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Yes, it was initially thought that the pad material had melted on unevenly and this was certainly the case to an extent as you could see it. In addition to the shudder, I also had quite a few odd occassions where the pedal would go soft and become quite long, although I didn't notice any fade and not sure if it was simply the ABS cutting in or not. New race brake fluid and another track day later the symptoms did not improve.
That's kind of concerning. In my experience the ABS coming on will not cause the pedal to go soft. When the ABS kicks on, you'll feel the car hop a bit, but the pedal should stay firm. Which fluid were you using? I had this happen with stock fluid, then I upgraded to motil 550 and had it happen only a little bit after a long session, then I upgraded to motil 660 and haven't had it happen since.
I was originally using the OEM fluid so the long pedal may have been the fluid over heating but the strange thing is the brakes would still grab at the end of the pedal but was concerning. I was told it could have also been the ABS pulsating. Maybe it was both.
I changed to Castrol SRF but haven't been back to that track to really test the brakes. However, the shudder on the rotors didn't improve after two more track days on another course so that's when they were machined and the shop I'm using now put in the Motul 700 fluid.
In any case I suspect the OEM fluid is not up to track work in warm conditions and courses that are hard on brakes.
I used SRF with OEM rotors and DS3.12 pads last season. Great, fade-free performance, but lots more pedal travel once the brakes warmed up. Cold, and on the street, pedal travel was about the same as OEM. Your experience isn’t unique.
Just to update, my Girodisc Rotors have come to a premature end. Not saying it is a fault of the rotor but perhaps the fact that my car is 90%+ used on the track in time attack/supersprint so perhaps very hard on brakes.
Nevertheless these rotors probably lasted one and a half pad sets, although you can see from the photos below I left my last pad set (DS3.12) a little too long so that probably also did not help the rotor.
Essentially the pads have worn very unevenly and carved almost a 2mm groove along the inner circle of the rotor compared with the outer circle due to the bottom of the bad becomming thicker than the top of the pad.
What I've learnt is that pads wear very unevenly and to check the pads more regularly. My workshop also said I should rotate the pads. Not sure if this is normal or not so hopefully others can chime in.
Here are the photos of what's happened so maybe others can also learn from my experience. You can really see how uneven the pads have worn.
These are the front DS3.12 pads:
And the rear DS3.12 pads:
This shows the horizontal taper:
And now the vertical taper where the pad is thicker at the bottom than the top, which is what's worn the inside circle of the rotors:
This photo shows the inner circle of the front rotor worn away:
Those pads are certainly shot, but I would still use those rotors for quite a while. I stop with the rotors when a crack extends to the inner or outer edge of the braking surface.
I don't know why you are having such uneven wear with the pads. The wear marks on the rotors suggest that they may be a little small for the job. Perhaps other pad companies' pads have different dimensions.
Just for reference, I use PFC 11. I get very even pad wear, and do not ever rotate the pads. They are considered an aggressive pad. I get 12-15 weekends from a set of Girodisc rotors, and admit that I probably change them before it is necessary.
Thanks, I thought I could also use the rotors a bit longer but I guess the issue is that the rotor surface is now uneven from outside to inside due to the uneven pad wear, you can see the grooves have disappeared towards the inner part of the rotor, particularly in the first rotor photo. I'd say the outside part of the rotor is fine but the inner circle part is well worn. I assume this will have a negative effect on braking performance due to the uneven rotor surface. Seems the life of Girodisc rotors does vary considerably between car types and driving conditions.
Here is a photo after an easy track session and rotors on the car. I'm still using OEM pads but did bed them in.
I just put Giordisc rotor on my GT4. Mostly a track car, also using factory pads.
Any advice on the procedure to get the Brake dash light off?? …or do I need to go in with and ODB reader to reset? Thanks!!
I just put Giordisc rotor on my GT4. Mostly a track car, also using factory pads.
Any advice on the procedure to get the Brake dash light off?? …or do I need to go in with and ODB reader to reset? Thanks!!
Sorry I have no idea as my workshop does my brakes for me. I'd more be concerned why the dash brake light has come on? Usually that is a wear indicator on the pads?
12-31-2020, 02:20 PM
