I have a 2013 non-S which came with 15" alloy wheels. I do plan on upgrading to 16's for non-winter use starting next spring but will keep the 15's for winter driving. I think narrower tires will handle better in the snow.

I happened to stumble upon a complete set of Cooper S front brakes (calipers, rotors and pads) for sale, taken off a brand new car with 10 miles on them and was tempted by the price ($350).

Then I thought about how if I go to the bigger front brakes, I'll no longer be able to use 15" rims in the winter since they wont fit.

Im not sure the benefit of bigger brakes outweighs that of being able to use my 15's for winter use.

SO, my question is....how much better would my braking possibly be with the bigger calipers? Is it worth the bother and opportunity cost? I have noticed my stock brakes work really really well. We have lots of red light cameras in NJ and I often find myself stopping on a dime to avoid running red lights.

And in case anyone is tempted to say "use the search" I did search first and couldnt find anything about this, hence the thread.

 

Bigger brakes do not mean you can stop better. How fast you can stop all depends on the grip of your tires. It also depends on how much brake torque your calipers are producing. Too much braking power (i.e calipers too big for the car) and you will easily lock up, resulting in longer braking distances. Larger rotors only increase heat capacity (efficiency). If you don't track/autoX your car, there is no need to get bigger brakes. Unless you want it for looks.

Going from non-s brakes to "S" brakes is not worth it. You will most likely not notice a difference in braking. If you want to improve braking feel, just get yourself a set of Hawk or EBC pads and powerslot rotors (or whichever rotors suit you best). You will be able to modulate your braking much better and have less brake dust.

 

Thanks for the detailed response. The normal "S" brakes arent anything special to look at, and I agree that my "Justa's" braking performance has been more than adequate. So, I'll just resist the temptation to jump on this deal.

 

For the record, I've since discovered the calipers for the "S" and the "Justa" are the same part number. The only differences are the caliper carriers and larger brake rotors. So, I guess the advantage to these brakes are fade resistance from greater surface area. I'll justa stick with my stock sized setup. LoL

 

My brakes have issues under racing at constant hard braking around 40mph to near dead stop, I do that 3 times in under a minute... And good buy stopping power...

 

I didnt know they could fade so quickly under hard braking.

 

Stainless steel brake lines will get rid of fade.

 

Fading that fast is USUSLLY the result of older brake fluid....(it boils when water logged)...or pads overheating.....
Mini's use dot4 fluid...has a higher dry boil temp than older dot3, but is more affected by water...net result is it should be flushed every 36 months in normal driving and before EVERY track event.

 

Yeah and we also have one of the hardest cars to bleed lol. It's tricky with the abs system.

 

Actually nothing special about bleeding them if you don't let the resivior go dry.....
The old 2 person top down method is fine if you keep the resivior full....
Let it go dry and pump a slug of air into the system...and you have a headache on most any modern car....

 

That's right, if you do it right it's no different. Good pads and stainless steel brake lines is what I have for my daily driver I lap once in a while...

 

A pressure bleeder also works. You can put a bunch of brake fluid in it at one time and not have to worry about getting air in the line.

I will also suggest that the stock caliper are an issue with brake performance degrading. These are a big chunk of steel that absorbs heat and doesn't give it up quickly. Even with really good, high temp brake fluid and race pad these calipers seem to "heat soak" and the pedal will become soft. This is the best I can come up with from my experience with this issue.

 

What is the front rotor diameter on the R56 Justa?

Is it 294mm as well?

 

It's not the same sized rotor as on the "S."

That's why the caliper carrier is larger on "S" models....to accommodate the larger rotor even though the caliper is the same.

 

good info here. i'd stick with the stock brakes until you feel like you've maxed them out - i.e., as mentioned stainless steel lines, brake fluid (try dot4), and better brake pads should probably be considered first.

i'm constantly impressed by the braking power of the mini during autox - and that's with everything completely stock. i wish i could do stainless steel lines, will be switching to dot4, and staying on the stock pads frankly. This does not hold for track driving.

 

The stock non-s rotor is 280 mm. The S rotors are 294 mm. I am presently swapping to those larger rotors along with Redstuff pads and braided hoses. I ordered rotors and was shipped the larger S ones, do I figured I would upgrade to them. The caliper bracket should be here today. That is all I'm waiting for.

 

I have an SD Roadster in Yurp, which is a 2 litre 225 lb-ft diesel but pretty high-geared - it kinda pulls and pulls and pulls, so it's a bad joke that it comes with Cooper 280mm discs and not Cooper S 294mm discs.

On my previous justa Cooper I found the brakes uninspiring but on the SD they are borderline dangerous for really fast driving - and bear in mind my fast driving on country roads is often accelerate to 90, brake to 40, accelerate to 90, repeated several times a mile.

Converting my newish car to S discs was very easy - it's no harder than fitting new discs and pads and the hydraulics don't need to be touched, so an hour per side is very leisurely.

I would say the brakes are now adequate, rather than good, but that's still a step or two up from borderline dangerous. The next step when the current OEM pads wear out is to go to aftermarket fast road pads to see if they can get the brakes above adequate.

I did a photo guide to the changeover - attached below.

 

Thanks for that Angib!

 

I should perhaps give my experience of this change. I did it to cure the bad brake fade I was getting with Justa brakes - and that has been achieved.

My limited experience of American driving is that it would be hard to find an American road, except for maybe a few mountain descents (or racetracks), that required the sort of repeated big stops that was causing me trouble.

However I would not say the brakes feel any better after the conversion, just that they don't fade - hence the reason to try uprated S pads when the OEM S pads wear out.