kristopher_d

I just changed my brake pads, ought to have done it sooner, but I didn't.

What I found was that I'd used more than 99% on the fronts and less than 40% on the rears. Which says to me the brake bias is awfully heavy to the front.

I'm very hard on the car. I like to play hard, and I play a lot. Is there any kind of adjustment that will move some of the braking power to rears? This would improve stability considerably as well as extending pad life.

I have springs sitting on my deck, and will be ordering shocks tomorrow, but, I still want the rear tires doing more work in the braking zone.

Is there an adjustment that may be wrong, or am I looking at some sort of custom replacement bias valve?

expo1

There is a reason front pads and rotors are larger than the rear. When you step on the brakes the weight of the car shifts towards the front. So Front brakes will always preform more work than the rears. So long as your car doesn't pull and stops like it should there is no reason for you to desire to change it. In fact it can be dangerous messing with them.

RoXanneBlack8

expo could not be MORE right. the brake wear is even more drastic on FWD cars. if u want as close to nuetral braking strength per axle, id say get a RR porsche.

to add insult to injury mazda uses Electronic Brakeforce Distribution on the rx8 and what that does is itll limit rear braking ability during certain braking times depending on cornering, angle, yaw, blah blah blah......which makes the rear brakes work even less.

sorry bud, ur stuck, front brakes wear faster.

if u want it the other way u can get a mazda3, those damn rear calipers, i swear, they must stick or something bc they go thru rear brakes twice b4 needin fronts even once......honestly

dannobre

iTrader: (3)

Front brakes should wear 2-3 to one with the rears......... What you see is very normal.

DarkBrew

No. Adding rear bias decreases the stability of the car. As stated before, the wear pattern is normal.

Marc_GS

It's true that the EBD will add forward brake bias to the fronts under certain conditions, but it will also do the opposite when conditions allow. Most of the time, and EBD equipped vehicle has MORE rearward brake bias than a non-EBD vehicle, simply because the designers can use the system to ensure that the rear brakes never lock before the fronts. Without EBD, you have to have a lot of front bias built-in to make sure that the rears don't lock up even under hard braking with lots of weight transfer towards the front.

I agree with everything else others have said, but would just add that even on a Porsche 911, with it's very rearward weight bias, the front brakes are still much bigger than the rears, and see more wear and heat.

kristopher_d

According to basic mechanics, tensile forces are dynamically stable by definition, compressive forces dynamically unstable. Rear brakes are acting in the tensile direction for a forward traveling vehicle.

The problem is, the front's are the only ones I ever convince to lock up (I could certainly stomp on the brakes to lock up the rears, but that's not what I'm referring to). I understand it's normal, I'm just looking for that extra braking power, and to establish a load angle for the weight transfer more in line with the vehicle's dynamics. I guess it's time to start doing some math.

Thanks for the input, my question is answered.

gregor

My Passat wears rear pads faster than fronts, and warps rotors in the rear. Quite a few family and less performance oriented cars will bias toward the rear in an effort to limit dive under moderate braking, then once that limit is exceeded bias shifts frontward.

Phantom Menace

Really? Hmph...HOW?

Cam

iTrader: (1)

kris,

Adding more rear braking would unstabalize the car.
Plus, since the RX-8 has ABS, there is no valve that could be replaced, all the "valves" are actually solenoids controlled by the ABS unit.

climacus

kristopher, you need to buy a book on applied vehicle dynamics before messing around with your suspension and brakes. I don't think you really understand how vehicle dynamics work in real life. Under no circumstances do you ever want to lock up your rear brakes. In a straight line, this causes wild fishtailing. In a corner, it'll literally spit you off the road. This is the #1 cause of race cars wrecking in a corner.

eforer

I can attest to that, all my race cars have and have had a bias bar. One always tries to get brave and dial in increasingly more rear bias to make the car turn in more and dial out some push. If you go too far it starts to get evil and over steer, should you lock up rears, congrats! Insta-Spin!

kristopher_d

Yes, I know. I've purchased and even READ several books on the subject. Thus my comment on doing the MATH. In fact, that's why I asked the question to begin with. Before assuming someone is an uneducated fool, it would be wise to read and comprehend their posts. the process I follow = Math -> controlled test -> math -> controlled test -> ...

dannobre

iTrader: (3)

With ABS the bias isnt as important.....you hammer on the brakes.....and the ones with the least grip trigger the ABS

mattvit

doesnt the car have a 48/52 front/rear weight distribution....claiming a 50/50 balance when braking???? shouldnt this reduce the brake wear on the front

praxis1301

if you're riding a bike and hit the brakes... which one will stop you quicker? the fronts. why? your weight is pretty even on a bike... when you are sitting still. however physics laws of motion come into play. when you are hitting the brakes you are slowing the wheels at that point, and causing a force to act on everything else. the braking causes you to lunge slightly forward(or flip over the front handlebars) because of this motion.

now for a car, the center of gravity is much lower so instead of having that lunge from the weight up high(like you on a bike) you simply have more weight that you have to slow. the weight of the car wants to continue in a forward(hopefully) motion so the front brakes will have the most to weight to stop. even if the rear brakes hit hard, the weight will still be in the forward direction, but you'll lose stability and control from the rear wheels being locked.