circuitmstr74

iTrader: (1)

I have searched and searched. I wanted to get some made several months ago and got sidetracked. Now I would like to revisit this if anyone has a lead or ideas?
looking for stock 1.8(non sport) 2 piece rotors. at least for the rear

wannafbody

iTrader: (1)

Purpose? Less weight?

circuitmstr74

iTrader: (1)

precisely

Leafy

iTrader: (1)

They'll have to be custom. The smallest 2 piece rotor that I can get off the shelf is 10.75. Trackspeed was supposed to be coming out with a 2 piece stock size kit. You can get a 2 piece kit in 10.75 made for you by fastbrakes though, I was quoted $975 per axle using wilwood powerlite calipers, which is a pretty killer price. So it'll probably be around $600 per axle for a kit that uses stock calipers.

Savington

iTrader: (31)

I have them. A little pricey, since they were never put into production, but a set does exist and I can make more. A little more than half a pound lighter than a factory 1.8L rotor. PM me for details.

guttedmiata

You have to know the specs for the custom job, but you probably won't find a better price than Coleman racing.

Savington

iTrader: (31)

The rings are easy. The hats are not. We have both

TNTUBA

iTrader: (1)

Not sure why you would be hell bent on the non-sport rotors. But here are a set of two piece sport rotors for $483.00 for the PAIR

Two-piece rotor (Slot) - MIATA MX5 (SPORT) REAR 01-05

and then just buy a set of the M-Tuned brackets for $130 and be done with it. Cheap, light and effective.

circuitmstr74

iTrader: (1)

Rules.
Its prob not worth it for a half a pound anyways

Savington

iTrader: (31)

Racing Brake rotors are utter trash.

TNTUBA

iTrader: (1)

That's not been my experience.

joyrider

iTrader: (8)

Sav seems more into track and you look like a real hardcore auto-xer. Different perspective I guess.

TNTUBA

iTrader: (1)

Possibly. Either way I wouldn't call them utter trash. I know of one guy who NDI'ed a set and found them to be superior to Stoptech parts......just saying.

And i have read TONS of positive reviews from guys running running them on road courses.....in much heaver cars than a Miata.

Savington

iTrader: (31)

They are made of shitty steel (not iron like a metal brake rotor should be) and they will destroy pads and thermal crack long, long before even the cheapest NAPA blank does. BTDT. Racing Brake blames it on the pad manufacturers, of course.

bbundy

If you seriously track them rather than autocross only you will find them to be trash. Not only are the slots horrible for pad wear and performance the material is garbage compared to cast Iron found in other rotors and it doesn't interact right with pads that work well on tracks.

monkeywinky

I've never used RB rotors - but their pads are utter trash.

It seems they've since changed their lineup, but years ago - they recommended me some pads that ended up crumbling and delaminating after a 15 minute session. They sent me a set of ET900's which they claimed would be the greatest thing I'll ever use with ungodly amounts of stopping power. They were lackluster and didn't last the day. Never bought another set nor will I try their rotors due to how terrible the pads were.

*disclaimer* this was on an evo X, but I had used carbotech and pfc on that car with no problems.

bbundy

With some internet searching As near as I can tell OEM non sport rear rotors have hats with an offset of 20mm and a 9mm thick disk 251mm in diameter. The hats that come with the wildwood version front big brake have an offset of 0.75”. A machine shop wouldn’t have a problem skimming off 0.95mm so.
From www.Summitracing.com
Wilwood 170-11682 hats $124.93 each
Wilwood 300-11653 Adapter Rotor/Hat Register Ring,2.17" Dia $13.82 each
Wilwood 230-12176 12 bolt kit hat to rotor $15.96
Custom made solid disc rotors from Home Page 6 on 6.25 need a drawing made it will require a step for fastener clearance $92.85 ea
Brake Rotor, 1/4 / 1/2, Custom, Solid Mount

So for ~$480 plus shipping and a few dollars at a machine shop you can make your own rear two peace rotor set.

bbundy

interesting the sport rotor I think has a slightly smaller offset 18.4mm and its thicker 10mm instead of 9 and a diameter of 275.5. off the shelf wildwood hat would need to be shaved a bit more to make a sport brake version.

bbundy

Coleman racing cast iron seems to be as good as it gets for rotor material. Less cracking than anything I have abused and friction characteristics with aggressive pad compounds is excellent.

afm

iTrader: (3)

Necro bump.

TLDR: Good find, @bbundy


(centering ring not pictured)

I put together a rear brake kit with these hats, and I had a few observations:

• The Wilwood 170-11682 hat has a 0.75" offset to the outboard face of the rotor
• The 18.4mm offset Bob quoted for sport rotors seems to also be to the outboard face of the rotor
• I used a .375" Coleman rotor, which is slightly thinner, so disc centerline moves outboard for the same hat offset
• The 2pc rotor is 6.99lbs, while a used sport rotor is 8.62lbs

All of this adds up to cause the centerline of the Coleman rotor ring on an unmodified 170-11682 hat to be ~.5mm (.0195) inboard of the centerline of a stock sport rotor. I designed this into the offset of my caliper bracket, but there are lots of other solutions.

I am pairing these with Dynapro Single (2-piston) calipers. The Dynapro Single uses a small pad (similar to OEM in volume), but PFC pads are available for $50 an axle. Running costs will still be good, pad changes will be ludicrously easy, and the piston area is a perfect match to the Sport calipers. My car is N/A and well under 2000lbs, so rear brake heat is not a huge concern.