Rear Brakes to Front Brakes Activation

241 Views 7 Replies 4 Participants Last post by gapi, 2 d ago

gapi

Discussion Starter · 7 d ago

I recently re-shod the BR9 brakes on my 2013 R/T, with PFC pads and rotors.

The braking is noticeably better from the MOPAR Semi-metallic on Raybestos Police Rotors. Worth the trouble better.

One thing I noticed when testing a few hundred miles after bedding is either the rear brakes kicking in a little delayed or the pads and rotors loving the heat increase.

The test is on a long declining I-75 off ramp with no one forward of me all the way to the light, to take downshifting out of the mix I go into neutral, going 70mph I apply aggressively, not looking for ABS hard, but seat-belt tightening none the less.
Just as I'm about to give them maybe a little more more braking kicks in. Its great, not a complaint, its why I went to neutral because I felt this may be downshifting.
I did a full bleed, including raising the rear 10-inches as per shop manual, there was no air.

Any logic to this? Are they per-portioned to be a touch behind in the rears?
Great pads, I'm sure the Rotors are too. Cold bite, and big toe braking around town. Rear disc sweep is full, not like OE.
Fantastic firm pedal. The rotors need no oil for shelf life. They are shown as they came out of the box. Everything is USA made.

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Hemihackman

· #2 · 6 d ago

They are better than OEM metallics? I wonder if coefficient braking kicks in. A little more pressure and they grab a lot harder.

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gapi

Discussion Starter · #3 · 6 d ago

I think its either intentional because rears too soon especially in the wet could skew the cars line of travel or maybe ABS is seeing it needs to catch up to the big boys up front?
Its quite welcome and enjoyable for sure, I just want to know the logic behind it.

Yes, much better, and rotor friendly, LEO garages are getting 3 pad sets on rotors. Steel wool per say is in OEM metallic, PFC are carbon metallic. They dust less, but do, and it washes off easily not turning red like semi-m.

I wish I could tell you guys the metallurgy make up of the rotors but its a trade secret. PFC also makes brakes for racing organizations. No crosshatching, no mill cuts for balancing, they come off machined balanced. Even the hats are hardened to a spec. That finish on the shot of the rear rotor is just after bedding. They are slicked off now.

This is how the OE BR9 rear pads sweep.

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Spud66

· #4 · 6 d ago

I doubt there is any delay mechanism in applying the rear brakes as part of the system. It is possible that the preset proportioning is heavily biased towards the front to prevent an initial lock up at the back, and that the system starts applying more braking force on the rear. But even this I doubt, just because such a system would necessarily mean leaving some braking performance on the table, since the rears aren't working at peak power until later in the stop. Given that this is a new phenomena for you, it's very likely the pad material - high performance pads are designed to offer more braking force under hard use. Put another way, the hotter you get them (up to a point), the more friction the pads have. So they brake harder later in the stop, given consistent pedal pressure.

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gapi

Discussion Starter · #5 · 5 d ago

Thanks. For all I know it could be all four corners, I run these pads on my 05 Silverado fronts also and they are great. The rears are drums.

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CE9311

· #6 · 2 d ago

If Its anything like the braking bias on the LH platform. Rear and front under light braking will both engage same, and the harder you press on the pedal the more bias goes to the front in equal proportions to prevent swing around.

I do not brake pads that perform better hot than cold will act just like what you said. More braking power felt regardless of pedal movement as heat builds. The Hawk HPS pads on the Eagle I have behave like this.

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Spud66

· #7 · 2 d ago

I was feeling a little light braking pulsing on my full Wilwood set up with BP-10 pads, so I went out to bed the pads again and clean the rotors of any deposits. I felt the braking get heavier further into the stop, even getting into the ABS once without trying to add more pedal pressure. Love these brakes.

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gapi

Discussion Starter · #8 · 2 d ago

Thanks Guys, Brake Bias aside, I think it is also when they get to a temp they really like. I had some cat & mouse chase running in the Salacoa area noticing soon after while they were still hot the pedal was more sensitive in those few minutes in neighborhood driving.
Anyways, in short, I knew the pad rotor combo were going to be somewhat better, and Krautmaster from the BR9 upgrade thread on the other forum reported the same just on the pads and other brand rotors, but I didn't expect to be WoW'd like I am.

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