Whats y'alls opinions on my brakes?

[BeautifulAudi]

Hey guys, I have converted my 00 1.8tqm front brakes to s4 brakes and I have the stock s4 wheels to go with but I'm seeing a lot of people go different routes on big brakes besides the s4 stuff.
Did I do wrong in going with the s4 stuff?

[tar]

No urs are fine. Best part of those are uprights, you can always add 17/18z calipers and 330/356 2piece rotors later.

Just make sure yours are balanced as in s4 rears

[RagtagXMASTER]

I did the same thing to my a4. I have an 01 i put s4 knuckles And the oem hp2 calipers. Its a better base for upgrading than the a4 knuckles. Just like beautiful audi said we can later get 17/18z porsche calipers. Once they come down in price i would pick up a set. I did the conversion for $200 in parts.


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[BeautifulAudi]

Ok. Phew, I was getting worried. The rear s4 brakes are bigger than rear a4's too?

[redline380]

yes s4 rears are larger and vented. Stock a4 is something like 218mm, s4 is something like 256mm

[GrapeBandit]

lets play a game.

if 17z/18z on the front of a b5, you need ___________ on the rear to maintain the proper brake bias.

[redline380]

lets play a game.

if 17z/18z on the front of a b5, you need ___________ on the rear to maintain the proper brake bias.

I have 300mm rears on my 17z's and it brakes pretty well. I would say that would be a good start to pair rear brakes with such large fronts

[Davdraco1]

What caliper are you running with the 300mm rotor in the rear?

[GrapeBandit]

Those brakes are pretty and all, but they are not necessary.

remember, the limiting factor will always be your tires, not brakes.

if/when you have really good tires, and then you reach their limit, then its time for an upgrade.

[redline380]

What caliper are you running with the 300mm rotor in the rear?

B5 S4 with 034 brackets

Those brakes are pretty and all, but they are not necessary.

remember, the limiting factor will always be your tires, not brakes.

if/when you have really good tires, and then you reach their limit, then its time for an upgrade.

Yep, the 17z's are pretty. 75% of the reason I put them on. But I have learned to use them. I can brake way late now coming into roundabouts. That, coupled with my upgraded rear sway bay, and if I build boost just right, I am in for a fun time.

If you are referring to the 300mm rears as pretty, you are wrong. They are not pretty at all, but functional. But I have a feeling you were referring to the 17z's as pretty.

[DoesntCare]

Don't the 17z's weigh like 1/2 as much as stock brakes as well?

[tar]

lets play a game.

if 17z/18z on the front of a b5, you need ___________ on the rear to maintain the proper brake bias.

B5 s4 calipers, 300mm rotors, track or better pads than up front is what I'm planning.

[GrapeBandit]

redline, I was referring to the 17z as pretty. lol

[Davdraco1]

I was unaware they made brackets to get a bigger rotor with the S4 rear caliper.

[GrapeBandit]

ill leave this here

Can you lock up your tires? (ie ABS kicks in)

Do you have problems with brake fade?


If you answered yes and no, dont bother doing anything. Tires are the limiting factor.

[ricekikr]

^+1. Just get better pads unless you track or do multiple high speed braking.

lets play a game.

if 17z/18z on the front of a b5, you need ___________ on the rear to maintain the proper brake bias.

Bias probably 300mm. Bias is very vague though, tires suspension etc need to be factored.

Stock rears +18z feel more planted on hard braking from high speeds or trail braking vs 300mm rears. Stock were also on less aggessive pads (hps) than the 300mm (yellows same as front), so not apples to apples.

Bigger front brakes (with sticky enough tires + soft suspension) = more dive = less rear grip = less need for big rears.

[ElSabio182]

lets play a game.

if 17z/18z on the front of a b5, you need ___________ on the rear to maintain the proper brake bias.

Good discussion that'd I'd like to hear more opinions on. My "Current" setup is fine with regard to bias, and I think my "Long-term Future" setup will be OK. I'm a liiiiittle concerned that my interim "Soon" setup will upset the bias a bit. Dunno if I can mitigate that by running less aggressive pads in the rear than in the front...or if I'm over-thinking the whole thing.


Currently:
FRONT: A8 rotors/TT carriers (vented 288mm? with stock calipers) with EBC Redstuff pads
REAR: stock, with EBC Redstuff pads

Soon:
FRONT: unchanged - A8 rotors/TT carriers (vented 288mm?) with EBC Redstuff pads
REAR: S4 rotors (vented 256mm?) and S4 calipers with TBD pads

Long-Term Future:
FRONT: 17z setup with TBD pads
REAR: unchanged - S4 rotors (vented 256mm?) and S4 calipers with TBD pads


EDIT: I'll be running coilovers by the time the "Soon" and "Long-Term Future" setups are installed. Swaybars already installed. Maybe a couple track days per year.

[GrapeBandit]

^+1. Just get better pads unless you track or do multiple high speed braking.




Bias probably 300mm. Bias is very vague though, tires suspension etc need to be factored.

Stock rears +18z feel more planted on hard braking from high speeds or trail braking vs 300mm rears. Stock were also on less aggessive pads (hps) than the 300mm (yellows same as front), so not apples to apples.

Bigger front brakes (with sticky enough tires + soft suspension) = more dive = less rear grip = less need for big rears.

the stock rears + 18z may have felt more planted because less work was being done by the rear brakes, especially when compared to
a 300mm setup with good pads.

that feeling may have just been the 18z doing all the work with stock rears, more of a nose dive, while the 300mm rears doing more work gives the car a more balanced feel when braking hard

you said " Bigger front brakes (with sticky enough tires + soft suspension) = more dive = less rear grip = less need for big rears."
you dont want your front brakes doing all the work, and you sure as hell dont want to nose dive.

this is not directed to anyome in particular, but cant just go throwing on the biggest front brakes you can find with 76553893 pistons and not touch the rears, at some point, the rear will be doing like 10% of your braking power lol

[walky_talky20]

You can do 269mm rears just by getting C5 A6 4.2 rear carriers and using D2 A8 rear rotors. It's just a taller bracket for the same C43 (B5 S4) calipers. This will cost whatever 2 junkyard A6 calipers cost, which is not much.

300mm is doable as well, but requires a custom adapter bracket.

My suspension is fairly stiff (ST coilovers), so I don't get a whole lot of dive. The fronts (TT/A8 312mm) lock up pretty quick, so I wanted more in the rear to balance things. I got the largest OEM bolt-on thing I could come up with. Everything still clears OEM 16" Swings.

EDIT: Correct A8 rotor size is 269mm (not 280mm).

[ricekikr]

you dont want your front brakes doing all the work, and you sure as hell dont want to nose dive.

this is not directed to anyome in particular, but cant just go throwing on the biggest front brakes you can find with 76553893 pistons and not touch the rears, at some point, the rear will be doing like 10% of your braking power lol

Weight will transfer to front regardless (up to a point) of rear brakes. Stickier front = even more dive compared to stock tires (loses traction). Less weight on rear wheels = less grip. That's the reason you can't put 50/50% brake bias on front heavy car.



(for the readers passing thru) Piston count doesn't dictate braking force, piston area/pressure/rotor diameter/pad mu etc does.
Stock s4 rear + 17z is more rear biased than complete stock s4

For reference accdg to ecstuning link
Stock front+rear s4 = 2.6
Stock front+rear rs4 = 2.3
17z + stock s4 rear =2.3
18z + stock s4 rear = 2.9
(most 18z will run smaller 345mm rotors + smaller 17z pads. Bias would move towards rear compared to ECS 18z kit 352mm rotor + larger 18z pads)

Stasis = 2.5 / 2.9 / 3.0 (more track oriented company?)

Stoptech = 1.5 and 2.3 (more street oriented company?) 1.5 bias was recalled, no longer available.

Can't find the bias of a 18z/17z + 300mm rears. I remember comparing it to an E46 m3 when I was doing my brakes.

====

Anyways back to your game. There's no one ideal bias for all suspension/tires/weight distribution setups that can be done to a B5.

In my car, it just felt more composed with the stock rears in the street, where traction can be anything from 100% to Zero. But that doesn't mean the 300mm are bad, probably would even perform much better on the track where traction is more predictable.