Z06Tracker

After just one event on a set of new front OEM C5 calipers, I have pad taper worse than I had on the old calipers. The inside pads (the inside pad on both the left and right side of car) are tapered badly from top to bottom, with the bottoms much thinner than the tops.

If caliper spread is the cause of tapering, why do I have so much tapering on new calipers?

Also, I usually run Carbotech XP12's on the front, but this event I ran Carbotech RB2's. Could the significant difference in taper be caused by the difference in pads?

Thanks in advance.....

Sidney004

Just to clarify, is the pad taper radial; where the pad wear is greatest at the outer diameter of the rotor and decreases toward the inner diameter or is it a longitudinal pad wear where the pad wears greater at the leading edge of the brake pad(where the rotor enters the caliper?)

Z06Tracker

The later...I was calling the "bottom" the end of the pad on the ground side.

redtopz

I had the same problem with my stock front calipers. I switched to the wilwood SL6 calipers from LG that run the thick 20 mm pads and allow you to run stock 17" wheels. The thicker pads make a huge difference in pad and rotor life and I'm not getting the taper problem anymore. I just ran 6 track days (1 corvette challenge, 4 time trials and races, and a test day) on a set of CL RC6 pads and they still are as thick as a set of new OEM pads. I did not have to replace rotors (except for one cracked rear napa rotor) or even bleed my brakes once over those 6 events. Plus the wilwood size pads are much cheaper than OEM size pads.

Sidney004

For starters, I think you can rule out caliper spread because what you are describing is longitudinal pad taper. The "bottom" of the C5 pad is the leading edge, you should expect higher temperatures and wear at the leading edge of the pad.
This is from the Stoptech website:

"The trailing area (portion) of the pad, to some extent "floats" on the entrapped gasses and particulate matter generated from the leading portion of the pad. The leading portion of the pad will always be hotter than the trailing portion and so will correspondingly, wear faster - resulting in a pad that is tapered when viewed from the edge. This phenomenon is termed "longitudinal taper".

The differential in heat generated across the pad surface, leading to trailing, is characteristic regardless of caliper and pad design. This is why all racing calipers and most high performance street calipers have differential piston bores. Most high performance pads also feature a tapered leading edge."

http://www.stoptech.com/tech_info/wp...lections.shtml

brkntrxn

Morris,

I wish I had looked at the pads when I was at your house the other day. Agreeing with the others, this does not sound like caliper spread like you were getting before. I am willing to bet the taper you have is due to those endurance track pads. Running *****-out on cold endurance pads in Time Trials is probably what did it.

Have you called Danny, Chris or Mike yet?


-Kevin

Bill Dearborn

Is the outside pad tapered just the exact opposite with the top of the pad being thinnest? That is what I typically saw when I was running my C5s with stock calipers. First saw it on my 97 when I took it to an HPDE with a little over 2K miles on the car. This kind of taper doesn't have anything to do with caliper spread and more to do with caliper twisting on the guide pins as the brakes are being applied. You also get a very long pedal as the pads taper more and more during a session.

Here is a picture of the pads from the 97 that was taken about 10 years ago. It shows the tapering of both pads one caliper:


Bill

Z06Tracker

I will look closer, but I did not notice the outside pad having anywhere near the same taper as the inside pad.

RX-Ben

Thanks for this post. I experienced this taper when trying out a new top secret high mu compound during my last session at NJMP. FWIW, I did a lap within .3 of my best time with little or no friction material remaining on the inner LH side pad. The pads on the RH side had ~2-3mm left (hardest braking was for a RH turn).

JVetthead

With stock calipers on track you are going to get taper, period. I still run them and to get the most life from pads I swap them side to side so the taper evens out. I run xp-12.
i.e. The left outer becomes the right inner.
The left inner becomes the right outer etc.

travisnd

I run XP12s and flip them side to side on the same caliper. Not as effective at what JVetthead describes but easier to do. Flipping them allows you to switch which end of the pad is the leading edge. I typically do the flip after each track day.

The inside pad is the one the pistons are actually pushing against, the outer is compressed by the action of the slide rail. Not sure if this may have anything to do with the wear being seen on the two inboard pads. Also, do you have brake cooling ducts with spindle ducts yet?

sperkins

Carbotech pads taper so badly because they're designed to be soft. The wear rate on their 12/10 combo is just rediculous. They always state how easy their pads are on rotors, but how much sense does that make when a set of front pads is $220 and a rotor is $35?

After years of sending them my money every other month, they've lost my business because they have repeatedly refused to support the grassroots racer with any type of contingency. As racers we must support those who support us and unfortunately, Carbotech chooses not to.

BTW- an across the board forum discount is not the same as a racers contingency.

RX-Ben

I have a brake cooling setup. The harder CL RC6E pads did not have this much taper, though I was busy with other stuff during the weekend and never swapped these (note to self about prioritizing pad swaps).

Jim 47

I've done this pad swap for years. The above method is absolutely the most effective way to do it. Just jack up the front wheels, remove the wheels, and in about 10 minutes the swap is comleted.

Jim

drivinhard

ya'll are all using your brakes way too much

froggy47

What additional advantage is there by swapping side to side? Assuming brake function is good.

Sidney004

Not to be dense but is that changing the leading edge of the friction material? When you swap the inner and outer on the same caliper, the leading edge is reversed but is that taking place with this method?

RX-Ben

As you can see from my pics, the dominant issue with this type of taper is not leading edge wear. The L outer to R inner swap mentioned above deals with taper that resulted in my wear pattern.

Why haven't my stock calipers deformed yet? Not enough braking force w/275 R6s?

brkntrxn

Let's try this again, looks like my first post went into lala-land.


I agree!


In all seriousness, I think pad taper issues can also be traced back to braking method. After studying TraqMate data from our Time Trials runs at VIR in March, it is blatenly evident that Morris (Z06Tracker) brakes much differently than me. He is gets on the brakes much later and much harder than I do. Sometimes by as much as 200' later. We both come off the brakes at about the same time, but he compresses his brake zone much better than me. However, I do not see the pad taper issues that he sees. My pads wear much more evenly and I think it is due to my braking method of braking earlier and longer. I think I might go through more rotors than Morris, but my pads definitly wear more evenly. I think his "hard" hit on the brakes is taking material off the leading edges. Whereas I lean into the brakes and gradually get to threshold.

(If I could merge his braking ability with my accelerating ability, we might actually be able to hang onto Mark/Scott/Travis' bumper).


-Kevin

travisnd

With Corvettes I brake easy for a split second to get the pad/rotor in contact with each other, then go 100% full brake.

I don't just jamb on them 100% out of the blue..... I used to do that because I was taught to threshold brake in that manner at the racing schools I'd been to. I used to crack rotors every weekend if not every day.

Once I modified my style a little the brakes behaved much better. I don't drag the brakes or brake long IMO.