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Vendor GiroDisc 370mm Rotors for GM Brembo 6-Pot Calipers

girodisc-370mm.jpg

It takes a village to raise a kit. This one is TMC's very own. @Lukez pioneered the 6-piston CTS-V DIY for the Model S. Then @jesse_le prototyped a rotor with GiroDisc for the Model 3 and Y. These full-floating slotted GiroDisc rotors for the Model 3 and Y come in at 370mm x 34mm. This mirrors the rotor size on the Cadillac CTS-V, Corvette C7 Z06, and other GM performance vehicles allowing fitment of massive GM 6-piston Brembos. For comparison, the OEM Model 3 Performance 2-piece rotor measures in at 355mm x 25mm while the OEM 1-piece "Base" Rotor measures a paltry 320mm x 25mm.

The GiroDisc rotors differentiate themselves from other manufacturers with U.S. sourced iron and beautifully anodized U.S.-sourced 6061-T6 aluminum rotor hats. The hat is also 4mm thicker than OEM which helps clear the unique stepped hub of the Model 3 Performance and obfuscates the need for small wheel spacers. The GiroDisc is also a true 2-piece rotor allowing you to replace the rings without need to replace the hats.

OEM GM Brembo 6-piston Calipers​

The GiroDisc rotors allow you to mount OEM GM Brembos from a number of GM performance vehicles including the ATS-V, CTS-V, and C7 Corvette Z06. These are lightweight 6-piston monoblock aluminum calipers that are optimized for cooling, specified as "low drag", and are designed to fit under 18" wheels. They mount up to the OEM Tesla front knuckle by either drilling out your caliper mounting holes to accept M14 caliper bolts or re-threading the caliper to accept the OEM Tesla M12 hardware. The latter allows you to return the vehicle completely to stock.

viy-bbk-2.jpg


Another benefit of the GM 6-piston Brembos is a wide assortment of available brake pads. If you have ever searched for brake pads for the stock Model 3 Performance calipers you know that the selection for this seemingly proprietary caliper can be somewhat limited. The GM calipers feature a standard FMSI D1405 pad shape which opens up pad options from $64 Centric OE replacement street pads up to $700+ Ferodo DSUNO race pads.

Ordering​

As these are a relatively new offering, GiroDisc requires a minimum of 5 rotor pairs to make a production batch. Pricing is $1,200 per pair with free shipping to the continental U.S. There is an approximate 4 to 6 week lead time from the batch order for fulfillment. There is already some interest in the next batch and my hope is that the demand is strong enough for these to become regular stock at Emotive Engineering.

... and introducing... The EmotiVetted GM 6-Pot Bolt-on BBK​

giro370vettebbk.jpg

This is a full bolt-on affair which allows you to reuse your factory caliper mounting bolts (brake dust shield removal required).

Street Kit - $2,649
  • CTS-V Calipers - Silver (or optional Yellow) - re-threaded to accept factory Tesla caliper bolts
  • GiroDisc 370mm 2-Piece Rotors
  • DBA SP500 Street Performance Pads - copper-free ceramic pads, low-noise, and low-dust. Everything an OE+ street pad should be.
  • Spiegler Stainless Steel Brake Lines
  • OE GM Caliper Hardware
Track Kit - $2,899
  • C7 Corvette Z06 Calipers - Red - re-threaded to accept factory Tesla caliper bolts
  • GiroDisc 370mm 2-Piece Rotors
  • G-LOC R12 Track Pads - amazing pedal modulation, rotor friendly, at the expense of some noise and dust.
  • Spiegler Stainless Steel Brake Lines
  • OE GM Caliper Hardware



Not ready to go full on BBK? Emotive Engineering is an authorized GiroDisc dealer offering a full line of OE-replacement 2-piece rotors for your Tesla Model 3 or Y.
 
Last edited:

TwoK4drSi

Active Member
Apr 3, 2019
1,654
1,777
DFW
The C7 calipers have pistons of 30, 34, and 38mm. Overall area will be 0.08% less than the stock M3P pistons (so basically negligible difference). Bias will shift slightly forward due to the larger rotors. It won't be enough of a difference to create a truly measurable performance difference.
I like this math better
 

TwoK4drSi

Active Member
Apr 3, 2019
1,654
1,777
DFW
The spiegler lines lack a bracket. We do a lot of the AP essex kits and have to toss those lines out because there's no bracket. It's very hard to pull them off the factory lines as well. I don't know if they created new ones or not but might be easier to just get with goodridge or a company that is already making the Model 3 lines.
You can probably use a conduit clamp but need to ensure the O.D. Of the line. Relatively inexpensive and it’s padded.

 
The overall piston area is 55.0cm^2, almost identical to stock M3P pistons. I agree with what you say, brake bias will shift forward a tiny bit but it wont affect anything. I'd seriously consider this choice if it were something like 60cm^2, then we might have to load wider front tires to compensate for it. Thanks for the info!
The C7 calipers have pistons of 30, 34, and 38mm. Overall area will be 0.08% less than the stock M3P pistons (so basically negligible difference). Bias will shift slightly forward due to the larger rotors. It won't be enough of a difference to create a truly measurable performance difference.
 

emotiveeng

Member
Global Vendor
Sep 8, 2021
49
121
Belmont, CA
@yjypm I am glad you brought this up. Some BBKs are massive for the sake of being massive. I will sit down and do the math myself as well.

The third variable in static brake bias aside from piston area and rotor diameter is the coefficient of friction of the brake pad. That one is easier to adjust for with compound choice.
 
@KTomsky My apologies - I thought I had listed the specs earlier.

The front brake lines are side specific as the banjo fitting is mirrored.

Driver Side
Banjo Fitting: 029
Hardline Fitting: 711
Length: 588MM
Jacket Color: Smoke

Passenger Side
Banjo Fitting: 039
Hardline Fitting: 711
Length: 588MM
Jacket Color: Smoke

Rear Kit Part Number: 13.02.10700 with matching jacket color.

Though I haven't installed them on the actual car, I did a test fitment on my spare knuckle, and they look good.

I believe the OEM and even aftermarket SS lines are close at 533MM long, so it should be plenty at 588MM + the banjo elbow.

If you need more pics of my setup, please let me know and I'll go snap some.
 
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Fantastic. I'm so glad a TMC vendor decided to pick up inventory for the community!

@jesse_le did a lot of heavy lifting for us to get these made.
@drpheta and @vietfella ….looks like you are the only two that are running stock length lines. Notice any issues?

I didn't attach the clip to the knuckle cause the tension was too tight for my liking.
 

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Fantastic. I'm so glad a TMC vendor decided to pick up inventory for the community!

@jesse_le did a lot of heavy lifting for us to get these made.


I didn't attach the clip to the knuckle cause the tension was too tight for my liking.
Hey @drpheta - Appreciate the pic. Since you’ve been running this way for a bit, is there any abrasion between the jacket of the brake line and the wishbone part of that coilover tower?
 
I’ve gotten the yellow CTS calipers and I’m now looking for a place to powder coat them but I’m coming up with prices around $1200-$1500 for Brembo red (to match the rear) and a clear coat over a decal.

Anyone have recommendations that are less than that before I have a go at spraying it myself?
 
I’ve gotten the yellow CTS calipers and I’m now looking for a place to powder coat them but I’m coming up with prices around $1200-$1500 for Brembo red (to match the rear) and a clear coat over a decal.

Anyone have recommendations that are less than that before I have a go at spraying it myself?
Went the ERA2k spray route but bought them in red so didn’t have to spray as much.
 
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I’ve gotten the yellow CTS calipers and I’m now looking for a place to powder coat them but I’m coming up with prices around $1200-$1500 for Brembo red (to match the rear) and a clear coat over a decal.

Anyone have recommendations that are less than that before I have a go at spraying it myself?
That’s crazy expensive. I got my factory calipers (all four) powder coated for around $400.
 

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Sam1

Active Member
Sep 11, 2019
1,794
1,870
NV
I’ve gotten the yellow CTS calipers and I’m now looking for a place to powder coat them but I’m coming up with prices around $1200-$1500 for Brembo red (to match the rear) and a clear coat over a decal.

Anyone have recommendations that are less than that before I have a go at spraying it myself?

Something is wrong with that, just last year I paid $600 total for a set of four 18" wheels to be stripped and powder coated with a 24 hour turnaround time.
 

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