Drop an anchor! Miata rear brake bias...or lack of

I went with 1.8 brakes in the rear and was pretty happy with them.

Keith Tanner wrote: Yup, you could go to 1.8 brackets in the rear. You just need the matching pads and rotors. Note that you have the possibility of also using the Sport calipers on 1.6 or 1.8 brackets. That gets you a slightly bigger rear piston (1.25 vs 1.375", if memory serves) which will give you more rear bias.

I thought the Sport calipers were only compatible with their own brackets. Must've gotten mixed up.

Okay, so: 1.6 rotors/pads in front, 1.8 rotors/brackets in rear with Sport calipers and pads?

The front Sport calipers only work with the Sport brackets, the rears fit the earlier brackets.

The Sport rear calipers may not be necessary, but it will give you more rear bias. If you've got healthy calipers currently, I'd work with what you have now and only go to the Sport calipers if you need more rear brake torque. The pads are determined by the brackets you use, so changing calipers wouldn't require you to change anything else.

Keith Tanner wrote: The front Sport calipers only work with the Sport brackets, the rears fit the earlier brackets. The Sport rear calipers may not be necessary, but it will give you more rear bias. If you've got healthy calipers currently, I'd work with what you have now and only go to the Sport calipers if you need more rear brake torque. The pads are determined by the brackets you use, so changing calipers wouldn't require you to change anything else.

Thanks!

Although I want to clarify that last sentence - if I buy 1.6 pads, they will swap into a Sport caliper later on? Provided, of course, that the rotors/brackets don't change?

Not that pads are expensive, but the pad doesn't change? Just the piston diameter?

I read that the 1.8 front calipers are different than the 1.6, but the rear calipers don't change from 1.6 -> 1.8. There seem to be conflicting opinions on whether a 1.6 pad in a 1.8 front is a good idea, but do-able.

Never mind, got my answer from this thread

https://grassrootsmotorsports.com/forum/grm/better-brake-calipers-for-miata/101566/page1/

To keep it all in the same place: the pad shape is dictated by the bracket used.

1.6 and 1.8 front calipers are interchangeable although not 100% identical. You have to swap sides.

So 1.6 and 1.8 rear calipers are different? Are they also interchangeable?

Just so I can bookmark this thread and forever have a definitive Miata brake reference.

1.6 and 1.8 rear calipers are identical.

Want a definitive Miata brake reference? Pick up How To Build a High Performance Mazda Miata for $2.99 on Kindle before the end of November.

Thanks for the information guys, I have often felt that my '97 NA had a front brake bias.

Forgive my ignorance, there was a Sport model that had different front brakes than the regular 1.8 NA? I had only heard of the Sport in reference to NB.

The brakes usually called "Sport" were introduced in 2001 and became standard in the US in 2003. They can be retrofitted to earlier cars in full or in part.

From memory, I reserve the right to make mistakes.
1990-93 brakes were approximately 9" in diameter and had 2" front pistons and 1.25" rear. Master cylinder was 7/8" and it had what I'll call Booster A. These are usually called 1.6 brakes.

1994-00 brakes were approximately 10" in diameter with the same piston, master cylinder sizes and booster. The only significant differences were the rotor diameter, pad design and prop valve. Usually called 1.8 brakes.

The 2001 Sport model introduced the "Sport" brakes. 11" rotors, unique front calipers with a 2.125" (I think) piston and a rear caliper that was externally almost identical to the 1.6/1.8 units but had a 1.375" piston. There are some casting differences but nothing that concerns us. Master size went to 15/16" and two new boosters were introduced: Booster B with dual diaphragm and a big boost ratio, and Booster C that was a bit stronger than A. These boosters use a different pushrod design than the earlier 1990-00 ones.

Interchange:
- You can consider the caliper brackets, the pads and the rotors to be a matched set. This is true for both the front and the rear. If you want to use Rotor X, you will need pads and brackets off the same car. Note that parts stores will consider the brackets and the calipers to be part of the same assembly.
- 1.6 and 1.8 front calipers can be considered interchangeable, although you do have to swap them from side to side when mixing and matching. You cannot use them on the Sport brackets/rotors/pads.
- The Sport front calipers can only be used with the Sport brackets, you cannot use them with the older brackets/rotors/pads.
- All three rear calipers can be considered directly interchangeable.
- You can use any of the late (2001-05) masters on any of the late boosters. There's also a 1" master from a 929 that can be swapped in, and I suspect there's a 1" master from an earlier 929 that will fit the earlier booster - but I've never followed up on that to know for sure.

My street car runs a 15/16" master with Booster C and 10" rotors. My calipers are Wilwood Powerlites all the way around, but they're sized like the 1.8 fronts and Sport rears. There's an adjustable prop valve as well.

The Targa Miata runs a 1" master with Booster C and 11" rotors. Calipers are Wilwoods again (Dynapro 6A front and Powerlite rear) with the same piston sizing and an adjustable prop valve.

In reply to Keith Tanner:

Thanks Keith! And I would, but a little birdy told me I'm getting a hard copy for Xmas. Must have paid full price too (gotta get you those residuals).

Then again, my phone is always in my pocket when I'm working on the thing, and I have the kindle app...

I'm getting both hard and digital copies. Thanks for the heads up Keith.

Keith Tanner wrote: - You can use any of the NB (1999-05) masters on any of the NB boosters.

I think you mean NB2 here instead of NB because of the pushrod length?

I wasn't 100% sure last night if the change happened in 1999 or 2001 - I've seen some indications that it was earlier. The part numbers do confirm that it did happen in 2001, though. I'll correct the post.