Brake Upgrade question

[RS2000]

NB2 -> Front = ventilated, Rear = Solid

Same for all MX5's from NA to ND.

Maybe a lot of cars have the rear rotor larger in dia. than fronts, but I've never owned one in 40 years. As far as I know, the NB2 is the only factory MX5 like this, & I am interested to know why.

Cheers

As I said, it was to do with what they could fit inside the factory 16" rims (NB2 went to a 16" rim compared to the 15" rims found on the NB1, a lot of 15" rims don't fit over the NB2 brakes)

They could get away with a smaller disc rotor on the front (required because of the larger caliper) because it is thicker and ventilated.

Thanks Nevyn72, but you're missing the point I'm trying to make, so I rephrase another way:

The NB2 has 270mm dia. front rotors. So why didn't Mazda make the rear rotors 270 or less, as all other MX5's have the rear smaller than (or equal to in some cases) the front.
Also, ALL MX5's have thicker ventilated fronts & solid rears.

Cheers.

[kazama]

I often wondered the same. I just assumed it was if they ran a smaller rear rotor they would potentially have to look into moving away from a solid rotor in order for it to be a good match to the larger front. Rather than go to that effort they just upped the size so the solid rotor could still perform as required. Total guess though

[Nevyn72]

The NB2 has 270mm dia. front rotors. So why didn't Mazda make the rear rotors 270 or less, as all other MX5's have the rear smaller than (or equal to in some cases) the front.
Also, ALL MX5's have thicker ventilated fronts & solid rears.

Ultimately it's a question that only Mazda engineers can really answer accurately....

Perhaps it has something to do with the ABS?
The NB2 was the first to get this?
What are the relative brake sizes on the NC? (ND are 3mm smaller on the rear)

[RS2000]

I use W5 front and W3 in the rear and since the rebuilding of the rear calipers and NB8B proportioning valve my rear braking is a lot better, not perfect but getting there.

Hi Magpie, is that a NB8B or NB8A proportioning valve?
I've read a lot of old posts, & many say that NB8B's dont have proportioning valves, but use EBD & ABS instead. One post said the 'valve' on the 8B is just a thru' passage fitting.
Or did you obtain a PV from an overseas non ABS NB8B car?

Cheers

[Magpie]

It is a NON ABS proportioning valve from memory. I will ask the question when talking to Automotive Plus net.