Anyone using Girodisc's rotors?

Discussion in 'GT350 and S550 Technical Forum' started by honeybadger, May 16, 2018.

  1. honeybadger

    honeybadger TMO Intermediate

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    Hi all -

    Planning for some big trips to some very high speed tracks this summer and working through my list of consumables. I'm exploring brake options before I commit and am wondering if anyone has tried the Girodisc rotors for heavy track use? Wanted to see if anyone has some real feedback/data points to share?

    I'm currently testing out Raybestos ST43s on the OEM rotors. When I used G-Loc R16s last year, the OEM rotors last 15 track days before they were toast. But that was before R compound tires, which are looking like they might cut the life by 1/3rd or so.

    I have 8 track days scheduled within a 2ish week time period that will be hell on the brakes and am looking for something maybe more durable. Thoughts? Anyone have real feedback?
     
  2. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    My CorteX cambered rear axle comes with GiroDisc rotors and they seem to be quite stout.
     
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  3. captdistraction

    captdistraction Not necessarily the Stig

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    I am running them and so far so good. They dropped 10lbs a side for me (380x32) but have enough mass to deal with the heat I generate under braking. Have 8 days on them so far and just starting to see slight heat fatigue cracking (I’d estimate about 1/3 life). Running R18 pads in w2w race use.
     
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  4. VoodooBoss

    VoodooBoss Rick Moderator

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    To me this is a cost factor question. You can buy 2-3 sets of rotors for one set of replacement rings. I’d wait to see if the GT500 has slotted rotors as rumored.
     
  5. barspen

    barspen TMO Advanced

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    I'm planning on buying them soon, although I wont get them on the car until it starts to cool off in the desert southwest (Oct). Moving to G-Loc R12 on the fronts and plan to swap to GS1 between events.

    One reason I really like Girodisc verses others, they have spring clips on the hats that keep the noise level down for a floating rotor. Might not be an issue for a dedicated track cars, but on the street, sounds like 'full floating' can get annoying.
     
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  6. honeybadger

    honeybadger TMO Intermediate

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    This is definitely an option I hadn't thought of. I thought I read rumors that the brakes were going to be bigger on the GT500 since it was using 20in wheels, so I didn't really think of it as an option. I was mostly exploring if Girodisc rotors would improve longevity and could handle abuse better enough to justify the cost.

    So far it seems most have assumed that they aren't worth the cost over OEM on the GT350 (probably rightfully so). Am hoping someone who is running them hard on track can provide some feedback to either direction.
     
  7. honeybadger

    honeybadger TMO Intermediate

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    Good to know they're holding up well to your racing applications. I've heard good things - definitely tempted.
     
  8. Drlee50

    Drlee50 TMO Advanced

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    10 or 15 track days on stock rotors is great ! Hard to beat that for the price. I get 1 weekend , maybe 2 on the boss 302. I run slicks and stock abs module tho. Hoping the 302r abs module helps. I run g-loc r18. I'm sure your larger pads and calipers help a bunch.

    Sent from my LG-H932 using Tapatalk
     
  9. VoodooBoss

    VoodooBoss Rick Moderator

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    I’ve used Stoptech two piece before, which are very similar to the Girodisc, and I expect the Girodisc to last longer than stock GT350 rotors. I’m not sure the brakes are bigger on the 500.
     
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  10. OPMustang Tim

    OPMustang Tim TMO Race

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    A majority of our GT350 Customers have swapped to the Girodisc on the GT350. The cracking on the OEM ones is usually the main reason. The other reason is the holes will cause scalloping in the rotor when running an aggressive pad. Holes tend to act like a cheese grater on a pad. This causes odd wear patterns in the rotor and obviously shortens the life span of the pad. The one 'benefit' of the holes is once the rotor gets scalloped you now have more effective braking surface area due to the hills and valleys. The slotted Girodisc while still provided some pad aggression it is not nearly as pad agressive as the holes. There is some question as to the OEM rotor material at elevated temperatures (Slicks, COTA, R16-R18 pads) being capable of handling the conditions leading to accelerated wear but mostly We feel the 'marketing' holes are to blame. The Girodisc also does remove some weight (not a huge amount) despite the size of the ring but also provides a better air pumping action due in part to the ventilation vanes which manages heat more effectively.
     
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  11. honeybadger

    honeybadger TMO Intermediate

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    Thanks for the insight, Tim! Any more specific insight on the longevity of Girodisc rotors compared to OEM?

    I'm actually moving to Texas and will be running COTA a couple of times a year. Also should mention that the road trip I am taking will include Road Atlanta, VIR, Road America, and Watkins Glen - the brakes will see some serious abuse. I would only expect 6-8 days out of the rotors (assuming no mistakes, bad wear, etc.) in those conditions.

    Unrelated - have you seen or heard of anyone adding proper brake duct cooling for the 350 yet?
     
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  12. VoodooBoss

    VoodooBoss Rick Moderator

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    Drilled rotors suck. Why oh why do manufacturers continue to use them? Anyway the GT500 is supposed to have slotted rotors and will hopefully be able to replace the drilled rotors on the GT350.
     
  13. CompetitionMotorsport

    CompetitionMotorsport What you need, when you need it, no excuses.

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    We have been using Girodisc rotors for years in Porsche racing with excellent results. We have many customers using them on cars as varied as the Mustang Boss 302, Corvette C7 Z06 and Z07 (ceramic brake replacements), Porsche GT3/GT3RS and Cayman GT4, McLaren 650S, and Ferrari 458/488. Girodisc is working on rotors for the current GT350, we should know soon when they'll become available. In terms of longevity, cooling, and braking performance we have found no better rotors than Girodisc. Brembo and AP Racing have also served us very well, and Brembo especially has become more cost effective than they had been. But we still sell more Girodisc than anything else, and use them more often on our own cars than anything else.
     
  14. bpracer

    bpracer Mark

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    I thought the pictures of the 2019 GT350 rotors had no holes. But you can't trust pre-production photos
     
  15. VoodooBoss

    VoodooBoss Rick Moderator

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    There's a photo out there with factory slotted rotors but they don't appear to have made the cut. And I forgot to ask about that yesterday. :rolleyes:
     
  16. ChopSui

    ChopSui Mike

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    Wait, what happened yesterday?
     
  17. VoodooBoss

    VoodooBoss Rick Moderator

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    I was in Dearborn and at Watson Racing.
     
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  18. JeffV8

    JeffV8 TMO Race

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    Did they take you out back into the shop?
     
  19. VoodooBoss

    VoodooBoss Rick Moderator

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    Yes, very impressive operations!
     
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  20. Black Boss

    Black Boss TMO Addict

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    Disclosure: I'm hard on brakes. Drilled OEM front rotors are cheap, but only lasted 5-7 track hours for me. GiroDisc last an average of 17 hours. Economically, Girodisc are a little less expensive, but the real pay back is way less maintenance.

    2019 GT350 has plain rotors shown in photos.
     
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