BMW mechanic. Mine has all experienced factory trained mechanics and charges me $120/hour whenever I bring them parts. Found them on BimmerShops website. They would charge me about $450-$500 labor for a complete brake replacement like the MPBK.

I mentioned previously that I'm not a fan of the set of four MPBK pads which are no better than average, or the pair of front 370mm dimpled/slotted rotors that come with the MPBK which provide no more than a tiny improvement over plain rotors.

Anyone who upgrades to the MPBK is going to feel a brake improvement and is unlikely to realize that they could have had even more improvement. I view installing the MPBK as is, as paying a high price for what you are getting- excellent brand new calipers, but only average pads and rotors.

Compare that to purchasing used blue M Sport Calipers in the same F370/R345 sizes for about $1,100 in excellent condition. Of course it's more hassle to find used calipers. And the brand new MPBK calipers are $1,895 but the new pads and rotors can be sold to reduce that cost.

Once the MPBK pads and rotors are installed, they become used parts and their value drops. So it wouldn't be cost effective to change them out for better pads & rotors for 1-3 years, depending on miles driven.

So the most effective way to end up with highest performance street braking result, at the lowest cost, is to purchase the MPBK to get the brand new 370/345 calipers, the StopTech stainless steel brake lines, Hawk 5.0 pads and four StopTech Crossdrilled rotors.

That saves the money that would have been spent on rear dimpled/slotted 345mm rotors. And since the MPBK front rotors and four pads are brand new, they can be sold on the used market for more money than if they had been installed. Also the original calipers can be sold on the used market. Front 340mm Brembos typically sell between $350-$500/pair, and the rear Bosch 330 calipers for about $100-$200/pair along with throwing in the original 330mm rotors.

That's my take on the MP Brake Kit and the options available. I have more details like part numbers if needed.

Hope this helps!

[CajunBMW]

Originally Posted by johnung

Ah, it must be crawfish season right about now! I married a girl from New Orleans!

Thanks! Glad that you found my stuff helpful. Great questions! If you installed the M Performance Brake Kit you would get the caliper performance gains that I mentioned previously over your stock Front 340mm/Rear 330mm.

So the rear 345mm will cause the car to squat more controllably, rather than nose dive like with the 340/330 stock caliper combination. And the front 370mm brakes will be more resistant to brake fade and look more substantial.

The most noticeable downside of the MPBK is the noise from the dimpled/slotted rotors. Some guys barely notice it and others, it drives them bat sh*t crazy. The noise is most noticeable when driving say in the left lane next to a concrete median barrier because the noise reflects right back at the driver.

The best place to buy the MPBK is GetBMWParts website for $1,895. It's actually a BMW dealer in Maryland who sells Genuine BMW parts at a discount. The rear rotors (345x24) need to be purchased separately and you would need the newer ones that accommodate the rear 185mm handbrake that's on your car.

I would also install stainless steel brake lines at the same time. They get rid of brake mush and create a much more solid brake pedal feel. Additional labor cost should be zero. StopTech SS lines are only about $110/set.

I personally wouldn't pay dealer labor prices. You still get the BMW M Performance parts warranty if it's installed by an independent BMW mechanic. Mine has all experienced factory trained mechanics and charges me $120/hour whenever I bring them parts. Found them on BimmerShops website. They would charge me about $450-$500 labor for a complete brake replacement like the MPBK.

I mentioned previously that I'm not a fan of the set of four MPBK pads which are no better than average, or the pair of front 370mm dimpled/slotted rotors that come with the MPBK which provide no more than a tiny improvement over plain rotors.

Anyone who upgrades to the MPBK is going to feel a brake improvement and is unlikely to realize that they could have had even more improvement. I view installing the MPBK as is, as paying a high price for what you are getting- excellent brand new calipers, but only average pads and rotors.

Compare that to purchasing used blue M Sport Calipers in the same F370/R345 sizes for about $1,100 in excellent condition. Of course it's more hassle to find used calipers. And the brand new MPBK calipers are $1,895 but the new pads and rotors can be sold to reduce that cost.

Once the MPBK pads and rotors are installed, they become used parts and their value drops. So it wouldn't be cost effective to change them out for better pads & rotors for 1-3 years, depending on miles driven.

So the most effective way to end up with highest performance street braking result, at the lowest cost, is to purchase the MPBK to get the brand new 370/345 calipers, the StopTech stainless steel brake lines, Hawk 5.0 pads and four StopTech Crossdrilled rotors.

That saves the money that would have been spent on rear dimpled/slotted 345mm rotors. And since the MPBK front rotors and four pads are brand new, they can be sold on the used market for more money than if they had been installed. Also the original calipers can be sold on the used market. Front 340mm Brembos typically sell between $350-$500/pair, and the rear Bosch 330 calipers for about $100-$200/pair along with throwing in the original 330mm rotors.

That's my take on the MP Brake Kit and the options available. I have more details like part numbers if needed.

Hope this helps!

Thank you for the advice. That is perfect.

Yes it is getting close to crawfish season. The ice storm and unseasonably and record cold, delayed some things. I'm hoping they don't call them mudbugs for nothing, as they may have needed that mud to protect them from the crazy cold. We are definitely looking forward to seasoned crawfish and all of the spring festivals.

I'm in New Orleans now for my daughter's soccer games. Always a fun trip.

Cheers and thanks.

[homanmaster]

Originally Posted by Expert@ApexRaceParts

We've tested a 17x8.5 ET40 ARC-8 on a car with the 345mm rear brakes (2 series). The fitment is super tight and some rocks caused rubbing between the caliper and the wheel barrel. It technically fits, but is really tight on our flow formed ARC-8s.


Jakes 230i Msport with ARC-8 17x8.5 ET40 in Satin black by ApexRaceParts, on Flickr


Jakes 230i Msport with ARC-8 17x8.5 ET40 in Satin black by ApexRaceParts, on Flickr

No 17" wheels will clear the 370mm front brakes.

-Tom

Hey do you know what the backspacing is on that wheel setup for the rear?

[jjjccc]

im using 17x9" ET30 Matte Bronze APEX ARC-8 with non m sport brakes in rear(gray color). i want to upgrade to the red m performance rear brakes rotors pads calipers(345x24). i have lots of room rt now from caliper to wheel in rear. but im not sure if the rear m performance calipers will be too close, anyone know if this will work? i think the et30 means my wheels backspace is 30.

[johnung]

Originally Posted by jjjccc

im using 17x9" ET30 Matte Bronze APEX ARC-8 with non m sport brakes in rear(gray color). i want to upgrade to the red m performance rear brakes rotors pads calipers(345x24). i have lots of room rt now from caliper to wheel in rear. but im not sure if the rear m performance calipers will be too close, anyone know if this will work? i think the et30 means my wheels backspace is 30.

Aftermarket wheels have various wheel barrel shapes and sizes so no one can give a blanket statement that say an 18" wheel will fit and a 17" wheel will not. You could probably find an 18" wheel that wouldn't fit and a 17" that would fit.

It's not possible to eyeball it or to guess based on rotor diameter. Wheels that don't fit can clear rotors, but then it's the body and shape of the caliper itself that hits the inside barrel of the wheel.

BremboGT calipers actually provide a pdf on their website. It's a printable template that outlines their caliper in reference to the centerpoint of the hub. It can be placed inside the wheel when it is off the car to see if it hits.

This is how I learned that BremboGT calipers that had a smaller rotor diameter than my M Sport calipers, definitely would not fit under my BMW 18" 400 M wheels.

Oh, also Brembo has a recommended distance to maintain between the caliper and the barrel of the wheel. (I don't recall the number) That is because if you cut it too close and there's only a very tiny gap between caliper and spinning road wheel, road debris can potentially get trapped and destroy the aluminum caliper.

APEX makes a design effort to fit brake calipers under their wheels. They would be the ones to ask about BMW caliper fitment with your APEX 17" wheels. They probably have documented it already.

Or find someone with an F3x with the caliper that you wish to get and ask if you can test fit your APEX 17" on their car. The currency for such requests used to be a 6-pack. With inflation perhaps it's a 12-pack now!

ET30 is the offset that the wheel has been designed with. Since it's a positive offset it means that if you take the imaginary centerline created by the hubs mating surface with the wheel, the actual center of the wheel is offset or pushed into the wheel well by 30mm.

When comparing setups it's important to compare offsets. For example my 18x8.0" BMW wheels have an ET34. If I replaced them with another 18x8.0" wheel that was an ET30, that would mean that the outer rim of the wheel would actual stick further out of the wheel well by 4mm more than my stock wheel. If I replaced it with an 18x8.0" wheel that had an offset of ET40, that would mean that the outer rim of the new wheel would actually be 6mm further into the wheel well.

Now wheel width is also a big factor. If I changed from 8.0" wide wheels to 9.0" wide wheels, that would mean that just from wheel width alone (ignoring offset for the moment), the new wheel rim would stick out by 1/2" and stick in by 1/2", compared to my stock wheel.

Don't be quick to think that the widest wheel is better. It can cause fitment problems. It can also look stupid and be stupid with a tire that's too stretched to fit on to provide curb protection to the expensive wheel.

1/2" equals 12.7mm. So if someone changes both the wheel width and the offset (especially reducing the offset) they can quickly find themselves in trouble with wheels that protrude way out of the wheel well. You often hear of guys installing spacers to adjust how "flush" a new wheel/tire looks. Well that only works if the wheel sticks into the wheel well too much. If it sticks out too much, then they're screwed!

Tire diameter, tire width and tire tread width are also factors not discussed here.

Read posts by Alohasurftoad the guru on wheels/tires.

Hope this helps!

[jjjccc]

boy thats alot of factoring in things to tell. i cant give someone the wheel i have to drive.
hmm.. i do have email out to apex but they dont seem to understand what im asking. they told me to begin with that the m front calipers wont clear and im fine w that. however the rear m calipers surely look like they would as i have sooo much space between rear gray caliper and backside of wheel.
does 30 offset look promising even tho i have 9" width??
update - apex responded with better understanding. it will but can cause scratchin so thats out. ;-(

ok so..everywhere says more offset/less caliper clearance. i dont see how thats possible, bein as more is further away from hub and suspension. but the 17x9 barrel may still scratch

[_baz]

Was running 17" faces stepped up to 19"

The face caught the calliper at ET20 (10J) so had to use a 5mm spacer and of course the tyres are stretched 235/35 iirc

All depends on the style of the wheel though as people have mentioned

[Ennoch]

Originally Posted by johnung

Oh, also Brembo has a recommended distance to maintain between the caliper and the barrel of the wheel. (I don't recall the number) That is because if you cut it too close and there's only a very tiny gap between caliper and spinning road wheel, road debris can potentially get trapped and destroy the aluminum caliper.

It's ironic that in all the years of having less than 3mm between the winter rims and AP calipers on the Impreza I've not had any issues with stones or debris getting stuck despite being on gravel and grit covered roads a lot, yet the other day I got a stone stuck between the 370mm front brakes and front 403M which left a nice gouge on the inner rim. I'd be more worried about the rim than the caliper, but the advice still stands.

[jjjccc]

apex says any 17 inch is goin to be too close w/ rear m performance calipers(chance of something gettin in between causing those scratches inside), on inside of the barrel of the rim even if using spacer the inner barrel diameter clearance is the problem

[snipagang]

Originally Posted by johnung

Most 17" wheels will not clear the front 370mm brakes or the rear 345mm brakes. So largest that will clear are F340mm/R330mm.

BMW 400M 18" wheels are readily available used sets for $500-$600 in great condition

where could we find something like this for sale?

[jjjccc]

Originally Posted by snipagang

where could we find something like this for sale?

apex has good ones. even their 17x9 "s will work with 330rear 340front

[johnung]

Originally Posted by snipagang

where could we find something like this for sale?

You'll find used BMW 400M wheels advertised for sale on Bimmerpost regional areas and on many BMW Facebook sites. Wheels are too heavy/expensive to pack and ship so you need to find a seller within driving distance. Often they'll meet you halfway. I've bought/sold various parts in Wawa parking lots.

Often guys have used parts in the garage and just haven't gotten around to advertising them for sale. I myself have a Wagner intercooler and several other parts that I just haven't gotten around to selling yet. So also advertise that you are looking to buy something. WTB ads often get responses from guys who want to get rid of something taking up space in the garage. Good luck!