BBK Kit Owners. Did rears make difference?

[dazzabb]

Well after talking myself into, then out of, then finally back into buying a BBK I settled on a Brembo 380mm front package only.

I'd like to hear from guys that have bought a FRONT BBK and then at a later stage bought a REAR BBK.

Did the rear kit make much difference?

Knowing what you know now would you buy the rear kit again?

Any other info that might be useful?

[cen]

would love to find out too whether the rear ones are more for aesthetic.

[lsal]

^^

[spdy330]

I don't track my car but I can tell you that I noticed no difference from OEM with my daily driving other than they look fantastic.

[TurboBimmer]

For the looks, yes

[klammer]

I think they're rather unnecessary, but that being said I have a full BBK and as a point of reference go through almost 3 front pad changes (more like 2.5) before I have to change my rears. Am sure it does help a little, as my brakes are monsters and I am routinely catching cars in the braking zones (even miatas and s2k's) and think that may have a little to do with the full kit. It's mostly bling, but think there's a small benefit (maybe) when you start pushing the limits...

[dogbone]

I bought a set of AP Racing brakes, and due to a long story, the fronts and rears arrived at different times. I put the fronts on first and tracked those several times before the rears arrived.

On the street, the rear BBK is simply a cosmetic addition.

At the track, it is nice to have all four corners, but not absolutely necessary. With my stock brakes, I was experiencing pretty bad shaking on the track, plus all the other issues you get with brakes, pads and fluids not up to the task. When the front BBK went on, ALL of the shaking disappeared and I've never had a brake issue since----pretty amazing. But the front was so powerful compared to the rear, that the nose-dive was pretty significant. When the rear BBK went on, the car didn't nose dive nearly as much. It squatted and became more predictable on super hard braking. That was a nice revelation. (Important note: a proper alignment is necessary to ensure the car is predictable on hard braking. A friend with a BBK was complaining about the car being squirmy on hard braking. I suggested getting the alignment checked. Turns out the rear had significant toe out which is bad for hard braking stability. All the squirminess went away after the alignment was fixed.) As Klammer said, with a proper BBK setup on our cars, I can catch all kinds of people while braking. In fact, you almost have to worry about rear-ending someone you were chasing because you can come into those corners so hot and not have any issues.

Now, perhaps you could put a more aggressive pad in the stock rear caliper to help balance a BBK in the front, but my thought on that is----you aren't going to want to leave a hardcore pad in the rear caliper when the car is on the street. It's going to squeal and chew up your rotor. So, if you're committed to changing pads between street and track, which you ABSOLUTELY should be, then changing pads on the stock calipers is kind of a pain in the ass. So, you'll be solving several things by going with a rear BBK----more powerful rear braking, easier pad changes and looks way better.

My pad setup these days is Cobalt Friction---XR3 front and XR2 rear. The XR3 is a medium torque pad and the XR2 is lower torque. This setup has been working very well.

[Kwando]

Aesthetically, the side profile will look more balanced.

[radiantm3]

I heard only front BBK will cause endo's which are awesome.

[pkimM3r]

Originally Posted by radiantm3

I heard only front BBK will cause endo's which are awesome.

dude endo with some steering input! BADASS!

on serious note.....has anyone ever considered moving the front calipers to the rears with a custom bracket (and either a drum for the ebrake or a separate bracket for this?)

[///M Ryder]

Your question is the reason I did front only. I've driven cars with both and I can't really feel enough difference to justify the money spent. But with that being said, I have SS lines and Stop Tech performance pads in the rear. And since I knew I wasn't going to change the rears I opted to get black as my color so that it still matched the rear. I also got the 365 kit so that the brake bias is still pretty much the same...............Phil

[dazzabb]

Some good informative replies thanks, I won't be adding the rears.

pkim1079: Moving the front calipers to the rear, very interesting idea! though I somehow doubt it would be very easy.

[evilspiritM3]

I thought that the rear caliper/rotor on my Performance Friction setup helped settle the rear under heavy braking, but I can't say that wasn't just part of an over all better braking situation with the whole kit.

[mid-corner fun]

Front BBK & rear OEM here with same track pads all around (DTC70s) for track days.

I don't have an apples 2 apples comparison unfortunately, just 1 session on a friend's M3 with front & rear BBK but unfortunately he was running stoptech street rear pads. Very predictably my setup had a more balanced brake bias with slightly more stopping power. Also cooling the rear brakes and rear-brake-fade is usually not such a big concern.

Sure, I don't like having to remove the rear calipers to get to the pads but IMO that's not worth the $$ for the rear BBK. Besides, I don't do individual corners, I raise 1 side at a time so swapping a rear pad adds 10mins tops to the process.

Now if only someone could predict which way the damn rattle clip is going to fly off... I bet that's the real reason BBKs exist

[armyav8tor]

Originally Posted by ///M Ryder

Your question is the reason I did front only. I've driven cars with both and I can't really feel enough difference to justify the money spent. But with that being said, I have SS lines and Stop Tech performance pads in the rear. And since I knew I wasn't going to change the rears I opted to get black as my color so that it still matched the rear. I also got the 365 kit so that the brake bias is still pretty much the same...............Phil

+1, got my PFC BBK running PF01 pads front only with stock pads in the back for a long time and the car performed fine. Switched to Stop Tech performance pads in the rear same as you for the last few HPDEs and felt no difference in stopping performance. The front brakes does all the stopping, never felt any instability. I brake pretty hard, and like to trail brake. Now, I don't know if suspension and tire setup would play a part in this equation. I'm running OEM EDC lowered on Eibach springs and very good street tires.



I have not experienced the nose dive/ brake balance issue that dogbone referenced even though it makes sense. This is with my front pads being one of the most aggressive compound available on the market and the rears running OEM and now Stoptech pads.

[Hujan]

Originally Posted by armyav8tor

+1, got my PFC BBK running PF01 pads front only with stock pads in the back for a long time and the car performed fine. Switched to Stop Tech performance pads in the rear same as you for the last few HPDEs and felt no difference in stopping performance. The front brakes does all the stopping, never felt any instability. I brake pretty hard, and like to trail brake. Now, I don't know if suspension and tire setup would play a part in this equation. I'm running OEM EDC lowered on Eibach springs and very good street tires.



I have not experienced the nose dive/ brake balance issue that dogbone referenced even though it makes sense. This is with my front pads being one of the most aggressive compound available on the market and the rears running OEM and now Stoptech pads.

Off topic, but your car looks badass.

[armyav8tor]

Originally Posted by Hujan

Off topic, but your car looks badass.

LOL, thanks! OEM baby!!!!

[Sebringjetta]

Originally Posted by dogbone

I bought a set of AP Racing brakes, and due to a long story, the fronts and rears arrived at different times. I put the fronts on first and tracked those several times before the rears arrived.

On the street, the rear BBK is simply a cosmetic addition.

At the track, it is nice to have all four corners, but not absolutely necessary. With my stock brakes, I was experiencing pretty bad shaking on the track, plus all the other issues you get with brakes, pads and fluids not up to the task. When the front BBK went on, ALL of the shaking disappeared and I've never had a brake issue since----pretty amazing. But the front was so powerful compared to the rear, that the nose-dive was pretty significant. When the rear BBK went on, the car didn't nose dive nearly as much. It squatted and became more predictable on super hard braking. That was a nice revelation. (Important note: a proper alignment is necessary to ensure the car is predictable on hard braking. A friend with a BBK was complaining about the car being squirmy on hard braking. I suggested getting the alignment checked. Turns out the rear had significant toe out which is bad for hard braking stability. All the squirminess went away after the alignment was fixed.) As Klammer said, with a proper BBK setup on our cars, I can catch all kinds of people while braking. In fact, you almost have to worry about rear-ending someone you were chasing because you can come into those corners so hot and not have any issues.

Now, perhaps you could put a more aggressive pad in the stock rear caliper to help balance a BBK in the front, but my thought on that is----you aren't going to want to leave a hardcore pad in the rear caliper when the car is on the street. It's going to squeal and chew up your rotor. So, if you're committed to changing pads between street and track, which you ABSOLUTELY should be, then changing pads on the stock calipers is kind of a pain in the ass. So, you'll be solving several things by going with a rear BBK----more powerful rear braking, easier pad changes and looks way better.

My pad setup these days is Cobalt Friction---XR3 front and XR2 rear. The XR3 is a medium torque pad and the XR2 is lower torque. This setup has been working very well.

funny you mention the car being "squirmy" under hard braking.... i changed my fluid, put on pfc 8 pads front and rear then ran at laguna....under hard braking the car would squirm pretty bad....went and got a alignment ran at laguna again and the car did the same thing...makes me wonder if the braking is to much now for oem susp.....

[Sebringjetta]

Originally Posted by radiantm3

I heard only front BBK will cause endo's which are awesome.

[FR01]

Been running AP BBK on the fronts now for almost 2 years and probably 12-15 track days. I've been gradually going to more track oriented pads on the rears. Running HP+ the last two pads changes; more due to timing of last min track days. I gotta say this last day at Laguna I had my fastest avg times and I noticed significant nose dive and a bit of shimmy into T2 & T11. I had the thought at the time of going BBK in the rears to help balance things out a bit. Also, I don't think the OEM rubber bits/boots and other components will hold up as my braking gets harder with harder track pads. Granted pads are cheaper with OEM rears and changing can be down to 15mins as a previous poster said.

Not sure how heavy of a braking track you're going to but I'd consider the temps and longevity as I am as well.

Brand new HP+ rears in one day at Laguna (previous owner painted my calipers a matching DY, now burnt orange).

[Richbot]

I went with Trophy 355 fronts and will replace the rears with the trophy 355 kit when I get a brake pad wear light. Save a few pounds off the car, get better braking, and the damn OEM parts are $700+ if you do it yourself, so you get a "discount" if you upgrade when the rears wear out. Mod rationalization ftw

[grantmax]

Listen to Dogbone, he's a cool dude.

The rears looks so cool, but do so little. Save money and go Alcon!