Rear brakes - balancing large fronts
 

Starting a new thread here so we don't jam up Sav's thread with this stuff.

So I've been on the hunt for Sport rears (among other Sport brake components) for my 1.6 car. I see recommendations for the M-Tuned bracket kit (to allow use of the Sport rotors with 1.8 calipers), but I want to find the bracket for Sport rotors for two reasons:

1 - I want the Sport's larger piston
2 - 1.6l car, I'd have to source calipers anyway (might as well get what I'm after, right?)

I'm assuming I can simply get the calipers from most auto parts stores, same with the Sport BMC and possibly booster. So I suppose it's finding the bracket which is holding me up. I've emailed sites like Planet Miata and my emails have gone unanswered.

Any leads?

My local Napa carried them (caliper with carrier)

There are no brackets??

the sport brake caliper is offset to fit a ~10.75" brake rotor.

I found this out the hard way (which ultimately saved Braineack's ass)....

1. car came as a base model with teenie 01 rear brakes
2. I upgraded to the mystery Panache v8 big brake kit that used rx7 rear calipers.
3. I sold my stock brakes, calipers and all
4. I re-upgraded to the good-win version 3 kit which got me better rotors and hats and switched back to the stock rear brakes (sport or regular + brackets)
5. I bought calipers somewhere.. realized I didn't need caliper brackets with them and returned the brackets.
6. I bought brake pads "for my car" and they didn't fit but I held onto them for some reason.
7. today, several years later, brainy came over to figure out his crazy rear brake wear and noise problem. turns out his pad backplate got stuck in the caliper and the piston bent the pad and backplate all crazy. he needed stock non-sport pads. I had both sport and non sport. (sport are quite a bit more surface area fwiw).
8. he has brakes and didn't have to drive a no-brakes car somewhere to get pads.

so... yeah the sport rear caliper is offset the same as the spacer bracket already.

http://forum.miata.net/vb/showthread.php?p=4508004
look at post 74:
http://forum.miata.net/vb/showpost.p...7&postcount=74

you can kind of see how the sport brakes mounting holes are further from the center of the piston. the slider brackets also fit the larger pads.

if you buy the sport/msm calipers, you should get the whole assembly.

sadly though, raybestos and beck arnley dont list them.
autozone carries the duralast ones but they're $76 plus a 60 dollar core.

dgmorr, what was NAPA's price?

Most vendors I've found know these are sought after & rape you.
Best I've seen is $470 + S/H for a new pair.

http://www.r1concepts.com/mazda-miat...liperwheel.htm

http://www.r1concepts.com/PartImage/14145518.jpg

Koto, I think you can use your 1.6 calipers with the sport rotors and m-tuned's bracket. Same way we can use our 1.6 calipers with 1.8 brackets to use the larger 1.8 rotors.

Why the lust for the larger piston?

Huh... thanks a lot for that, I do see how the mounting holes are offset, interesting. So then what I'd need are the standard 94-97/1.8 brackets for the rear? Or am I assuming, once more, that there's a bracket exchange involved (mine's a '93)?

So then if there is no "Sport" bracket, my shopping list would be:

Sport calipers/pads
Sport rotors
1.8 brackets
Sport lines? (Different from 1.6 somehow? Am I assuming again?)
Wilwood adj. prop. valve
Optional: Sport BMC/booster/underhood lines

Based on advice from Andrew: "The sport calipers are a bit bigger and will give more rear bias to start."

He's never steered me wrong. He mentioned using stock calipers as well, but agrees that the Sport caliper is a more ideal solution.

calipers come with the brackets... these are the things that you clip the pads into and have sliders and mounting holes. they bolt to the rear hub holes.

I'm not sure about lines.

I don't think you need to do anything under the hood. (except prop valve if you want)

so your list might just be

sport calipers
sport rotors
sport pads

and then check the lines.

I'm sure someone on miata.net has laid it all out.

FWIW sport rear brackets brandie new cost 65 bucks apiece from MazdaSpeed.

Compared to 1.8 "normal" rears, Sport Rears add about 30% more rear braking action.

About 1/3 of that change comes from the increased leverage from the greater radius of the larger rotors.

About 2/3rds comes from the larger piston squeezing harder, like Hustler's Mom.

Awesome, I should have started this thread some time ago, thanks. Good info all around.

y8s - Yeah I don't need to do anything under the hood (except the prop valve) but there're a lot of posters in the dotnet thread you linked who go to bigger BMCs. I might see how I like the stock BMC with the TSE fronts and Sport rears.. but I'm anticipating a lot of pedal travel from the swap.

Koto, the single caliper I bought was $150 CDN. I have a used passenger rear sport caliper with a stuck bleed screw. There was an $80 CDN core charge in lieu of returning my used one. If you put $80 in my hands it is yours.

I just upgraded to the rear M-tuned upgrade. So stock 1.8L calipers with the 10.9" rear sport rotors. I already had the 11" front rotor upgrade and this significantly improved the balance, I'm a happy camper now.

I went from base 01 brakes to wilwoods + sport rears and my pedal travel is jim dandy.

Hmm, cool. I'll give it a shot.

Got a possible lead on some Sport rears from a PM. :)

So do we know for sure if 1.6 rear calipers will work with 1.8 brackets, mtuned's bracket, and the 10.9" rotor?

that's what I'm using.

Ah, good. You can understand why I thought you had changed calipers:

whoops. Well they are the same thing. I meant to say brackets.

But yeah, 1.6L car: 1.8L caliper brackets, 1.6L calipers, M-tuned Bracket, 10.9" Sport rotors.

I got a 4-wheel MSM setup from Tom @ PartsGroup. The MSM rear calipers are larger than standard 1.8 calipers. It was a significant improvement over standard 1.8 brakes. The F/R balance is substantially better than the stock 99 setup, and I have no pedal problems with the standard NB master.

I have read that the MSM/sport lines are somehow different than standard lines, but when I did the swap I couldn't see what the difference was. I went ahead and used the new lines because they were new, but I could have used the original lines if I had to.

Looks like 1" 929 master cylinder with the Sport Non Abs low boost assist vacuum booster and Sport calipers would balance out the front BBK the best after some reading. Maybe add a MC brace if you want stiffer brake pedal feel?

Found some info regarding 929 MC installation:

http://robrobinette.com/mastercylinder929.htm

Maybe I'm missing something, but wouldn't a proportioning valve be a simpler way tune the bias?

its can only do so much if you upgrade the front too much.

Miatas, esp the early ones, use FWD sized rear brakes. You know how wrong wheel drive econoboxes are so nose-heavy? Well the back of such cars have next to no weight on them. Hence they use weak rear brake calipers when they use disc brakes all around. The inexpensive Miata inherited such calipers from the parts bin… SO…an adjustable prop valve can be set to full rear (no line pressure reduction) and still not eliminate excess front lock tendencies on many Miatas.

If race series rules and your wallet allow, it's best to set bias via hardware changes to get things close, with a tendency to rear lock first. And then fine tune with a prop valve. That way you can use pads with desirable behavior front and rear. And the bias is much more ideal during light AND heavy braking.

If you get bias decent during all out stops without using a prop valve, then it will be way too front biased the rest of the time. As in the fronts doing most of the work even when not braking very hard. This leads to excess wear and heat along with trail braking woes.

Ahh, thanks for the long explanation. Sadly none of this is very applicable to me ATM, but its still good to know.

Not sure how much it matters, but it looks like that info is for an RX7.

oops..my bad

Hate to bring back an old topic, but has anyone done a comparison between the sport calipers with sport rotors vs the m-tuned/stock 1.8 caliper with sport rotor?

Is it really htis cheap to get sport calipers with the mounting bracket this cheap?

https://www.napaonline.com/Catalog/C...+50042+2042021

https://www.napaonline.com/Catalog/C...+50042+2042021

Hell, that's cheaper than buying the mtuned brackets to retrofit my current 1.8 calipers.

Am I missing something???