GTR brakes

[323driver]

For those interested, from what I gathered, it's possible to run Mazda6 brakes with the GTR spindles. You can use either the smaller 11" discs found on the early 6 and base 3, medium 11.8" found on the 3 GT or 5 and the MS6 12.8 discs from the speed6. You need the discs and the caliper brackets, the calipers are apparently the same.

If anyone has access to these parts live to compare, please do.

[jay]

Hmm. I know someone with a speed6, I'll try and talk him into some comparative jackstand time. But if the calipers are the same I don't see the improvement, and downsizing the rotors doesn't sound too good either unless you're dragracing or autocrossing.

[323driver]

Stock GTR rotors are 10.9". Stock 6 rotors are 11.8" so it's not downsizing. Basically, the caliper is the same but the bracket is different so your caliper is located further. If you can compare with the speed6, it would be even better but i think 12.8 is way overkill, the rotors weight 22 lbs lol.

I also have FC aluminum 4 pots and they do line up with the GTR spindle but I need a rotor with a different offset to be able to use them. I'll work on that sometimes during winter, I might just fabricate an adapter and use the 11.8 Mazda 6 or Mazda 5 rotors with the FC calipers.

[jay]

I coulda sworn my rotors were 11.5, I better go measure em again!
Those fc calipers would be a pretty sexy upgrade. I know the guy who had my street car before I got it tried to use those and came up short with the whole offset thing. I've kinda shied away from caliper adapters, as this is an area I don't want trouble in...

[323driver]

The stock calipers are mounted on an adapter bracket, I don't see why a similar bracket professionally made for the FCs would be a problem. I have an MX6 caliper chilling around, I'll take off the bracket and see how it's done.

BTW, for the rears, the Mazdaspeed miata from 06 uses rotors of the same size, 11.1" but I need to take off my rear rotor and measure the offset to check if it's the same.

All my 4 rotors are shot and finding GTR replacements are a PITA.

[Crazy Drummer69]

Use Mazda6 (2001-2007) rotors and Mazda 323 V6 calipers/pads for stockish replacement parts.

[323driver]

What's a mazda 323 V6, no idea what you're talking about...

[Crazy Drummer69]

There were BG 323s offered with K engines around the world. Actually, I wonder how different the MX3 calipers/pads would be compared to the GTR since the chassis are similar and they came with a K engine too...
Here's a site you can get pads from: http://www.tinyurl.com/y95tcsx

[323driver]

That website is wrong for many models, the GTR uses bigger brakes than the 257mm standard BG discs. It should be KBD 845 which is the same disc as the Astina GT from NZ; good luck finding parts for it.

The MX3 uses standard BG stuff, nothing similar.

[Crazy Drummer69]

Hmmm I'm surprised the GTR is even listed now, it wasn't there before. I can't find the other site in my favorites anymore, grrr

[323driver]

BTW, the ms6 brake upgrade will work for 2WD BG guys if you can swap your stock spindle for a protege5 spindle. But IDK if you can use a protege5 spindle on a BG.

[jay]

GTR brake rotors, front,= mazda 929, rears = 98-02 626V6. Front caliper rebuild kit = '93-96 mx6 or 626. Dunno for sure about the rears as I have yet to need to rebuild those. GTR pads are the problem, some boutique Japan-based sites have them. Or, you call Porterfield and ask them to make you a set of R4S pads based on my pattern, tell em I sent ya...

[323driver]

Good info Jay

[redheddude222]

So how about this:

What if I got a set of GTR spindles/hubs, swapped in my 4-lug center thing, and used the ms6 calipers? The hardest part would be finding a 4-lug rotor with the right diameter/offset.

[therieldeal]

GTR uses a different (bigger) wheel bearing, i dont think the FWD hub would fit.