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If you increase rotor diameter from 330 to 350mm but use the same Base caliper and pads, will the increase in rotor diameter not be covered by the pad? It seems you are increasing the rotor diameter but moving the caliper and pad further out leaving an area near the hat uncovered with pad. Are you really increasing swept area since some of the rotor will not be covered by pad? Am I missing something?
This would be my thought as well. Unless also increasing pad size, you are not utilizing all of the surface area gained by the increased diameter of the rotor (assuming same size "hat").
The disk brake ring is slightly wider on the 350mm S rotors and the pad is taller. So if you swap out the rotors and space the calipers you will end up with an area of the rotor that does not contact the pad.
I think Girodisk 350mm upgrade rotors have the narrower ring from the base car so they are better sized to the base calipers.
The disk brake ring is slightly wider on the 350mm S rotors and the pad is taller. So if you swap out the rotors and space the calipers you will end up with an area of the rotor that does not contact the pad.
I think Girodisk 350mm upgrade rotors have the narrower ring from the base car so they are better sized to the base calipers.
So swept area on the frontsis smaller with the Base vs S even though both have 350mm rotors? The hats must be larger in diameter on the Base than S? The rears have the same caliper as the S so you can use the S pads when you change rotors I believe.
So swept area on the frontsis smaller with the Base vs S even though both have 350mm rotors? The hats must be larger in diameter on the Base than S? The rears have the same caliper as the S so you can use the S pads when you change rotors I believe.
Yes and no. The base has a 330mm rotor up front. The S and GTS is 350mm rotor with a taller wider pad and the larger 6 piston caliper than the base.
So even if you upgrade to aftermarket 350mm rotors on the base, your swept area will be a bit smaller than the S, and the caliper/pad size smaller.
The rear rotors and calipers are the same as far as I know except for color. I am not sure about rear pad materials base vs S. I believe they are the same but haven’t checked recently.
The rear rotors and calipers are the same as far as I know except for color. I am not sure about rear pad materials base vs S. I believe they are the same but haven’t checked recently.
Rears rotor/calipers/pads are same between base and S. I upgraded the fronts (rotors/calipers/pads) to S and only changed the rear calipers since they were red to match the fronts in red.
Giro apparently has a smaller rotor (larger internal diameter) to address this. I have the J-Hooks and my pads do not cover it completely. Not a huge deal but it will show rust when you wash. I address it with a green scrub pad - comes off easy.
The primary performance advantage of only changing the rotor, and nothing else, will be to increase the size of the heat sink and lower peak temps achieved by the pads, rotors, and fluid during repeated hard braking. You won't notice a thing during normal driving, but stopping distances should be more repeatable if pushing hard.
When you install larger Girodisc rotors as you said you are only increasing the overall diameter. You are not increased the annulus of the pad.
What you are doing is creating more brake torque when you do this.
This makes a lot of sense, glad I read the thread. I've also seen that you can up-size the front S/GTS rotors (to 997.2 turbo size) incrementally and use spacers to put the calipers further out, increasing this kind of effect. Is there a Girodisc product that fits this? Do you recommend it at all?
Originally Posted by KNSBrakes
BTW we have an overstock of some 991.1 base Girodisc and also 991.2 S Girodisc if someone is interested in a screaming deal.
How loud are you screaming here - like cover my ears or FAA ear protection? DM me if you wish ... 2018 GTS whose front rotors have a bit of a lip but not "gone" yet...
The primary performance advantage of only changing the rotor, and nothing else, will be to increase the size of the heat sink and lower peak temps achieved by the pads, rotors, and fluid during repeated hard braking. You won't notice a thing during normal driving, but stopping distances should be more repeatable if pushing hard.
If I'm understanding this correctly, and this was my thought as well...regardless an increased rotor size will still lead to better overall cooling/heating dissipation? Please correct me if I am misunderstanding that.
The Rotor and caliper move out the equal amount(so pad contact stays the same). The Hat and mounting area is where is the size makes up for it. Significant heat reduction on track so far(as the 2 piece design is much more efficient at cooling) and the larger surface area to distribute the heat
See below photo, complete coverage on pad braking surface with Girodisc
Correct. I would say this is the first, and most cost effective upgrade, for someone taking their car to the track. Or perhaps for long mountain runs where heat build up is an issue. (As an example, descending Pike's Peak, even at tourist speeds, builds incredible heat!). Additionally, a 2 piece rotor design will shed more heat than stock rotors. Another heat reduction exercise is to remove the dust shields behind the rotor. This has a material effect on the ability to cool down the rotors. Also watch your pad thickness. The first half of their life they are very good heat sinks. Below the half way point its like the half life of nuclear material, they degrade quickly at a non-linear rate.
Heat is the number one enemy for brakes and the first issue to address, We have found that for skill levels up through intermediate, better cooling (managing air flow and rotor size) along with a proper brake pad and fluid is all most people need. And be sure to take a cool down lap. Pulling into the pits with hot brakes and no air flow will cook them faster than an egg on a hot skillet.
07-05-2023, 08:14 PM
Larger rotors for Base Carrera
