Cobalt SS brake pads radial depth is 52,1 mm. JCW 4-pot Brembo radial depth is 55,6 mm. 3,5 mm difference. Cobalt pads can not use the whole surface of MINI discs.

 

Sorry, but this fact means nothing.

 

You need radial mount calipers. No lug mount calipers will fit easily.

 

Yes about 1/8" difference in height but the Cobalt pad is longer by about the same 1/8" (4 mm)

 

The length is not that important as the height is this case.
If we take two pads with the same pad area, but with different radial depth, then the pad with bigger radial depth will run colder since it will rub bigger disc surface. The bigger the working dics surface is the colder it is, the colder the disc surface is the colder the pad is.

 

That's why it's not a good idea to use wilwood calipers with OEM 294x22 mm MINI discs instead of OEM MINI calipers. Cooper S R56 pads have much bigger radial depth than Wilwood pads.

 

All good points but for what I plan on doing with my car and considering the cost of Gen2 JCW calipers, this appears to be a viable option.

Any good roads over in Belarus?

 

I can't say that they are good but they are acceptable in general. Our western neighbors have better roads, but eastern neighbors have much worse roads.

 

As I use 16" wheels for racing and for winter I have made my own BBK for track and DD.
I use Porsche Cayman S/Boxster S/911 996 front calipers. They have exactly the same piston area as R56S/JCW stock calipers. So they have stock pedal travel and do not influence brake bias themselves. They have asymmetrical piston sizes for even pads' wear. 36/40 instead of 38/38 of JCW Brembo. The pads are thick and have big radial depth - 62 mm. JCW 4-pot pads have 55,6 mm, GP2 - 61 mm, AP Racing MINI 304x24 kit - 46 mm, AP Racing CP5200 and MINI Challenge calipers - 50 mm, Wilwood MINI 4-pot - 42,5 mm. The bigger radial depth is - the bigger actual friction surface of the disc is. The bigger actual friction surface is - the lower peak temperature of surface is.
I use 310x28 brake discs of Alfa Romeo 166. They have 63,25mm annulus and ideally fit the pads. I use Fremax discs. They have a bit wider air gap than Brembo (12,5 mm vs 12 mm) and lighter weight (8 kg vs 8,6 kg). JCW 316x22 discs have air gap 7 mm, GP2 330x26 discs have 9 mm. Also they are claimed to be high carbon. I don’t state that they are better than Brembo, but that is my choice. As all Alfa discs they are cheap.
To install Alfa discs I used spacers (stainless steel shims) between the hubs and the discs. The shims provide the required disc's position and protect the hubs from overheating.
Also these calipers can be used with 305x28 mm Alfa Romeo Giulia discs, if 310 are too big for certain 16" wheels. Probably some 16" could accommodate these calipers on 315x28 BMW M3 discs, my 16" require too big spacers.
Using the shims the position of the caliper can be adjusted in wide variety in axial and radial directions to install different discs. There is a bunch of variants. The maximum size of the brake disc which can be used with the stock 17" wheels is 330x28 (Alfa Romeo Giulia). GP2 330x26 discs fit fine and bolt-on. The most attractive but costly discs are 325x28 BMW M3 E46 discs. Custom 2-piece discs is another talk.

 

I’ve been thinking about your idea to slot the holes that you are going to mount the caliper to and I think that might have a problem with the lower bracket mount wanting to rotate inward. Maybe the bolt friction will hold it in place, but relying on friction to hold something in place isn’t the best idea. Did that post you found that talked about do this to mount a set of calipers also talk about this possibility?

 

Any chance of you taking some vids and posting them? Had a guy from Australia do that a couple of weeks ago. Also you an engineer as you have some great info? Your last post is GREAT!!!!!!!!!!!!!!!!

This thread was not started to discuss what the "best" brakes are but rather "options" that do not carry as much cost as some other choices out there. This particular option has larger pads and rotors along with the same size piston configuration as the Gen2 JCW caliper. One would think this is an upgrade for the Gen1 brake options and the non Gen2 JCW models. On whether a special bracket is required, I will know the answer by this weekend.

 

Wow, nice work assembling that.

A few questions though:
- The rotors look to have extra wheel stud holes in them. Did they need to be redrilled to fit the MINI?
- How thick are the rotors from pad face to pad face?
- do you have ducted air coming in through that hole in the dust shield?
- what track do you race on?
- How hard would it be to change the lettering on the caliper to say “MINI”? Ok, just kidding on that one.

Sorry “Whine”, didn’t mean to sidetrack your thread, but this is really neat info.

 

I do not plan on enlarging the entire existing bolt hole but rather only in a vertical axis direction. From my past career, I am of the thought process that today's engineers considerably over design as their professional brethren that walked over the sandbar have forced the matter. On the rotation matter, it would appear the bolt's torsional qualities would be involved and my feeble mind says a stronger grade bolt could address the matter. I can also envision the possibility of a bracket that the existing hub bolts pass through but also extends outward so that a deadman could be fashioned to assist in the resistance for the lower hub connection.

 

Some european cars have the caliper that are relatives of Cobalt calipers, I mean they use the pads of the same size. And these calipers are radial mount. There downside is that they have slightly excessive piston sizes 40/40 mm. The pistons have assymetrical placement.
These calipers are:
Renault Clio Sport 3/ Megane Sport 2 (312x28 mm disc)
FIAT 500 Abarth (305x28 mm disc)
Opel Corsa OPC

 

I am thinking that Brembo went with the different pad for the Cobalt as the hub on the SS went up to a 5 bolt from the 4 bolt. It would also be interesting to discover if BMW/MINI had any input on the outward shape of the caliper ("we do not want our product to resemble anything that GM offers") and I am still leaning toward a previous post where I noted an opinion that similar frames were used. In today's world where cars share platforms, would think brakes are no different. If I can ever find some Brembo technical info I will not be surprised at all to find out that all the internals are the same on the two and that the end with the transfer tube was made so that the same tube configuration could be used.,

 

-Yes. They have to be redrilled and the central bore has to be redrilled too. If the center bore on a certain disc is bigger we have to use centering rings or centering spacers like those for BMW M3 discs in this thread - https://www.northamericanmotoring.co...ake-discs.html
-I use 310x28 mm discs. These calipers are used with 318x28 discs on Porsche.
-No duct. Just the window. I keep dust shield just to protect ABS sensors and ball joints from heat. Probably I will remove dust shields in the future.
-Mostly I race on our local go-cart tracks in Belarus, but also some very brake-demanding tracks in Russia, and some tracks in Latvia, Lithuania and Ukraine. I also race AX on parkings.

 

As there are some real good minds here, what would the main detraction be for mounting the Cobalt caliper by not changing the lower connection point but only elongate the upper connection point by the 3/16"? I need to figure out how much material would remain if I did this.

As the rotation force is downwards, and as the elongation would impact a very small amount of horizontal axis material the impact on the hub may be minimal.

 

Do you have the rotors you want to use?

I would start by bolting every thing up just as it is and see where things land. The biggest issue will be the clearance between the outside radius of the rotor and the underside of the caliper. This needs to be a 1/16” or greater to account for the radial growth of the rotor as it heats up. Next will be where the pads wind up on the rotor. If both of those are acceptable, then you are done. Even if the pad is a bit inboard of the outer edge of the rotor, it won’t make a noticeable difference. If you need to make a change. Make measurements in place; you might not have to change things as much as you originally thought.

No basis for saying this, but, I would change both of the holes the same amount and not change the rotor rotation lines across the rotor.

 

You could easily fabricate a washer with a tab that goes into the hole in the hub bracket and ensures the bolt stays in the right place.

 

There are steel bushings with 2mm wall thickness there. Not just holes in iron.

 

The washer is a great idea, should be able to fab out of some fender washers. Would hem the tab over to make it thicker and then use one both top and bottom.

Not going to buy the rotors until I am sure the caliper can be mounted but after seeing what cooper_a pulled off what I have planned should not be that difficult.

I hope . . . . . .

 

Put one of your stock rotors on and measure from it’s OD (of course accounting for the dia difference). You can put the pads in and see where they are relative to the hub. You should be able to see what you are actually dealing with before making changes.

 

I am going to make up a jig that I will tape to the top of the Gen1 JCW rotor that will simulate the Gen2 rotor. Based upon the only drawing I could find of the Cobalt caliper, hand made, stub for the hub attachment was about 1/2" that is close to what a Wilwood would be. There will be shim washers involved.

Of course I am getting ahead of myself but I am thinking about whether to paint the unit red or leave it black with the white Brembo letters. I have black rims so the white letters should provide a nice contrast. Also already chucking thinking about when some MINI person that does not frequent these forums starts scratching their head trying to figure out what brakes I have.

 

 

Does anybody know whether there is a Brembo part number on the JCW caliper? With the Brembo number would think we could pull up the Brembo technical drawing so that we could then compare other Brembo calipers from different make cars.