Martin Bishop

I understand a few people are running yellow front and black rears. I have RS29s in the front with DeMan slotted fronts and Rear RS14s. The Fronts have 2 days DE at TWS, with 3 sessions on the Deman rotors. The rears RS14s have 3 sessions, which were trailered to the track, bedded in as normal. I am running new Motul fluid, on an alignment that is as new as the fronts. I am struggling quite a bit with the RS14s and do not like them despite what others may have experienced. The RS14 squeaks even with the pads hot as can be, and the car feels unstable under hard breaking.

I have run yellows in the past and always quite happy with this setup. Can anyone suggest what I might be doing wrong as I am arguing with Craig Carlann from renn store with him trying to convince me this is a better setup than yellows all the way around. I originally called him and told him I wanted RS19s and ended up being talked into getting blacks even though I told him I did not want them.

Does anyone have any suggestions or am I doing something wrong as I do not like this setup at all

mooty

it's a personal pref thing.
my friend runs 29 front 14 rear loves it and much faster than i am
i did the same set up, i hate it. it bites too fast for my taste. i like the rear to drag a bit. so i went back to RS29 all around.

Bob Rouleau

Martin - I ran RS 19 or 29 in front and 14's in back on my 996 GT3 and they worked fine. No squeal. With 19's or 29's all around I wore out front rotors every 8 to 10 track days. I then added Cup brake ducts and went to the RS 14s in back. Did 30 days on my front rotors and finally wore out a set of rear rotors. Brake balance was improved. Can't say why you are not seeing the same benefit. Are you sure the rears are properly bedded? Instability under braking is usually a rear toe in issue. To little toe in and the car will be a handful under hard braking. The rear toe on a GT3 is very fragile. Anything can upset it unless you go to racing toe links. They are a very worthwhile upgrade. I like the ones from TRG.

Best,

Crazy Canuck

I use what Bob suggests. RS19 front and RS14 rear w/cup ducts and TRG toe links.. I like it although some don't like the RS14s on the back.

My brakes last and last but I'm not especially hard on brakes.

va122

Is your TC on? Doesn't it use the rear brakes?

LVDell

Martin, are you doing this with the car in your avatar? The 997 does not have the same braking characteristics (and bias) that the 996 does. That might be your first problem.

What Bob stated is exactly what I would echo wrt the 996. I tried every pad combo and with Pagid the 19/29 front and 4 rear was the best. That is until I moved over to PFC

997gt3north

I was about to post the same thing. If the car is a 997gt3, the rear brake bias is already at it's MAX imo and you do not want any further rear bias unless maybe? you are running a +2 size front tire (265 Hoosier) and somehow it has thrown the balance off.

If it is a 996, everyone has a different braking style and I would say just go with what works for you - but given that Porsche increased the rear bias of the 997 vs the 996, there is obviously some improvement that is available but as the above posters have pointed out, as you get closer to a "rear bias" the car can gets closer to unstable if things are "off" - i.e. alignment (rear toe) or poor front pad cooling which would cause the rear bias to further increase pushing the car past the edge thus making it unstable (everything is a system and has to work together - small changes sometimes can have big consequences)

Martin Bishop

996.

I am still running Nittos. I plan on putting Hoosier slicks on today to see if that makes a difference. Alignment was just done 3 track days ago, so I do not think the Toe is the issue. Plus alignment was not changed and was perfect before changing the rears.

I will take a look at my ducts. I have another set and mine are a little beat up from going on/off trailer.

These squeal like a pig ALWAYS when touching the brakes. I even pushed them as hard as I could to get them to shut up but they still squealed. It is driving me mad.

The fronts I am using Slotted and the rears OE, so there might be some issue there that may account for my difference.

LVDell

Running the Nitto "could" have been one explanation. I routinely found that I was exceeding the traction of the Nitto with the RS14's. Once I ran the Hoosier R6 and then the Yoko slicks I did not have a problem.

As far as squealing, what is your braking style? Are you sure you are even getting them up to temp? Try re-bedding the pads.

KOAN

I am running the same combination of rotors, and don't have any problems, so I don't think the problem is in the rotors. I'm using PFCs though. Aside from the squealing, I think you'll find you are braking much better when you get stickier tires. I agree with Dell.

Martin Bishop

Thanks Dell. That is an interesting thought that I will have to explore. I will also try to play with a bit different braking.

I will post later this afternoon how things turn out. It is a bit cold today so might not be a able to get tires up to temp, but we will see

LVDell

How cold is cold? I was able to get my tires to temp in low 40's ambient temps.

multi21

Martin,

The blacks will squeal way more than the yellows. It's only when on the track and very hot that the blacks won't squeal. Don't worry about the sound unless it bothers your concentration while on track, but try to block that out, it's normal.

My concern would be more directed toward the feel of the car. All I can say is that we all have different driving and braking styles and yours might be different than those that have posted.

Martin Bishop

It seems that I am getting too much bias with the Blacks. I can get the back to wag under heavy braking. They squeal way more than yellow I completely agree.

I plan on having them removed and replaced with yellows. let's see how good craig at Renn Sport is about this as I called him told him I did not want squeaky brakes, or to change the dynamics of the car. plus I told him over andover I wanted yellow until he talked me into trying the blacks. We need to see if it was a mistake of going with Renn Sport, or just a mistake to be talked into something I knew I did not want.

Hopefully he will work with me on this or just sell me yellows at cost or something as I knew I did not want these.

Martin

Martin Bishop

Turned out to be low-mid 50s when I finally got out. It was 38 this morning and I almost did not go