BartSimpson

I am getting some 20" wheels and I am worried that my stock brakes on my 06' GT will not be enough to stop the car as quickly as with the stock 17" wheels. I am thinking about getting a big brake kit with either 4 piston calipers or maybe even 6 piston calipers. Would this help to stop the car faster with the 20's? I also know that the stock brake system (rotors and pads)will wear out faster with 20's, will a big brake kit last longer?

ChiDiddy

bigger brakes do not mean better stopping power. all you need are some decent brake pads and you're good to go. Hawk HPS and Axxis Ultimate (do they make them for stangs?) are my top two for daily driving. Axxis Ultimates dust up a LOT, but have really good braking. (ceramic type). Hawk HPS dust less, and brake a bit less, but still ton better than stock.

drbobvs

Try Akebono pads too, no dust and dead quiet.

83gtragtop

Bigger calipers mean more clamp force, thus better braking. Bigger rotors means better cooling and thus better braking. Better Pads means more friction and thus better braking.

Brian

UrS4

Wow!

Someone with the wherewithall to ask about brakes when upgrading to 20" rims. Kudos to you BartSimpson [sm=smiley20.gif]

A big brake kit will help you stop faster as long as it is a kit that is engineered to work with the S197. Slapping on a huge kit because you have the clearance may tax your master cylinder too much.

Make sure you upgrade the rears too. I would suggest at the least you get SS lines, better fluid, better pads like Hawk or CentriQuiet or EBC. Slotted rotors over drilled but there is a debate as to whether stock sized rotors that are drilled or slotted actually stop faster than non slotted drilled rotors.

A cheap alternative would be to upgrade the front to GT500 calipers and rotors and do the SS lines, fluid and better pads front and rear.

F1Fan

GEEZUS!

To the peoplethatbelieve larger brake rotors and caliperswith more pistons will make you car stop faster or in fewer feet wheredid you go to school? If you can hit the brake pedal and lock up the brakesactivatingtheABS on your S197 Mustang your car is stopping as fast as it is going to stop no matter what size rotors with whatever drill or slot pattern, with 2, 4 or 6 pistons onone or two piece rotors and 17"-22"wheels and tires period. This is because brakes don't slow the car down, TIRES do!

HTH!

UrS4

I understand the tire part but do you agree that switching pads from stock to Hawk or EBC causes you to stop in a shorter distance due to more friction generated by the better pads? With that said wouldn't using bigger pads (greater swept area) create more friction and provided the tires were soft enough to maintain traction slow the car down faster and thus in a shorter distance?

When I had my Audi, I was running a summer tire with stock calipers and rotors but better pads and the car stopped sooner. And when I went to a larger Porsche caliper and rotor and larger pad the car stopped significantly faster.

Can you please explain as I would like to learn more about brake upgrades as I thought the more friction you generate the quicker you can stop.

F1Fan

Hi UrS4,

The limiting factor in how short a given car can stop is the friction the TIRES can genrate not the brake system. If you kept the same suspension and tires ona car and the brakes were working properly before installing larger calipers with 4, 6 or 8 pistons and larger 14" or 15"2-piece rotors the car will stop in approximatelythe same distance. The reason is the tires cannot generate any more gripthen they could before you installed those monster sized brakes. Also consider the fact that with more rotating mass you not only have more mass to stop you have more mass to accellerate so whilea little bitbigger may be an advantage in terms ofbrakingtoo much bigger brake rotors may actually hurtthe car's accelleration.

Knowing this can you see that adding more swept area and larger pads cannot improve stopping distances?What adding more pad area does is potentially increase pad life. Longer pad life is a nice thing to have but alarger pad area means you need to better support the brake pads to prevent poor pad wear patterns due to the various forces working on the calipers, pads, rotors, hubs etc. This is where multiple pistons with different sizebores comes into play. By varying the piston bores carefullyyou can for a given pad shape, caliper stiffness and mounting style reduce irregular pad wear to a minmumimproving pad life. More pistons doesnothing to improve single stop braking distances just as larger higher friction coefficent pads and larger rotors do nothing to reduce single stop braking distances.

Once the car has stopped two, three, four or more times the brakes will start to heat up and need to cool down or the stopping distances will start to go up with repeated use and inadequate time for the brake system to shed the heat of conversion. This is thereal advantage to larger diameterhigher mass rotors with better ventilated brake rotors, the ability of the larger brake system to absorb and shedheat. If your caris street drivenand only occasionally sees a road course a much more effectivebrake upgrade than a big brake kit would be to optimize your stock brake system by improving the brake pads using pad materials with a higher friction coefficent, reduced brake line compliance, resistance to fluid failure (boiling),and massively improved cooling of the rotors. In return for performing these upgradeson your stock brake system your car will stop just as well as the car with giant brake rotors all aroundAND your car will accellerate faster thanhe other car. Your brake padsand rotors will lastmuch longer and your car willbe able to make repeatedstops from high speeds with much less brake fade AND they will recover much faster! The guy who spent his money ona big brake kit will be able to stop a few more times beforehis brakes start to overheat butoncea big brake kit has overheatedall the extra mass of the larger rotors of abig brake system will be working against him as they willtake longer to cool down before his brakes are back into the normal heat range. Without effective brake coolingbig brakes are no better stopping when overheated than your stock brakes. As you can see cooling the brakes isthe key to effective long lasting brakes.

I used to design and build Porsche and VW race suspension parts for various teams and private parties. Trust me your Audi and Porsche did not stop any faster because of thelarger brakes or higher friction pads you installed. If you had your cars insturmented you would have seen the same peak and averaged stopping forces before and after the brake upgrades IF the stock brakes were working right to begin with and you did not change the tires or suspension settings. What you probably felt was the higher friction and lighter pedal pressure needed to get into the ABS which you may have interpreted to mean that the car was stopping faster. This is a common misinterpretation of pedal travel, pressure and stopping feel.

Does this help answer your questions?

Cheers!

ChiDiddy

F1Fan speaks the truth. On a street level, pads are MORE than enough to stop your car better than stock. (given proper tires as well). a BBK is NOT the answer. Brake fade is the enemy of effective braking, u want NO brake fade. a simple pad and fluid change can already do wonders. good pads and Motul RBF600 or ATE Blue DOT4 brake fluid.(or any fluid that has a high wet boiling point than stock fluid)

sd07gt

Hi,

What can you recomend as far as brake pads that dont squeal, but are much improved over stock ? most people use Hawk HPS ? I heard that the HPS + pads work great but squeal allot .

Any info would help !