Rear Rotors hotter than the front rotors
09-20-2012, 01:41 PM
#3
My first ricer
iTrader: (4)
I've never once thought about it, but theoretically they should be since they're smaller, less metal to disipate heat. They also have less braking force than the fronts, so that last thing I said could be absolute crap. If they're not glowing I wouldn't sweat it.
09-20-2012, 01:50 PM
#5
Moderator
iTrader: (7)
one time I did a quick spirited drive down a mountain road. by the time I got to the bottom my rear brake pads started smoking. Front brembos were working perfectly, no smoking, minimal fading. Brembos are great 
stock rear brakes, not so much. and yes these are oem brake pads and rotors all around.
stock rear brakes, not so much. and yes these are oem brake pads and rotors all around.
09-20-2012, 04:12 PM
#6
Suzuka Master
if the rear is hotter than the front then seem you have a stuck piston.
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09-20-2012, 04:50 PM
#9
Instructor
Thread Starter
Haha, I just determined by hand.
The rear two calipers are new.
I did some highway driving, stopped. The front two rotors are cool, rear twos are a little bit hot, not too hot though when I touch them
.
Not a big deal though; I feel that the rear one might takes long to cool down because it's small
The rear two calipers are new.
I did some highway driving, stopped. The front two rotors are cool, rear twos are a little bit hot, not too hot though when I touch them
.Not a big deal though; I feel that the rear one might takes long to cool down because it's small
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LaCostaRacer (09-20-2012)
09-20-2012, 06:03 PM
#11
Suzuka Master
09-20-2012, 09:50 PM
#12
Drifting
You go down Pikes Peak and the Rangers shoot your brakes with an infrared thermometer. If your brakes are too hot they won't let you proceed farther down the hill. The TL has smaller rear brakes and if you're going down hill it wouldn't surprise me if the rears are used more. There's less mass to absorb the heat so they might run hotter- plus are the rears not ventilated like the fronts?
09-21-2012, 02:39 PM
#13
I think your rear caliper is stuck. The front all hotter then the rear. Because the front is heavier then the rear. That it why the front rotor are bigger then the rear.
09-21-2012, 07:50 PM
#14
Team Owner
The fronts do more of the braking under hard braking but under easy braking with EBD it's close to 50-50. Cars feel more stable under braking when the rears are doing their fair share or even the majority of the braking. Fronts are 11.8" (auto) 12.2" (Brembo) and vented. Double the mass and quadruple the surface area of the rears to get rid of heat. Couple that with a bicycle-like 10.1" solid rotor (my mountain bike has 8" rotors lol) in the rear and near even brake force distribution and you can see how the rears can run hotter than the front under normal conditions.
Before I did the 13" 4 pot Stoptech upgrade, I shot brake temps every day after I got done with a trip on the stock brakes to get an idea of temps. I did it so that I would have an idea of how the aftermarket brakes affected brake bias. My rears almost always ran hotter unless I had just done a few spirited stops.
Off topic but with the Rotoras, rear temps went down, fronts stayed about the same. Bad.
With the Stoptechs, rear temps went back to stock levels, fronts are amazingly cool. Good.
Before I did the 13" 4 pot Stoptech upgrade, I shot brake temps every day after I got done with a trip on the stock brakes to get an idea of temps. I did it so that I would have an idea of how the aftermarket brakes affected brake bias. My rears almost always ran hotter unless I had just done a few spirited stops.
Off topic but with the Rotoras, rear temps went down, fronts stayed about the same. Bad.
With the Stoptechs, rear temps went back to stock levels, fronts are amazingly cool. Good.
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justnspace (09-21-2012)
09-22-2012, 11:53 PM
#15
I Just got the brakemotive pads and rotors and they get super hot,. Are drilled slotted rotors supposed to get that hot. I just had them for a day so I don't know if this is normal, also I can smell that dust coming out the pads. it's been only a day but I don't know if this is normal.
10-11-2012, 07:33 PM
#16
Team Owner
I had my temp gun with me today and thought about this thread so I shot some temps after an easy drive home. Ambient is about 75 degrees I think, got to look that up in a few.
Front rotors were 128 degrees.
Rear rotors were 158 degrees.
Front calipers were 90 degrees.
Rear "calipers" were 123 degrees.
The temps would be closer to equal if I did not have a BBK but still, it goes to show that there is probably no front bias during easy braking. Rear temps should remain the same with stock brakes, fronts will go up a little.
Right before I park the car I do a 60-5mph stop, drive about 50' and shut it down so it's definitely not a best case scenario. Rotor temps are all over the place depending on where you shoot. IR guns have a hard time with shiny things. Sometimes the friction surface will show 80 degrees but point it at the darker, less polished hat and it's 400 degrees. I always take the hottest temperature on each rotor.
Front rotors were 128 degrees.
Rear rotors were 158 degrees.
Front calipers were 90 degrees.
Rear "calipers" were 123 degrees.
The temps would be closer to equal if I did not have a BBK but still, it goes to show that there is probably no front bias during easy braking. Rear temps should remain the same with stock brakes, fronts will go up a little.
Right before I park the car I do a 60-5mph stop, drive about 50' and shut it down so it's definitely not a best case scenario. Rotor temps are all over the place depending on where you shoot. IR guns have a hard time with shiny things. Sometimes the friction surface will show 80 degrees but point it at the darker, less polished hat and it's 400 degrees. I always take the hottest temperature on each rotor.
10-11-2012, 08:29 PM
#17
03-25-2013, 08:16 AM
#19
Team Owner
It's not a problem, it's just the way they work.
03-25-2013, 09:53 AM
#20
Cruisin'
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wth. Apparently some of y'all have never worked on brakes if you cant seem to figure out how he found out. Unfortunately OP didnt check them the correct way (with a infrared thermo). As for the OP, if its a huge difference in temps, could be a bad proportioning valve, the caliper cup is sticking, or the e-brake is set too tight.
03-25-2013, 02:11 PM
#21
Suzuka Master
iTrader: (2)
Just did new Centric rotors and RB ET-500 pads last week and the driver side rear was almost down to metal on both pads. One of the rubber boots on one of the caliper slides was torn and both slides on that caliper were stuck. That caliper was also leaking a little, so I picked up a rebuilt NAPA caliper and new slides and boots for the passenger side since those boots weren't fitting right. Keep in mind these calipers were just replaced in 2010. I'm sure it didn't help that I never flush fluid, but I did it this past November and plan to stay on top of it from now on. People in the northern states should also seriously consider inspecting the boots and cleaning and greasing the slides on an annual basis.
03-25-2013, 04:14 PM
#23
Drifting
i remember reading somewhere that the accord wears down the rear brakes faster than the fronts. i think it was one of the widespread car magazines who was doing a 1-year test on a 2010 accord. since the two are practically the same car, that would explain a lot.
03-25-2013, 04:17 PM
#24
Team Owner
Or said another way, the proportioning valve does nothing during normal easy driving.
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