Howdy y'all I have a Maserati Gransport, and one of the issues with the car is that the brake rotors are massively overpriced and very low quality. While I looking for new rotors I was told that the 456/550/575 all shared the same rotors which would mean that you potentially have the same issues with finding good quality or cost effective replacement rotors, so I thought I would share what I've done here in case it helps anyone in the future. My solution uses off the shelf rotors for the front and are more than suitable for racing, though the 2-piece set up I used is designed for street and track days. Image Unavailable, Please Login The rears use a modified rotor as the clearance for the handbrake was... snug... but I did eventually find a solution, and AFIK it is the only one. Image Unavailable, Please Login Image Unavailable, Please Login I'm currently in the process of having a few adjustments made to the parts before they get fitted and I start testing brake pads. Hawk Performance has been helping me and I'll be testing their PC road pads, HT10 and DTC-60 track pads. If I'm honest, the main reason I did this is so I could make some interesting content for my youtube channel, however as I know that finding quality rotors and pads is an issue for my car, and presumably your cars I thought I'd throw it out there in case anyone needs some help. I'll be putting up the whole engineering and design process as well as testing on my youtube channel over time. If unnecessarily technical detail about how rotors and pads work is your thing, then please keep an eye out. If you're curious about the whole engineering process, you can find it here https://www.************.com/threads/why-im-making-my-own-brakes.125090/ In the meantime, here are some cool pictures. Some rotor temp predictions for road and track use that I used for selecting pads: This is a cutaway CAD model I made of the OEM front rotor Image Unavailable, Please Login These are the final revisions of my front and rear setups. The bolts are Milspec, and they are actually coloured gold. https://www.************.com/cdn-cgi/image/format=auto,onerror=redirect,width=1920,height=1920,fit=scale-down/https://www.************.com/attachments/1596272375007-png.132780/ https://www.************.com/cdn-cgi/image/format=auto,onerror=redirect,width=1920,height=1920,fit=scale-down/https://www.************.com/attachments/1596272327218-png.132778/ I correctly modelled the vanes and bolts so I could complete correct structural and thermal analysis, and ensure that the bolt shanks took the load from the rotors. Image Unavailable, Please Login In the full thread all the dimensions are available, so you should be able to copy what I've done, or you can ask me for drawings. The rotors are commonly available around the world, so if you're into that level of DIY I'd be happy to guide you, but if you're not I'd be happy to help as well. As for costs, I paid $1564.56AUD (about $1100 USD or 850GBP). I got lucky with some promotions at a local retailer and got the rotors at 30% off. They would probably cost between $2k-$3500 for all four corners if you wanted to do the exact same thing again, but then you own the hats and only need to replace the rotors in the future. Hope this interests some of you! Well, the pictures of the completed rotors didn't work, and I can't figure out how to fix it - so I'll try again... Image Unavailable, Please Login Image Unavailable, Please Login
Very cool and impressive work! Years ago I designed similar for my E31 and E38 BMWs before switching to off the shelf stuff due to ease/speed. Options for 550/575 rotors include: Floating: - Brembo (they sell replacement front floating rotors only in our size; note this is DIFFERENT then the "big brake" or GT upgrade); Prices vary over the years but over $1k, under $2k historically - Girodisc (also sell floating replace disks with hats) - Site sponser; I have used their disks on various BMWs through the years $1100 (https://www.************/Rotors_c_504.html) - One other racing company in the US that I forgot the name of. (I think they were a Nascar supplier? maybe?) Someone will likely chime in. They cost under $1k / pair. - yourself Solid: - OEM - Formula Dynamics - http://formuladynamics.com/products/550_brake_rotor/550_brake_rotor.php Ultimately its a balance of weight vs durability vs cost. I also tend to think the 550/575's braking is a bit under whelming in stock form. (The later carbon brakes fixed that issue) For what its worth, if you go fully aftermarket..the door is wide open: - Brembo GT - MOVit - Stoptech - etc
Curious out of these options which are considered to be the best option? Or would it be based more on preference?
lol, I now want to refer to myself as yourself. My setup is 2-piece but not floating, which is more suitable for road use due to reduced noise. This setup is pretty good until you really start heat soaking the rotors, so you could race with these no problem but you may encounter issues once you start getting into endurance events. Putting cruise control on and driving to a track day with 15 minute sessions is more my operational envelope! I'd have dig through my emails, but I have a feeling that I contacted Girodisc early in the piece (obviously it is far easier to buy something that already exists) and I couldn't find any of the 2-piece of floating setups that could also do a matching rear set. I know it is a petty reason, but I really disliked the idea of mismatched rotors just on the cosmetic reasons alone. If I hadn't been able to accommodate the handbrake I wouldn't just sucked it up and bought some OEM rotors. The main reason I started this whole process was I really can't stand cross-drilled rotors. They're not safe, corrode faster and contrary to popular belief, they actually have a tendency to overheat and do not cool better (this is because the cross-drilling reduces the surface area of the rotor, and so the pads heat up the remaining area faster). I definitely contacted Stoptech, they have a front rotor kit ready to go, but it was a MOQ of 10 (I think it was 10) and was proper fully floating racing gear, so was just completely overkill in price. I also contacted SpartaEvo (awesome company) but the volumes were too low for them to take an interest. I tried to get Willwood involved, and I tried DBA, but no one was keen on making low volume rotors or setups. Designing my own set was so far at the bottom of the options, I more or less just ended up doing it out of annoyance! One thing I should probably highlight, is that I'm in Australia so the shipping costs from the UK (eurospares etc) and the US (FD) would've pushed the total costs to be equivalent to what it was to make my own. So I figured, for the money I might as well get something higher end and the only way to do that was DIY. This isn't my day job either, I spent so long talking to engineers with experience doing this and so so long looking for something off the shelf before I committed finally. So yeah, the tl;dr was that this was about the same price as OEM locally but much higher quality, looks cooler and was the only way I could match the front and rear rotors, clear the handbrake and 'delete' cross-drilling. And anodising looks cool! I'm not surprised the brakes are underwhelming in stock guise - they're barely suitable for the Gransports lat alone a heavier and faster car. There is no brake ducting either on the Gransport. The thermal mass is suitable, but it is definitely in the range of you need task specific pads. I'll be playing around on youtube with the pads Hawk send me. I'm fully expecting the road pads to cook on a track day, but I'll run them anyway just for the sake of making a video and getting out more info for the community. The DTC60s will last, they have epic thermal range and a very consistent mu curve. Hawk and AP are the best, they share all their engineering data at consumer levels. DBA and Willwood do the same with rotors. I spent so long going through catalogues to do all this, and it really helps when the information is actually provided without needing to sign an NDA and sing and dance... Image Unavailable, Please Login I do fangirl over the 575 a fair bit. I tried to convince my fiancee that we should invest in one as an asset during the viral apocalypse, but she remained unconvinced... Maybe next time...
IMO, its just preference. Cost v Cosmetic v Performance. Some people love the look of cross-drilled rotors, but they're prone to cracking which doesn't suit my use. But me making the rear set match was purely cosmetic since the rear rotors only do ~30% of the workload anyway and so the OEM set are good enough.
Exactly what he said. To give an answer, one would need to know what your relative priorities are. OP here appears to have made an quality product reflecting his particular needs, which one can argue is shared by many others (Particularly if you are down under!)
Also in aside, Stoptech used offer a rotor upgrade for NSXs that let you keep your oem calipers. I wonder if we could do similar for our cars. A 355mm square floating setup would be nice.
If you can find someone in Perth who is willing to let me pull wheels off of their car and take measurements or someone who wants to chat with me and take measurements as I direct, then I can do it. I was about 3/4 of the way down doing it that way for the Gransport so I could extend it without much effort. The reason I didn't though was that the 330mm rotor I selected had the same thermal mass as most 355mm rotors due to the large annulus. The calipers themselves are great, they don't need an upgrade so a dogbone to accommodate a larger rotor and yeah, between what I've already done and the fact I have some models of 355mm and 380mm rotors made I could probably do it in a few days.
Your right, the the beauty of a ~355 mm floating rotor is that it doesn’t weigh much more than a 330 mm, But you get the added benefit of increased brake force (further from the center), and a greater area to distribute cooling, while still fitting under most 18 inch wheels. Going much larger and you start really stressing/wearing out your bushings (I built/ran 380mm and 390mm custom setups...ask how I know), with added weight. Wish you were local, I would happily let you use mine. Unfortunately work/deadlines limit my free time.
You wouldn’t happen to have the factory piston diameters by chance would you? I’m curious what the brake bias actually calculates out to on these cars.
Only difference in brakes between the 550 and 575M is one size difference on the rear pistons. Different ABS, of course. 575M Brake Calipers Type Fixed, 4 pistons Brand BREMBO Piston diameters 38/46 mm (front) - 30/34 mm (rear)
My ‘back of a napkin‘ calculation comes out to 64% assuming a 330mm front rotor and a 310mm rear with matched pads. That’s honestly near perfect (and what we would shoot for in my German V12 coupes).
Great to see these rotors, nice work! I spoke with Girodisc and they don't make a rear disc because of parking brake clearance. After seeing your design I see why they had clearance issues. Link (or p/n) for the Brembo 2 piece rotors? All I can find is the GT kit.
https://www.brembo.com/en/car/sporting-use/discs It was part of their "TURISMO" line, but it doesn't look like their catalog is up currently. Edit: As you know, that is different than then "Gran Turismo" line. I can't find an older version online, but I did come across this nice info guide: http://mqauto.it/wp-content/uploads/2015/05/Brembo-GT-Technical-Information-20141.pdf Edit 2: Found a version but it looks like the 550/575 front disk has been dropped (they also seemed to have dropped their Aston Martin options...must have been poor sales?): https://www.brembo.com/en/Varie/BremboTurismo_ApplicationList.pdf Someone better then me at looking up older versions of websites maybe able to get an older version that listed it. It was also only front.
To my knowledge the 550 rotors from ferrari are available. The girodisc rotors and hat design are race proven reliable can be made to float and are available for the 550. I have them on my car right now. It is always easier (usually better) to adapt a caliper such as the AP from essex and custom make a support bracket if no off the shelf bracket exists, than design a new rotor and hat to fit the oem. The future is a database of these brackets and then brackets milled from billet aluminum and sent as part of a kit with the calipers. IMO i see no reason to ever use a 2 piece hat disc unless you are floating. However there are times it makes sense. On the big brembo mustang GT the rotor is 35lbs. in the Aftermarket the AP, and PFC floating rotors are 25lbs. So that's 40lbs of rotating mass reduction from 1 component. That's worth it!
I just had a look through my notes, there were a couple of rotors I short listed that were 355mm. They're all a pillar design (typically lighter and stronger than vaned, so they allow for a larger air gap and thinner walls). They're DBA rotors, and can be bought plain, cross drilled, or slotted (like the photos I put up). The only detail I need is for mounting the caliper and dog bone and I could do this. I have the front caliper as 20.5436.00 1A on my Maserati, and google tells me for the it is 20.5438 for the 550/575, but visually the calipers look exactly the same and I'm betting that they are. I just don't want to assume they are and get it wrong and not have them fit. If someone can give me the centrebore distance (red line), and the mounting lug thickness (blue line) I can design this for you. If this is something you want I'd be happy to help. Only thing I would say is that unless you're conscientious about how your car is run/setup, don't get Aluminium rear hats like I did. If you let the handbrake drag, or leave it up the heat will warp them. I can get them made out of Steel and resolve the issue, but its a bit more expensive! If you can find someone in Perth, Western Australia I can measure it up, I have spare time! Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
calipers can be the same but different pistons. Piston size is bore + volume displaced. The system is matched to all work together. Just because it fits does not mean it will play well with each other. Lots of testing goes into brake systems by OEM's. Stoptech developed the SCCA T1 racing brake kit on my corvette racecar. They don't do anywhere near what the OEM's do but it was still an involved process of empirical design, part selection, and on track testing by knowledgeable people. With more time and money additional development could have been done too.
Big problem, as noted, is the rear rotors with the brake drums. Took forever (several years) to get my custom ones from Mov'It. They do not even offer them now.
100% agree. What I did was really just about replacing the rotors with OEM equivalent and even that was a mission. It is annoying, my MX-5 has integrated hand brakes in the caliper... since 1989...
Those generally do not work as well as the separate brake shoes in their own drum. Not as big a pain to adjust, though.
This was nagging me: the other Racing commany who can reportedly make rotors for <1k was Coleman Racing
I've been driving around with these for a while now, super please with the results! Thanks for the support guys! There will be a follow up video eventually showing their performance!
