[F87source]

Credit: 034Motorsport https://www.034motorsport.com/replac...-m2-m3-m4.html



Credit: 034Motorsport https://www.034motorsport.com/replac...-m2-m3-m4.html



Introduction:

In this product review I will be examining the 034Motorsport Front and Ring Replacement set for the BMW F8X M2, M3, and M4 (with the blue iron brakes) (I also have an extremely in depth review on the entire front and rear rotor set from 034Motorsport where I delve into the technical aspects of these rotors in a more detailed manner - more so than I will be doing here since this just focuses on the replacement rings themselves rather than the sheer technology these rotors possess, and if you want to read that review here is a link: https://f87.bimmerpost.com/forums/sh....php?t=2049119).
I will also go over the included hardware, discuss the bobbin system and how they allow the rotors to truly float in closer detail, explain the process in replacing the rotor rings, and I will of course show these replacement rotors and the included hardware in a bunch of high resolution photos.


If you want to purchase these replacement rotor rings here are some links (they are not affiliate links so I make no money if you use them or not):

034Motorsport:
Front: https://www.034motorsport.com/replac...-m2-m3-m4.html

Rear: https://www.034motorsport.com/replac...-m2-m3-m4.html



FCP Euro:

- I recommend purchasing these rotor rings through FCP Euro because you will get a lifetime warranty if you do so, this means you can burn through as many rotor rings as you’d like and replace them for essentially free.

Front:
https://www.fcpeuro.com/products/bmw...t-034-304-1009

Rear: https://www.fcpeuro.com/products/bmw...t-034-304-2009

Disclaimer:

Damage/Injury Disclaimer: Any information, guidance, technical advice, coding advice, tuning advice, datalogging advice, installation instruction, calculation, experiment, safety information, or product installation demonstrated in my reviews is to be consumed and or done at your own risk. I will not be responsible for personal injuries, injuries to others or any living being, or any damage to your car, or any property damage.

Monetary disclaimer: I do not make commission, or profits or any kind of monetary gain from the sale of the 034Motorsport Replacement Rotor Ring Set (Front and Rear) for the BMW F8X M2, M3, M4 (with blue iron brakes).


Sponsorship disclaimer: The way my reviews work is that I determine what product that I want to buy and actually use on my own car, and during this process the product that I end up choosing is what I believe is the best option on the market. I then reach out to the company offering the product and ask them if they would be willing to sponsor me in a review, if the answer is yes then I write a review, if the answer is no I would end up buying the product (sometimes at a later date) but I wouldn’t complete a detailed review about it (I might write something, but not to the same extent as my standard reviews). But the critical thing is that I reach out for a sponsorship and not the other way around, this means that the products I am reviewing are actually things I believe in and would use on my own car. This also means that I am not being paid to review something I do not care about. Would I do a review if a sponsor reached out to me? The answer would depend on if I believed in the product, and I would make it clear in my review if this were the case. But at the time of writing this review, such an interaction has not occurred yet.


Time of writing disclaimer: everything I am writing about in this review is described at the time of writing and may not be updated in the future, so there is a potential that things are no longer accurate in my comparisons as parts are changed and upgraded as time passes.


Bias and comparison disclaimer: Throughout this review I will attempt to be as unbiased as possible while drawing comparisons to other products.


Mistakes and Inaccuracies Disclaimer: Throughout my review I will try to be as factually accurate as possible, but there are always chances that I make mistakes and write things that are incorrect/false. If this is the case please point it out to me and if indeed it is true that I am incorrect, I will correct these mistakes and apologize for them. Afterall I am only human, so mistakes can and will inevitably happen.


Subjective Disclaimer: Please note, these reviews are also written in my own opinion, so when I am comparing different products to determine what I see as the best, there are many factors that I go through to form this opinion. Obviously there will be disagreements between people, so I will do my best to objectively determine what I deem to be the best, but at the end of the day it is still just my own opinion whether it be right or wrong. Take whatever I say in my reviews with a grain of salt.


Information Disclaimer: I read a lot of material over the years just out of sheer interest or to make these reviews. I also accumulated a lot of knowledge over my many years of education that are really relevant to cars (Physics, Chemistry, and Mathematics). That being said, my reviews are mostly based on this accumulated knowledge and I cannot always cite these sources due to the original source material possibly being lost to time, or there being so much knowledge compiled to make a single point. So, when possible I will cite my source(s) (for example data on tensile strength of a metal, or peer reviewed research). There are cases when I get information from blog posts, youtube videos, or forum posts I may not cite it, because I go through a lot of these sources only to use the gained knowledge in a small section of my review and it is not feasible to list them all. So pretty much what I am trying to say is I am not citing “common knowledge” - I will cite peer reviewed research and photos though (if applicable or used), or really explicit user experiences (if applicable or used).



Image Credits:

Images and videos used in this review are all property of their rightful owners as credited below each image, I am just using them for the purpose of this review but if you (the owner of the image) would like them removed please let me know via pm. Otherwise thanks to the respective image owners (I made sure to credit your online name and link where I found the photo) of the photos, without you this review would be so much more bland.



Review Disclaimer:

First and foremost I would like to thank 034Motorsport and Sean over ar 034Motorsport for agreeing to sponsor me for this review. Despite this I will remain as unbiased as possible during the review. Please note, the dynamics of this relationship was that I reached out for a sponsorship review and not the other way around. This should demonstrate how I truly feel about these replacement rings - in the sense that I truly believe it is an excellent product and one of the best offerings on the market. In fact I actually have the 034Motorsport front and rear rotors installed on my own m2 as of now, and I really love their looks, their ability to clear pad build up, and I am certain I will love their ability to float and vent extra air when I take the car to the track. So in essence I love their rotors so much that I would love to run these exact rotors even after they have worn out. So I requested a set of replacement rings so I could review them and further highlight the technical aspects of these rotors and showcase their future serviceability when they do wear out. Again If you would like to read my review on the rotors themselves here is a link: https://f87.bimmerpost.com/forums/sh....php?t=2049119



Why?:

To begin this review let's address the question “why would anyone want to replace their rotor friction rings after they have worn out, why not buy new rotors?”.

The answer to this question is quite simple really:

1) Lower total cost: Replacing the rotor rings alone is significantly cheaper than replacing the entire rotors. For instance, currently 034Motorsport charges $1,385.00 for their complete front rotor set on the F8X BMW M2,M3, and M4 and the front rotor rings alone are $693.00, this is $692.00 in savings and is essentially 50% cheaper. The complete rear rotor set cost $1,468.00 and the rear rotors rings alone are $881.00 which equates to a savings of $587.00 or ~40%. So if you replace the friction rings by themselves you’ll be saving yourself money. Additionally a nice thing to note is that they price the front replacement friction rings lower than the rear replacement friction rings, this generally is a nice thing to have since you will typically go through 2 or more sets of front rotors for each set of rear rotors.

This lower total cost also means that you will save on import fees (duty and taxes) if you are shipping it to outside of the USA (and trust me, those duties and taxes can get pricey - especially if you have Fedex or UPS clear the shipment for you and have to pay their insane brokerage fees which is multiple times more expensive than the taxes and duties combined).


2) More purchasing options: Being able to replace just the friction rings by themselves and not having to buy the entire rotor also opens you up to being able to buy from many different vendors - instead of being restricted to those that offer lifetime warranty. This means you can now look for vendors that are: having sales, offer rewards points, have free shipping, are local to you etc. You can even look for used rotors on the forums from users selling their cars. Then when it is time to replace the rotor rings you can buy these rings from vendors with lifetime warranty like FCP Euro, and now you will be able to have lifetime replacements and capitalize on the deal you might be able to secure beforehand.


3) Lower shipping weight: purchasing just the friction rings alone results in lower shipping weight saving you money on shipping, and this also makes the lifetime replacement warranty cheaper to utilize as well.



Unboxing:

Next let’s take a look at some unboxing images:


Credit: F87Source



Credit: F87Source



Credit: F87Source



Credit: F87Source



Credit: F87Source


So let’s recap the images. The 034Motorsport rotors come packaged in pairs, the 2 front rotors are shipped together in a large outer cardboard box, and the 2 rear rotors are shipped together in a large outer cardboard box as well - as shown in the first image. Contrasting this to the complete rotors, these boxes are about 1/4 the size (in terms of height) and significantly lighter. Within these outer boxes each rotor is packaged separately with their mounting hardware in smaller cardboard boxes - kind of like pizza boxes (images 2-4). So you get 2 large outer boxes, each of them contain 2 smaller boxes, each of these smaller boxes contain 1 rotor and mounting hardware.


Overall packaging was fine, despite being shipped from California to Canada my rotor rings arrived intact and undamaged, the outer boxes did show some signs of damage (typical carrier negligence) but the inner boxes were perfect - so the packaging did its job to protect the rotor rings. The inner boxes also did a great job protecting the rotors and kept them in place with the cardboard insert, so they were not damaged during shipping. Overall no complaints with packaging.




Rotors:

Next let's take a look at the friction rings and quickly recap the technology used in these rotors:


Credit: F87Source



Credit: F87Source



Credit: F87Source



Credit: F87Source



Credit: F87Source



Credit: F87Source


The friction rings here are identical to the ones that come on the full set of rotors, the fronts are the same 72 vane design that I described in my full review - and have 48 full vanes with every second vane being split to form 72 total vanes. The rear rotors have 48 full vanes.

Each rotor was designed with directionally curved internal vanes to act as a centrifugal air pump and sucks air from the center and expels it to the outside in order to cool the rotor. These rotors also feature “J-slots” on the face of the rotor which enables them: to expel pad off-gassing to resist fade, scrape the pad surface ensuring they are always clean, provide more biting edges for the pad which enhances grip, and more evenly distribute heat across the face of the pad compared to straight slots. These rotors also utilize a CM-250 alloy specially formulated alloy by a reputable brake manufacturing company. This iron alloy according to 034 is supposed to be extremely resilient to track abuse, so this is a good thing to have on rotor designed for heavy track use. And last but not least, these rotors have slotted mounting holes to enable them to fully float when used with the 034Motorsport hats and their bobbin system.



The rotors are also coated with a thin layer of anti-corrosion silver material (that appears to be metal) that allows these rotors to be stored without corrosion concerns. This coating will immediately scrap off of the area where the brake pads will sweep upon first brake application, but remain everywhere else to ensure these areas do not corrode (so the rotor ring where the hat attaches, the vanes, etc will still be coated and protected from corrosion).

If you’d like to read more about the technology in these rotors, here is my full review: https://f87.bimmerpost.com/forums/sh....php?t=2049119



Bobbin System and Supporting Hardware:


Credit: F87Source



Credit: F87Source



Credit: F87Source



Now we will examine the Bobbin system and its supporting hardware, each replacement rotor will come with new bobbins and new rotors and this is what enables the floating of these rotors.

Note: the bobbins and its supporting hardware are all made of stainless steel or corrosion resistant material, this ensures that the hardware will never fail due to corrosion and is resistant to all sorts of road conditions.




Credit: F87Source


A bag of hardware, like displayed in the image above, will be included with each replacement rotor. The hardware inside consists of the bobbins, bolts, washers, spring clips, and spacers which we will now examine.



Bobbins:


Credit: F87Source



Credit: F87Source



Credit: F87Source


The 3 images above show the stainless steel bobbin. These bobbins have a cylindrical tube section that slots into the rotor friction ring and allows the rotor to float both axially (expands up and down the shaft of the bobbin) and radially (rides the slot on the rotor outwards and away from the hat, or inwards and closer to the hat) with respect to the rotor hat. The bobbin also has an internal female thread that allows the cap head bolts to thread into them and secure the rotor ring to the hat. Finally the end of the bobbin is a semi-circle that allows it to grip the hat and prevents the bobbin from spinning and loosening the bolt.



Anti-Rattle Clips:


Credit: F87Source



Credit: F87Source


These 2 images above shows the anti-rattle clips that are part of the bobbin system. These anti-rattle clips deform like a spring when you tighten down the bolt and bobbins and exerts a bit of force (not too much, just enough to stop the rattle but not enough to resist the expansion of the rotors due to heat) to pinch the rotor to the hat and prevent them from moving and rattling around (because floating rotors have play in them to allow for the rotor to freely float and thus freely expand). But when the rotor wants to expand, this anti-rattle clip will be free to flex and bend and give way for the rotor to expand axially. The exerted force also provides a bit of friction between the rotor and the hat which also prevents rattling due to the free floating nature in the radial direction.



Washers and bolts:


Credit: F87Source



Credit: F87Source



Credit: F87Source



Credit: F87Source



The first 2 images above show the stainless steel round washer and what appears to be a zinc plated square washer. These washers are used in the bobbin system to disperse the force from the bolt head to the anti-rattle clip and from the underside of the anti-rattle clip to the rotor.

The last 3 images shows the A2-70 stainless steel cap head bolts, meaning they are austenitic acid proof stainless steel capable of at minimum 70 kg of tensile strength per bolt. Since the friction rings are held to the hat by 10 bolts, the fastening mechanism should have least 700 kg of tensile strength - which should be more than the rotor ever sees as the fastening mechanism on rotors mainly see shear forces not tensile forces, and the larger and stronger bobbin handles these shear forces not the bolt). So the use of stainless steel and corrosion resistant materials should allow the bobbin and the related hardware to always remain corrosion free regardless of road conditions.


Bobbin System:


Credit: F87Source



Credit: F87Source


These final 2 images show the fully assembled bobbin system. Note: You will require blue loctite to secure the stainless steel cap head bolt to the bobbin when assembling it, you should also clean the bolt and bobbin with brake cleaner (and any other cleaners - pretty much follow what loctite recommends or whatever thread locking product you’re using recommends) to ensure the surface is clean and ready for the loctite to cure.




Radial Floating in Action:

Finally I would like to demonstrate the radial floating.



Credit: F87Source



Credit: F87Source

From the 2 images above you’ll notice that the friction ring’s holes in which the bobbin slots into are not perfectly round, they are elongated. This is what allows the bobbin to ride towards and away from the center of the hat allowing the friction ring to expand radially. When the friction rings get hot they expand outwards so the bobbin rides in the slot and gets closer to the hat (technically the bobbin is stationary, and the friction ring is the one moving and expanding and as it goes outwards the bobbin moves to the end of the slot (to the side closer to the hat) on the friction ring). As the rotors cool the bobbin will ride to the opposite end of the slot - the side furthest from the hat.



Credit: F87Source

As you can see from the image above, when the bobbin is installed there is plenty of room left over in the hole for movement of the bobbin, and this is the position the bobbin would be in when the rotor is cold.



Credit: F87Source

This is the position the bobbin will be in when the rotor has expanded radially when it is hot.



Now here is a video showing the play (amount of float) the bobbin will have in the friction ring slot.


Credit: F87Source


Notice the amount of play is quite significant, allowing the rotor rings to expand however much it needs to when they get hot. This normally would cause a lot of clunking noise as shown in the video below (this floating rotor in the video below doesn’t have anti-rattle clips):

But the anti-rattle clips prevent this rattling (you can shake the 034Motorsport rotor when they are fully assembled and it will not rattle, it will feel like a solid 1 piece rotor when you do so, because the anti-rattle clips are extremely effective in doing their job) and allows you to have the benefits of a fully floating rotor without having to deal with the rattles.



I couldn’t show the axial float because I didn’t have a hat on hand, but you can imagine axial float occurs when the friction expands axially (gets “fatter”) due to the heat expanding the metal. The friction ring would then compress the anti-rattle clips and move along the shaft of the bobbin.

But in conclusion this bobbin system allows the 034Motorsport rotors to float both axially and radially which prevents them from warping under extreme heat due to track use.



Installation:

Now I would like to show the installation instructions so you will have an idea of how to install these new friction rings. The overall process isn’t hard at all, but you will require some basic tools like a torque wrench, blue loctite, and metric hex bits. Other than that this process is very straightforward.


Credit: F87Source



Credit: F87Source



Summary:

To wrap up this review I want to talk about my experience so far with the 034Motorsport rotors and I must say I really love them, they are performing absolutely perfectly on my car and have been flawless thus far. The rotors have been quiet (there is a slight metallic rubbing noise with the windows down, but you really have to strain to hear it and the surroundings must be quiet for you to be able to pick up these sounds), they have not rattled, and there are no issues with corrosion or excessive wear at all. The bobbin system has also not caused me any issues whatsoever.

Furthermore if you look at other users who have put on more mileage than me, for instance this user:


Credit: jfritz27 https://f80.bimmerpost.com/forums/sh...94&postcount=3



Who has put 12 heavy track days on his 034Motorsport rotors and a bunch of street miles on it as well (he uses his car as a daily), you can see the rotors look absolutely fine for such heavy abuse. It pretty much just shows the faint micro cracks starting to appear which is standard for any iron rotor that sees extensive track use, but the cracks are still very faint and very small and far from the edges, and his rotors are approximately 29.6mm thick so there should be plenty of life left. This should be a testament to the quality of these rotors, even when beaten on track.


So in summary these rotors are an incredibly good deal for the F8X BMW M2, M3, and M4 platform (especially with the lifetime warranty if you purchase from select vendors like FCP Euro) and with the potential to replace the friction rings and supporting hardware for such a low price - I truly think these are the best 2-piece floating rotors you can get for this platform. If you track your F8X vehicles and are looking for upgraded brakes, I can’t think of a better choice than these 034 Motorsport rotors.

[F87source]

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