Quote:
Originally Posted by johnung
I've done several F30 brake upgrades. It can be confusing due to a variety of parts and confusing marketing terms by BMW. (BMW calls several things "M Sport" that are actually different parts!) That confusion extends to website parts descriptions and to the sales people at parts suppliers. If you just read a website or call a supplier you can be getting the wrong information from them. There are already several incorrect statements in this thread.
Below is my top down view of upgrading F30 brakes. F30's are consistent with mounting points so in most cases a caliper or rotor from a higher model (i.e. 335) can bolt on to lower model (i.e. 328). There are caveats.
OPTION #1: "370/345"
Will NOT fit under 17" road wheels. 18" wheels are a minimum.
FRONT:
370mm x 30mm rotor
4-piston Brembo Caliper.
Visually looks like two round flat surfaces on the front about the size of silver dollars. There are two more on the back adding up to 4 pistons.
Identified by "370/380" in raised lettering on the rear of the caliper casting. Originally these front calipers came in Blue in the M Sport option (S2HNA? on original 335 build list). They also come in red, orange or yellow in the M Performance brake kit.
Note: These same calipers are on M3/M4 with 380mm rotors. NO, you can't swap in M suspension components onto an F30 just to have 380mm rotors. Causes many documented problems.
NOTE: Both 4-piston Brembo calipers, the one that uses a 370mm rotor and the one that uses a 340mm rotor, both use exactly the same size front brake. Identical! Another reason why websites and brake pad part numbers can be confusing. Plus BMW and parts houses sometimes call both of them "M Sport", so that's not always a differentiator either!
REAR:
345mm x 24mm rotors
(requires minimum 18" road wheel)
Caveat: There are two different varieties of this size rotor. The one that you need is based strictly on which size rear parking brake came on your car. Most F30's have 185mm parking brakes which sit inside what is essentially a brake drum housed inside the rotor hat. This is why people may refer to a "larger rotor hat". Some F30's have smaller 160mm parking brakes and there are the same size rotors available with "smaller hats" to fit them.
NO, it's not cost effective to swap out hubs just to change parking brake size.
2-piston Brembo Caliper.
Visually looks like a single round flat surface on the front about the size of a silver dollar. There's a second one on the back adding up to 2 pistons.
Identified by being either blue, red, yellow or orange.
"345" pads are unique and are the largest F30 rear pad.
OPTION #2: "340/345"
Requires minimum 18" road wheels because the rear brakes won't fit under 17" wheels.
This is a combination of the rear calipers and rotors from Option #1 and the front calipers and rotors from Option #3. Most often occurs when someone with 335i stock brakes wants to do a partial, less costly upgrade. It is very effective in reducing the frontend dive when braking hard. With the stronger rear brakes the car tends to squat flat in a more controlled manner. Definitely recommend it as a noticeable upgrade.
Upgrading from 340 to 370 front brakes is not as noticeable because the calipers are essentially the same, pads are the same and only rotors are larger, while swept rotor size is same. It's mostly a looks upgrade.
OPTION #3: "340/330"
These are the standard brakes on the F30 335
Fits with 17" or larger road wheels.
FRONT:
340mm x 30mm rotor
4-piston Brembo Caliper.
Visually looks like two round flat surfaces on the front about the size of silver dollars. There are two more on the back adding up to 4 pistons.
Identified by "340" in raised lettering on the rear of the caliper casting. Originally these front calipers came on various F30 models in either grey or blue. On an original 335 build list they are identified by code P337A. At times BMW and parts sellers also call this "M Sport" adding to confusion.
REAR:
330mm x 20mm rotors
(requires minimum 17" road wheel)
Caveat: There are two different varieties of this size rotor. The one that you need is based strictly on which size rear parking brake came on your car. Most F30's have 185mm parking brakes which sit inside what is essentially a brake drum housed inside the rotor hat. This is why people may refer to a "larger rotor hat". Some F30's have smaller 160mm parking brakes and there are the same size rotors available with "smaller hats" to fit them.
NO, it's not cost effective to swap out hubs just to change parking brake size.
1-piston Caliper made by Bosch
I have only seen them in grey as the stock rear brakes for an F30 335. I guess it's possible they could be blue in a lower level car model but I can't verify that.
These do an excellent job when paired with the 340mm front brakes.
I hope that this helps for now. I have a ton more information that I can try to post when I have time over the next couple of days about brands and types of rotors and pads. Stainless lines. Painting or powder coating. Buying used parts,etc. Ask questions if u have any and I'll try to answer in later posts.
Hope this helps!
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Perhaps the best write up on the subject from
johnung.