Joshboody

Posted in big brake thread, but topics get lost in there

My rear pads wear more than the fronts.
2001 C5 coupe
Front WW narrow SL6 and stock rear with ST43s
All nannies always off

01 fluid distribution is LR/RR and RF/LR, so 50/50 split “unless” wheel speed warrants DRP. So you’d wear more in the rear unless DRP was active correct?

I’m a fairly light braker and rarely feel ABS. So think I’m not braking hard enough to wear fronts like most. Agreed? Or could this be hardware... I've checking everything a lot and seems fine. Unless its the BPMV.

Charley Hoyt

Usually that is from abs “helping” more than you realize.

Mick14

Yes....you are either letting the "nannies" do too much or you have something wrong with your braking system.

Hi Volts Z06

I had the same problem after I put on my ST-60 BBK. I used up a set of rears in a day at Watkins Glen in a fairly long day of race practice. After chasing my tail with "solutions" such as different compounds and changing to the C6 Z51 rotors, I broke down and bought a matching ST-40 kit. Problem solved. C5 brakes are woefully inadequate in race conditions especially when you've upgraded the fronts.

SocalC5Z

Is the car balanced under braking? Does the back end want to come around trail braking into a turn? On the 2001's the brake bias is managed by the ABS unit, so it's not a simple think to change it. Most people with C5's wear the fronts significantly faster than the rears, even with BBK's

On my 2002 C5Z, I run a WW Aero6 with 14.25" rotors with the stock rears and ST43's and the front still wear out quicker than the rears, at least 2:1.

Joshboody

I always have all nannies off

You are the first person that has stated similar situation to me... everyone else wears significantly more front than rear.

Braking seems balanced to me, but I’m still a newbie with about 30 track days. My braking Gs are rarely over 0.9 and peak for only a short time during the braking zone. Pedal gets longer over the day, so I don't have much confidence to really stand on them yet.

I've rotated the backend entering corners and its controllable, but its not a regular occurrence yet. I have not noticed that I need more front bias.

I go over and have changed hardware (for no obvious reason) without a change in the overall discrepancy between front/rear. However, greatest individual pad wear will change though from side to side inside rear pad.

Example of my driving on a short track with 200tw 275s. This day rear pad wear was about 1.5x of the front.

ErnieN85

I'll second that, I also have worn rear pads after going to a larger front brake setup. It stoped when I added the matching Wilwood rear setup
Give Tod at Tce performance a call

maj75

Essex Big brakes on the front of my C5 and no unusual rear brake pad wear.

0Todd TCE

The total cubic inches of friction material between those two pads is huge, sure that's not the reason?

SocalC5Z

I seem to recall there is a difference in how the rear brake bias is adjusted on the late C5's vs the earlier cars. My 2002 with a front BBk wears the rears at half the rate or less compared to the fronts and there IS a HUGE mismatch in pad and rotor size.

Once again... I remember reading on CF something about this. I have never found anything on the brake hard lines on my 2002 that would be a brake bias valve. It has to be in the ABS unit. I believe the earlier cars had a stand alone bias valve, but I don't recall all the details.

Joshboody

Yes, this is why my theory is that I'm not braking hard enough to yield more front wear.

My understanding for 01s fwd, the 2 zones are RF/LR and LF/RR instead of front to back. Equal line pressure is applied to each zone UNTIL there's a difference in wheel speeds then electronic ABS is applied for DRP (dynamic rear proportioning). So due to the pad surface area if DRP is NOT applied I'd think rears would wear more than fronts. Brake harder for more pressure to be applied to the front.

So maybe I'll grow bigger ***** before next event to check it.

Bill Dearborn

The 01 through 04 cars have something called Rear Stability Control:

When the vehicle performs a high speed turn or curve, the EBCM will enter rear stability control mode. The vehicle speed is greater than 48 km/h (30 mph) and the vehicle lateral acceleration is greater than 0.6 g. The vehicle will exit rear stability control when the vehicle speed is less than 40 km/h (25 mph) or the vehicle lateral acceleration is less than 0.4 g.

During a rear stability control event, the EBCM performs a pressure increase on the outside rear brake and a pressure hold on the inside rear brake. The driver may hear the pump motor run and may feel a vibration in the brake pedal.

This description is a separate paragraph below the Stability Control Description in the 01 FSM. I don't know for sure whether it can be turned off when you turn off Active Handling. It might explain the difference in pad wear.

The 01 and up cars also have dynamic rear proportioning which will feed more pressure to the rear brakes if the rear wheels aren't on the verge of locking up.

I used to run the LG G Stop kit on my 03Z. That kit used the wide SL6 caliper and permitted the use of the 7420 pad Vs the 7416 pad so I got up to 10 track days on a set of front pads as long as I countered taper that built up in them by changing positions in the calipers. The rear pads would last about 6 or 7 days. Running stock front and rear calipers the rear pads would wear at about half the rate of the fronts when using Wilwood H pads which is what I continued to use with the G stop kit. So rear pad wear didn't really increase but the front pads wore much longer due to a lot more pad material being available.

Bill

Joshboody

An update, same track braking harder and I wore more front pads. Closer to 1.1g compared to 0.9 peaks from previous event. Basically same time on track with below pad wear. So I think my question was answered.

Light braking (total mm wear)
Front 1.9mm / Rear 2.9mm

Heavier braking
Front 3.9mm / rear 2.6mm