misterp Posted February 14, 2011 Report Share Posted February 14, 2011 So I was talking with Sam Strano today; he's a world-champion autocross racer, suspension guru/expert, and a genuinely great guy. So while I had him on the phone, I asked him about the rotors on my SSS - I have Baer 6S calipers on the front with 15" rotors, and Baer Alumasport calipers on the rear with 14" rotors; I have about 60K-miles on them, and the fronts are showing a bit of wear but the alarming thing is that the rear rotor wear is so bad that the slotting is completely gone! The pads have totally chewed the rotors to nothing. I asked Sam if he had heard of this before on the GM trucks, and he shared with me that the culprit is that the brake system not only has computer-controlled antilock, but also computer-controlled brake bias. What this means is that unlike vehicles in the past where the proportioning of front/rear brake pressure was 'fixed' by design in the plumbing, the late-model GM trucks are constantly varying the front-to-rear applied brake pressure in real-time, all the time; this happens during normal driving as well, whether the ABS is activated or not the brake bias is constantly 'moving'. I did not realize this feature existed in the ABS box. Sam agreed that in his observation, because of the electronic brake bias and programming in the GM trucks the rear rotors take it in the shorts and wear out in 1/2 the time as the fronts. So, after a long story - these GMT-800 & later trucks *eat* rear rotors, and basically there is nothing we can do about it, and we have to live with it! Mr. P. Quote Link to comment Share on other sites More sharing options...
70chevy03ss Posted February 14, 2011 Report Share Posted February 14, 2011 I have the stock setup on my truck. I can't tell you how many times i had to replace my calipers and rotors! Thank god my fater works for NAPA. I havn't had to touch them in a while thank god.. It sucks but what are you going to do!! Quote Link to comment Share on other sites More sharing options...
SSplaytoy Posted February 14, 2011 Report Share Posted February 14, 2011 For every front set I do, I do the rear twice. I always wondered why, and weight distribution didn't make sense, so now I know. Thanks for the info Steve. Quote Link to comment Share on other sites More sharing options...
arturomoreno Posted February 14, 2011 Report Share Posted February 14, 2011 that sucks... Quote Link to comment Share on other sites More sharing options...
04CHASE Posted February 14, 2011 Report Share Posted February 14, 2011 (edited) cool guy i had his suspension setup in my 02 ss camaro with koni adjustable 4/4 shocks , that car was so awesome i really miss it. (with the rims and suspesion it handled great) and ran mid 12's n/a on skreet tires. i have seen stock disc gmt-800 truck go 100k+ on stock brakes . i have noticed that my rears wore out first when running the alumasport all around for a couple years. but i had new rotors a few times from the crack issues the old baers rotors had. the valve under the master cylinder appears to be a proportioning valve , wonder why they didnt just do away with it . Edited February 15, 2011 by 04CHASE (see edit history) Quote Link to comment Share on other sites More sharing options...
ss wrecker Posted February 15, 2011 Report Share Posted February 15, 2011 I've seen this with my wrecker it eats rear pads like no other Quote Link to comment Share on other sites More sharing options...
SuperStock Posted February 15, 2011 Report Share Posted February 15, 2011 I did the rear at 75k. I had the factory rotors turned down and put new pads on. At like 105K the piston pushed out to far out of the caliber and the brakes took a dump one me. Quote Link to comment Share on other sites More sharing options...
Warden Posted April 8, 2011 Report Share Posted April 8, 2011 So does this mean that the rear brakes are grabbing off and on while we are driving along and not touching the brake pedal? So I was talking with Sam Strano today; he's a world-champion autocross racer, suspension guru/expert, and a genuinely great guy. So while I had him on the phone, I asked him about the rotors on my SSS - I have Baer 6S calipers on the front with 15" rotors, and Baer Alumasport calipers on the rear with 14" rotors; I have about 60K-miles on them, and the fronts are showing a bit of wear but the alarming thing is that the rear rotor wear is so bad that the slotting is completely gone! The pads have totally chewed the rotors to nothing. I asked Sam if he had heard of this before on the GM trucks, and he shared with me that the culprit is that the brake system not only has computer-controlled antilock, but also computer-controlled brake bias. What this means is that unlike vehicles in the past where the proportioning of front/rear brake pressure was 'fixed' by design in the plumbing, the late-model GM trucks are constantly varying the front-to-rear applied brake pressure in real-time, all the time; this happens during normal driving as well, whether the ABS is activated or not the brake bias is constantly 'moving'. I did not realize this feature existed in the ABS box. Sam agreed that in his observation, because of the electronic brake bias and programming in the GM trucks the rear rotors take it in the shorts and wear out in 1/2 the time as the fronts. So, after a long story - these GMT-800 & later trucks *eat* rear rotors, and basically there is nothing we can do about it, and we have to live with it! Mr. P. Quote Link to comment Share on other sites More sharing options...
misterp Posted April 8, 2011 Author Report Share Posted April 8, 2011 (edited) So does this mean that the rear brakes are grabbing off and on while we are driving along and not touching the brake pedal? Yes - kinda: in theory when the truck is totally loaded with weight you want more braking at the rear, and when you are running with an empty bed you want very little braking in the rear, so the computer is moving that brake bias between front/rear as it sees fit - in addition, on AWD trucks the ABS may engage the rear brakes slightly upon launch to force more torque to the front axle. Edited April 8, 2011 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
Warden Posted April 8, 2011 Report Share Posted April 8, 2011 Well that blows.It can't be good for mileage.I'm surprized no one has tried to defeat this function.At least have an on and off switch to use only when it's critical. Quote Link to comment Share on other sites More sharing options...
misterp Posted April 8, 2011 Author Report Share Posted April 8, 2011 Well what really needs to be done is to mount a pressure sending unit at the rear brake T-fitting and log some driving; what I was told is 'qualified hearsay' but it is a theory that fits the circumstances... Quote Link to comment Share on other sites More sharing options...
Warden Posted April 9, 2011 Report Share Posted April 9, 2011 I know it would be too complicated.How about a controllable transfer case out of a 4 X 4? Quote Link to comment Share on other sites More sharing options...
kris4647 Posted October 29, 2014 Report Share Posted October 29, 2014 This is still almost sticky worthy information, just happened on my '03. Quote Link to comment Share on other sites More sharing options...
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