Brakemotive drilled and slotted rotors. (pics)

I have brakemmotives on my truck,03 envoy with the pads that came with it. Ive had no issues but its also just my weekend cruiser so my experience may be invalid to most. I will say that they are starting to look crappy compared to when they were first put on but it happens.
 
Not a fan of "intuition" arguments. They usually cite a couple of scientific principles and then claim that their much larger and more complex overall point, therefore, is also a scientific fact. That's not science. Science is coming up with a hypothesis, such as "it will take longer to come to a complete stop from 60 miles an hour using a cross drilled and slotted rotor vs. a solid blank rotor on an otherwise identical trailblazer," and then actually going out and TESTING that hypothesis.

Einstein had to wait many years after devising his theory of general relativity before it was recognized by the scientific community because they had to actually test his theory first. Even after "proving" general relativity, it is still regarded as a theory, because ultimately there are no facts in science, just hypotheses that have yet to be disproven! (In fact, I believe certain elements of his theory have since been disproven?)

There are actually many claims involved in this argument so it would require many tests. There's braking distance, propensity for cracking, brake fade performance due to heat dissipation or lack thereof, etc.

Even if you did run proper tests showing poorer performance in some category, now you have to provide a specific alternative that is economically a better choice. If your alternative lasts 25 percent longer but costs twice as much, then the brake motives are still a better buy. As it is, brake motive rotors are some of the cheapest deals out there for us that have a really good reputation. The cross drilling was just coincidental in my own purchasing decision.

I'm not saying those against these types of rotors are wrong. I'm saying go out and prove your theory.
 
xtitan1 said:
Not a fan of "intuition" arguments. They usually cite a couple of scientific principles and then claim that their much larger and more complex overall point, therefore, is also a scientific fact. That's not science. Science is coming up with a hypothesis, such as "it will take longer to come to a complete stop from 60 miles an hour using a cross drilled and slotted rotor vs. a solid blank rotor on an otherwise identical trailblazer," and then actually going out and TESTING that hypothesis.
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Nah, science is settled and whatever the loudest voice says it is. :biggrin: Dissenting arguments are persecuted by the church of science.

xtitan1 said:
Einstein had to wait many years after devising his theory of general relativity before it was recognized by the scientific community because they had to actually test his theory first. Even after "proving" general relativity, it is still regarded as a theory, because ultimately there are no facts in science, just hypotheses that have yet to be disproven! (In fact, I believe certain elements of his theory have since been disproven?)
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:hijack: Thread hijack. Some of his theory is observable via testing. Then came quantum physics flying in the face of it. Now science is working out the unifying theory to make sense of why the universe is so nuts and two theories at odds with each other seem to both be correct and wrong?

When the answer all along is 42. :crazy:
 
its the inverted pyramid of 42 or 17 actually.
 
mikekey said:
:iagree:

The argument against sounds about as solid as the guys who used to argue that drum brakes were just as good as disc brakes. No, they don't put them on F1 cars. They do put them on Corvettes, Porsches, AMG Mercedes, M series BMW's, Ferraris, Lambo's etc from the factory. These engineers didn't do it just becuase it's "cool" looking.

Yes, increased surface area and more pistons do improve efficiency. Heat reduction from cross drilled can actually save brake fade.

If you're a guy with larger tires try slamming on your brakes 10 times in a row from 60mph and heat those things up and tell me there is no such thing as brake fade.

x2 for the EXT brake upgrade with the brake motive, only thing I wish I could do is find a 4 piston caliper that will fit my 17inch rims.

Mine:
new_caliper.jpg
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What exactly is needed for the EXT brake upgrade?
 
He posted a nice write up on the conversion today...

rotors, caliper brackets are big things.
 
I don't really think there is an argument against drilled rotors. I think the discussion is whether they are purely for looks or if there is some kind of benefit.

One cannot compare apples to oranges, and thus one cannot compare their old worn-out pads and rotors to new ones, drilled or otherwise. It appears Brakemotive makes quality rotors, and that in itself would be an improvement, drilled or not.

If done properly and made by a quality manufacturer, I can't really see the downside to drilled rotors. After all, we do a LOT of stuff to our trucks strictly for the looks.

But there is no scientific argument that they brake better. It is just not physically possible.

The holes cannot cool the rotor more because lateral holes move zero air through them when the rotor is turning. Those of us who fly are very familiar with the term "boundary layer" and the fact that air cannot suddenly turn 90 degrees sideways and enter or exit a lateral hole in a brake rotor while it is spinning. There is no airflow through those holes when the rotor is turning at speed at all, simply because the innermost microscopic layer of air next to the rotor surface cannot suddenly break away from that surface to flow 90 degrees.

Modern pad materials do not need to be "de-gassed" or whatever that holdover from brake shoes from the 1950s was.

So if there is no air flow through those holes, we are left with simply the amount of metal that must be used to absorb the heat. Does a greater surface area result in a cool and possibly better rotor?

Again, no. It doesn't make scientific sense. Look at the barrel of a modern rifle. Rifles that are made to shoot to the same point of impact shot-after-shot, in spite of the potential for greater heat build-up in the barrel seriously impacting the accuracy of the shot, are made with greater mass in the barrel, NOT greater surface area. This is what they call a "bull barrel" and it is the solely the diameter of the barrel that is larger. Serious police and military sniper rifles NEVER use holes, flutes or other devices to increase the surface area; they use greater mass to absorb the heat. To maintain accuracy shot after shot, the metal must absorb the heat, not try to dissipate it as soon as possible ... which, in the case of both rifle barrels and brake rotors, could never be done in time to affect performance anyway.

So, if you remove any mass whatsoever, you lessen the ability to absorb the heat and you lessen the performance of the rotors.

Now, going back to the argument that they are for looks and they do little harm, one could argue that the holes remove so little mass in comparison to the overall weight that it really doesn't decrease performance to any appreciable amount. I agree with this.

So, scientifically, given the same quality of rotor and the same size, there is no way drilled rotors can increase braking performance over regular rotors. If anything, scientifically they decrease performance. But again that would be such a miniscule amount that is one chooses to add them for the looks and one finds a quality manufacturer, go for it. There is no possible cooling effect from the holes, but they don't really decrease the mass too much if designed properly.

The ones that worry me are the ones where too many holes are drilled everywhere, strictly for the looks and with no regard for the internal cooling fins (that actually DO cool rotors significantly.)

So, in my opinion, formed from what I consider scientific evidence as a former airplane pilot, performance vehicle tester and professional shooter, the holes give no advantages; quality rotors from quality manufacturers do give an advantage, holes or no holes.
 
Last I checked some gun barrels are vented to keep them from overheating and distorting, like some heavy machine gun barrels.

fuel to the fire :tongue:
 
If D/S rotors were not a functional benefit, then why does EVERY motocross guy, hardcore bicyclists, and others swear that D/S rotors are the way to go?


Heat displacement. Talk to an autocrosser? Many gripe overhow fast their non D/S rotors burn up and fade on track day.
 
Playsinsnow said:
If D/S rotors were not a functional benefit, then why does EVERY motocross guy, hardcore bicyclists, and others swear that D/S rotors are the way to go?
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LOL! Last time I checked, motocrossers and hardcore cyclists are also not immune to putting on stuff just for the looks.

Sparky said:
Last I checked some gun barrels are vented to keep them from overheating and distorting, like some heavy machine gun barrels.

fuel to the fire :tongue:
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Fuel to the fire! LOL!

Machine gun barrels are solid steel. What you are seeing is the cooling shroud over top of the barrel. It uses convective movement of air through the openings to help cool the barrel. Most modern machine guns don't use them anymore because they rely on the mass of a heavy barrel, plus the ability to quickly swap out a hot barrel for another.
 
Chickenhawk said:
LOL! Last time I checked, motocrossers and hardcore cyclists are also not immune to putting on stuff just for the looks.


Fuel to the fire! LOL!

Machine gun barrels are solid steel. What you are seeing is the cooling shroud over top of the barrel. It uses convective movement of air through the openings to help cool the barrel. Most modern machine guns don't use them anymore because they rely on the mass of a heavy barrel, plus the ability to quickly swap out a hot barrel for another.
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Couldn't convection work, in principle, with drilled rotors too? I mean the metal IS heating up, which would mean the air (especially if at a standstill thanks to the boundary layer explained above) within the drilled pores would also heat up, and heated air wants to expand and would go out of the hole, but to keep atmospheric pressure more air would want to go in...

Also, the idea behind the vanes between the two halves of the rotor is to operate like a squirrel-cage motor to induce more airflow. Doesn't do a whole lot of good when coming to a complete stop, but I guess it helps. Wouldn't some of the airflow, being drawn from the middle generally, want to escape out of the holes? And how do basic squirrel-cages even work when the vanes are 90 degrees relative to the circular center? (I'm not getting into curved vanes here, but plenty of stuff uses regular straight vanes.)
 
Might as well throw my purely anecdotal response into the mix...I live in a relatively hilly portion of my province and went through 2 sets of front pads and rotors in 2 years due to heat warping, after the second time I decided to try something different and went with the d/s rotors and ceramic pad from Brakemotive and 3 years later they're still in there and adequately scrubbing off speed. In a brief testament to how that company treated me as a customer, when I placed the aforementioned order they ended up sending me a set for the rears. An email followed and they sent me the correct set for the front and let me keep the rears for free.
 
Snailblazin';200959 said:
Might as well throw my purely anecdotal response into the mix...I live in a relatively hilly portion of my province and went through 2 sets of front pads and rotors in 2 years due to heat warping, after the second time I decided to try something different and went with the d/s rotors and ceramic pad from Brakemotive and 3 years later they're still in there and adequately scrubbing off speed. In a brief testament to how that company treated me as a customer, when I placed the aforementioned order they ended up sending me a set for the rears. An email followed and they sent me the correct set for the front and let me keep the rears for free.
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Not a bad deal, pretty much half-off brakes. That's a good customer service story if I've ever heard one, normally a decent story would be them picking up the tab on the return shipping and sending you a proper set without having the old ones in their hands yet, but that's actually quite nice.

I would imagine your improvement involves both the pads and rotors. The pads are a different material, I'm not sure if ceramic pads are prone, or can even, contribute to cementite deposits on the rotor.

As for the rotor, I would imagine the slots help with dust removal on the pad-side during operation which may help to improve performance, but this part is entirely personal speculation.
 
IllogicTC said:
As for the rotor, I would imagine the slots help with dust removal on the pad-side during operation which may help to improve performance, but this part is entirely personal speculation.
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Basically, cross drilled and slotted will help dissipate heat and gasses that build up from the friction of the pad contacting the rotor during braking which inturn will help with stopping distances. This definitely helps with braking on hills or if you are lifted with bigger wheels and tires.

When I was in high school, I installed D/S rotors on my Honda. I assumed they would produce more brake dust over stock, but it was quite the opposite. They also help with braking as my wheels were upgraded from 14" to 17". I cannot speak to how they perform on our TBs though as I have yet to do this mod, but looks like I will be adding it to my summer mods :yes:
 
dmanns67 said:
Basically, cross drilled and slotted will help dissipate heat and gasses that build up from the friction of the pad contacting the rotor during braking which inturn will help with stopping distances. This definitely helps with braking on hills or if you are lifted with bigger wheels and tires.

When I was in high school, I installed D/S rotors on my Honda. I assumed they would produce more brake dust over stock, but it was quite the opposite. They also help with braking as my wheels were upgraded from 14" to 17". I cannot speak to how they perform on our TBs though as I have yet to do this mod, but looks like I will be adding it to my summer mods :yes:
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Yeah, I remember my Honda. First car I ever owned, fresh out of high school and without a dad to show me the way of the wrench, it was where I picked up the basics of auto repair, and jury-rigging. As in, the plastic vacuum advance on the distributor busted on the single loop holding it in place, so I wedged a pop can between it and a coolant line to hold it in place.

Those were the days, man.
 
bullguy said:
REMEMBER...... Your car will only stop as fast as your tires will allow. All the braking in the world won’t work if your tires are bald and on ice!!
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Unless you have Blizzaks. :biggrin:
 
Nothing like increasing the rotational mass and having tiny rotors that can't handle it. :no:

Oh well. We all know that cross-drilled/slotted rotors are for show and only stupid people like myself install them. We know this, because all the smart people have informed us of our stupidity in this thread, multiple times. I feel grateful personally. :wink:
 
mikekey said:
Nothing like increasing the rotational mass and having tiny rotors that can't handle it. :no:

Oh well. We all know that cross-drilled/slotted rotors are for show and only stupid people like myself install them. We know this, because all the smart people have informed us of our stupidity in this thread, multiple times. I feel grateful personally. :wink:
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I know my truck stopped like sh!t with the AT2's on it. Its a bit better with the Pirelli's, but I am thinking of going treadwright for my spare set of wheels. I want to do a few places later this year and the Pirellis are not going to cut it. So I will them mounted as a spare set.
 
blazinlow89 said:
I know my truck stopped like sh!t with the AT2's on it. Its a bit better with the Pirelli's, but I am thinking of going treadwright for my spare set of wheels. I want to do a few places later this year and the Pirellis are not going to cut it. So I will them mounted as a spare set.
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Yeah! It's true, tread plays just as much a part of stopping physics as weight of rim, vehicle and other things. :thumbsup:
 
mikekey said:
Oh well. We all know that cross-drilled/slotted rotors are for show and only stupid people like myself install them. We know this, because all the smart people have informed us of our stupidity in this thread, multiple times. I feel grateful personally. :wink:
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Most likely coming from people who have never tried them or heard someone else saying the same thing. I have used D/S and know they make a difference. Opinions are like excuses and excuses are like a$$holes. Everyone has one and they all smell like $hit.
 
dmanns67 said:
Most likely coming from people who have never tried them or heard someone else saying the same thing. I have used D/S and know they make a difference. Opinions are like excuses and excuses are like a$$holes. Everyone has one and they all smell like $hit.
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Usually the people who spout from the mouth only regurgitate what they read or hear. It's sad, but that how it works.

I used to see it all the time when I raced my Accord, V8 guys with the no replacement for displacement, blah, blah, blah. Funny watching them get beat up on by my buddies all motor Civic.
 
blazinlow89 said:
Usually the people who spout from the mouth only regurgitate what they read or hear. It's sad, but that how it works.

I used to see it all the time when I raced my Accord, V8 guys with the no replacement for displacement, blah, blah, blah. Funny watching them get beat up on by my buddies all motor Civic.
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Well we all know ricers live in fantasy land, so :raspberry:
 
mikekey said:
Well we all know ricers live in fantasy land, so :raspberry:
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Whoa, I love a v8 as much as I like a 4 banger. I have seen some awesome cars from both ends of the spectrum. However like most things I have the friend who praised Honda's (not sure why) and those who would look at everything that isn't a V8 is useless. I have had many phases with vehicles, thankfully when I did toy with 4 bangers I never riced them. I always liked the sleeper look.
 
No, rice is an early 90s Civic with a racing stripe run along the length of the car along the top... done in duct tape. The dull silver did nothing for the beige/tan factory color the Civic still had. I knew the kid, he was kinda goofy but I wasn't expecting to see that sitting by his house.
 
Rice is anything with tires stretched to fit too wide of wheel.
 
Rice is installing a spoiler large enough to provide tons of downforce just from the weight of the thing. Any aerodynamic-related forces are a bonus.
 
tokahao said:
Just got mine installed yesterday and did the break-in. I took a couple pics afterwards and noticed that the front rotor surface is wider than the pads. Has anyone else noticed this? I have a LWB... perhaps I was sent the wrong set of pads or maybe the wrong rotor! :eek:

You can't tell from the pics, but there is a 4th hole in the drilled sequence. The 1st picture shows that hole right below the pad.

If this is normal for BrakeMotive, can anyone recommend a bigger brake kit or pads to take advantage of the surface area of the rotor?
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SBUBandit said:
I'm pretty sure this is the case with every set of brakes I've ever seen on a GMT360, its just that you're looking closer now and noticing it
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I know this is an old thread, but I had the same question as tokahao after installing my Brakemotive set. I thought it was normal as the rotor/pad combo that I took off had that same untouched strip near the center. I checked other GMT 360/370's and found both conditions: strip near the center untouched (older units) and pad contacting rotor all the way to the edge ('08, low mileage, all original 360).

Original 360:



My truck:



I will be asking Brakemotive if there are other pads, but apparently they aren't the only ones selling the pads that are smaller. I'll grab pics of my old rotors when I get home as I have them in the scrap metal pile in my back shed.

I do know that I like the brake feel and power, so no complaints, but I feel like I'm getting gypped just a little bit! :hissyfit:
 
I've had 4 sets of Brakemotives on 4 vehicles for 5 or 6 years now, and I've decided I won't be using them on my cars anymore. I'm thinking my problem is perhaps the pads, because on my TB, I used Monroe Ceramic pads, because I found a great deal and already had them, and installed Brakemotive rotors. Those have been terrific for 40K-ish miles. On my cars I have installed the full sets with the pads, and they drone so loud stopping they drive me crazy. From 55-60 mph, they damn near scramble your brain with the drone and everything in the car buzzing. The ones on the TB are and always have been silent. They are due for me to pop them off in the next few months and flush the brake fluid and check things over in there, so I'll see then how even everything has worn.
 
My wife's car had some droning on stopping so I replaced the pads that came with the set with AC Delco ceramic pads. The sound was immediately gone. Now, a few thousand miles later, the drone/buzz is back. Not annoying yet and it isn't affecting stopping at all. Not sure what it is about the car ('04 Impala) that causes it do that. Like you, my TB is still quiet and stopping great with the pads that came with the set. I want to bleed my fluid as well, but the rear bleeders are both twisted off the calipers. I may pull them off and try to remove them and if I can't, I'll get some "new" calipers.
 
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