Front Brembo BBK - What to do with the Rears?
 

Hi Guys,


I'm planning to fit a Brembo 4 pot BBK to the front of my RX8. It is the version with the 328mm floating drilled rotors.


My rears are currently standard. What do people recommend to do in order to keep the brake bias the same as stock?


My thinking is to keep the rear calipers standard but get the rotors upgraded. Is there a company out there that does floating drilled rear discs for the RX8 at all in standard rear disc size? I've searched Google but couldn't find any at all. Most are drilled and grooved which don't really match the front brembo rotors... Or do I just leave them completely standard and just upgrade the pads?


Would appreciate people's opinions on this. Thanks for all replies.

I have standard calipers in the rear with two piece Racing Brake rotors in the rear and RB pads. But really the stock braking system is more than sufficient so BBK's are really for bling points. I only installed my Racing Brake BBK because I bought it off a buddy cheap.

I would like to do the same but the Racing Brake Rotors are slotted are they not? It would look odd compared to the front drilled discs...


Same story for me, guy was selling parts off his car and it was cheap so I couldn't miss it. My preference would also be slotted rotors.


I don't think anyone does a 2-piece drilled rear rotor so like you say I might just have to leave the rears stock. My only concern is that once I have the 4 pot on the front the brake bias will be more front orientated.


I suppose what I could do further down the line, is swap the front drilled rotors for the RacingBrake 2-piece slotted ones and then get the matching rears I guess...

If they designed the kit properly, it'll keep the balance the same as stock. Also, I think DBA makes 2 piece rear rotors, but I don't know if they offer them in drilled. My vote is to keep it stock.

Well it is a Brembo so I would hope so! Think i'll be keeping the rears stock in that case, but making sure both the front and rear pads are the same compound.

nothing. if you need to slow from 100mph to 40mph repeatedly in a short period of time, get vented rotors.

The stock rears ARE vented. If one really wants or needs bigger rears, Mazdatrix does sell a 13" rotor kit that relocates the stock caliper, so you get to keep the parking brake, but it will influence the brake bias somewhat.

Just to add, drilled, slotted, 2 piece or 1 piece won't have any real effect on the brake bias, so no reason to upgrade the rear rotors on that basis.

Going to a bigger rotor, different piston size, or different pad size (or pad compound), will affect it. As mentioned above, I would expect a front BBK to be designed to work with the stock sized rear brakes.

Pad size shouldn't cause the bias to change unless it's changing the effective lever arm that the pad is acting on the disk, usually approximated as the halfway point radially. So if one had a pad that's very thin radially at the outer edge of the disk, it'd increase the lever arm, but that's about the only way pad size should cause a change.

I'd also add that drilled, slotted or any other "fancy" rotor isn't an upgrade. If you like the looks and want them for that reason, then great. Don't expect any other advantage, but DO expect that they'll likely crack sooner than a plain disk when used really hard, like on track.