Any thoughts on how brake bias can be adjusted on the S4 ???

FixedWing · 12-29-2005, 05:55 AM

The brake bias on the S4 is heavily biased to the front of the car. When we add big front brakes, we only make the situation worse. Normal practice is to increase the size and/or advantage of the rear brakes (S8 rear rotors or RS4 rear calliper & rotors).

I would like to avoid changing the rear brakes if I can because I will continue to use 16 inch wheels in the winter. That means I will need to swap front callipers seasonally. I'd like to avoid also having to swap rear callipers if I can (the RS4 brakes will only fit under 18 inch wheels).

So does anyone have any ideas on how the brake bias can be adjusted other than by mechanically changing the brakes?

Stephen

WindyCityS4 · 12-29-2005, 06:00 AM

fit under 16's. There is a lot of clearance back there.

Hal_TT::CBP · 12-29-2005, 06:02 AM

under the 17" Avus wheels. There are others I think(4 piston kits mostly) that do the same... you'll have to look at wheel clearances though, don't recall.

WindyCityS4 · 12-29-2005, 06:03 AM

FixedWing · 12-29-2005, 06:08 AM

Really needs the RS4 rear brakes to do that. And this is likely to be the route I will end up taking.

Stephen

FixedWing · 12-29-2005, 06:09 AM

WindyCityS4 · 12-29-2005, 06:15 AM

I agree with you. But since I needed rotors for the rears anyway, it eneded up being a $150 mod.

I don't recommend it to anyone that wants "kit fitment". It is not a direct bolt on. The tweaking is very easy and fast, but still needs the use of washers to space out the carrier.

davenew · 12-29-2005, 06:17 AM

I'm sure the smallest alcon kit brakes and dissipates heat better than stock brakes. I don't think the slight leverage advantage of the bigger rotors is worth the hassle of wheel fitment. Not to mention, the larger the rotors, the heavier they are overall and hp loss due to the mass being farther away from the center.

THen again, if you get tired of swapping brakes I will gladly take them off your hands

My next mods will be NAV and differentials.

WindyCityS4 · 12-29-2005, 06:18 AM

FixedWing · 12-29-2005, 06:21 AM

As you say, it is cheap and relatively easy to do. And it does improve the bias situation a little.

If I have to I will go the RS4 rear brake route. More work because I need to find a set and that isn't so easy from North America. But I think ultimately worth the effort.

Still, it would be nice to be able to have the bias adjustable (preferably from the driver's seat) without changing the rear brakes and without the additional unsprung weight of all of these brake solutions.

But one question in the back of my mind is at what point the stock rear brakes will not be sufficient to keep up with a big brake kit on the front of the car. So far, I've not heard anyone complaining of fade on the rear brakes.

Stephen

12-29-2005, 05:55 AM	#1
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	Any thoughts on how brake bias can be adjusted on the S4 ??? The brake bias on the S4 is heavily biased to the front of the car. When we add big front brakes, we only make the situation worse. Normal practice is to increase the size and/or advantage of the rear brakes (S8 rear rotors or RS4 rear calliper & rotors). I would like to avoid changing the rear brakes if I can because I will continue to use 16 inch wheels in the winter. That means I will need to swap front callipers seasonally. I'd like to avoid also having to swap rear callipers if I can (the RS4 brakes will only fit under 18 inch wheels). So does anyone have any ideas on how the brake bias can be adjusted other than by mechanically changing the brakes? Stephen __________________ ================================================== ======================

12-29-2005, 06:00 AM	#2
WindyCityS4 AudiWorld Super User Account #: 52314 Join Date: Mar 2003 Posts: 7,544	Actually, almost every BBK kit moves bias toward the rear. I would bet that my S8 rears will... fit under 16's. There is a lot of clearance back there. __________________ In a world of constant change, it is the learners that shall inherit the future. For the learned soon find themselves capable of living in a world that no longer exists. Autobahn Country Club (North, South, combined), Blackhawk Farms, Gingerman, Grattan, Mid-Ohio, Putnam Park, Road America, Sears Point, Thunderhill and "The Ring"

12-29-2005, 06:02 AM	#3
Hal_TT::CBP Senior Member Account #: 3027 Join Date: Mar 2000 Posts: 9,679	Actually some of the BBKs move the bias rearward somewhat. Stoptech 332s for example, and these fit under the 17" Avus wheels. There are others I think(4 piston kits mostly) that do the same... you'll have to look at wheel clearances though, don't recall. __________________ Hal. Whoops... I wanna ride... APR Stg3 (and then some) Sold.

12-29-2005, 06:03 AM	#4
WindyCityS4 AudiWorld Super User Account #: 52314 Join Date: Mar 2003 Posts: 7,544	My 6 pot Alcons fit under stockers...and my 17" BBS RC's. __________________ In a world of constant change, it is the learners that shall inherit the future. For the learned soon find themselves capable of living in a world that no longer exists. Autobahn Country Club (North, South, combined), Blackhawk Farms, Gingerman, Grattan, Mid-Ohio, Putnam Park, Road America, Sears Point, Thunderhill and "The Ring"

12-29-2005, 06:08 AM	#5
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	I don't think the S8 route changes the bias enough... Really needs the RS4 rear brakes to do that. And this is likely to be the route I will end up taking. Stephen __________________ ================================================== ======================

12-29-2005, 06:09 AM	#6
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	Only with the smaller rotor size. __________________ ================================================== ======================

12-29-2005, 06:15 AM	#7
WindyCityS4 AudiWorld Super User Account #: 52314 Join Date: Mar 2003 Posts: 7,544	By math, the S8 have 10% more torque than stock rears. Bias ~70/30 (stock is ~72/28). Not much diff I agree with you. But since I needed rotors for the rears anyway, it eneded up being a $150 mod. I don't recommend it to anyone that wants "kit fitment". It is not a direct bolt on. The tweaking is very easy and fast, but still needs the use of washers to space out the carrier. __________________ In a world of constant change, it is the learners that shall inherit the future. For the learned soon find themselves capable of living in a world that no longer exists. Autobahn Country Club (North, South, combined), Blackhawk Farms, Gingerman, Grattan, Mid-Ohio, Putnam Park, Road America, Sears Point, Thunderhill and "The Ring"

12-29-2005, 06:17 AM	#8
davenew AudiWorld Super User Account #: 70028 Join Date: Feb 2004 Posts: 7,828	that's why I would get the smaller rotors I'm sure the smallest alcon kit brakes and dissipates heat better than stock brakes. I don't think the slight leverage advantage of the bigger rotors is worth the hassle of wheel fitment. Not to mention, the larger the rotors, the heavier they are overall and hp loss due to the mass being farther away from the center. THen again, if you get tired of swapping brakes I will gladly take them off your hands My next mods will be NAV and differentials. __________________ '00 S4 EPL Stg 3 (March'04-May'08) '08 BMW 135i Dinan Stg 2 (May'08-Present) '00 S4 Imola widebody AWE Stg 3 (Bought Nov'08. AWE stg 3 kit is sold.. I'm switching over to ASP GT soon)

12-29-2005, 06:18 AM	#9
WindyCityS4 AudiWorld Super User Account #: 52314 Join Date: Mar 2003 Posts: 7,544	Still bigger than stock. 8-) __________________ In a world of constant change, it is the learners that shall inherit the future. For the learned soon find themselves capable of living in a world that no longer exists. Autobahn Country Club (North, South, combined), Blackhawk Farms, Gingerman, Grattan, Mid-Ohio, Putnam Park, Road America, Sears Point, Thunderhill and "The Ring"

12-29-2005, 06:21 AM	#10
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	I agree that the S8 route makes sense as compared to stock brakes... As you say, it is cheap and relatively easy to do. And it does improve the bias situation a little. If I have to I will go the RS4 rear brake route. More work because I need to find a set and that isn't so easy from North America. But I think ultimately worth the effort. Still, it would be nice to be able to have the bias adjustable (preferably from the driver's seat) without changing the rear brakes and without the additional unsprung weight of all of these brake solutions. But one question in the back of my mind is at what point the stock rear brakes will not be sufficient to keep up with a big brake kit on the front of the car. So far, I've not heard anyone complaining of fade on the rear brakes. Stephen __________________ ================================================== ======================

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