Brake Rotor Advice

[Jason_25]

Guys I need to decide on what brake rotors to buy. Here are my requirements.

1.Maximum braking performance
2.NO WARPING!!!
3.They have to be able to hold up off-road to mud and stuff.

Thanks in advance.

 

[yob_yeknom]

I'd like to hear opinions too. My fronts are under the minimum thickness, so I've gotta get new ones soon. I'd like ART's, but can't justify that kind of money on brake rotors. Any input on those brute stops?

 

[mattadams]

does Stillen make anything for the Explorers? I can't remember and I couldn't find anything on their website. I'm looking at getting those for my F-150 as soon as they come out. The ART's are pretty good from what I've heard but I couldn't do them for my F-150 (they have them available for the front but not the rear and I want to do both)

 

[BRacing]

Brembo makes replacements called "blanks" - they don't have any slotting, drilling, etc. They're just a replacement, but are much cheaper and better quality than the ford units.

Hope this helps.

 

[Raceit]

I've been needing front rotors for my 944. I've ran across some web sites. I'll post one of them. To find more you may want to search for them.
There are a few companies that will "freeze" rotors. They freeze them about 300 below F. I won't try to explain why this helps. But a large group of people swear by them.
They say that it virtually eliminates warping and extends the life of the rotor at least 200%. Plus it helps extend the life of the pads as well. But if warping is a main concern then I'd ask around about it.
But to get preformance I think you'd have to upgrade to bigger brakes which would cost some serious dough. Cross drilled (or even better "cast" cross drilled) rotors only help to disipate heat. So if you have problems now with brake fade then those or even slotted rotors may help. But those two will usually start to crack faster because of the holes and slots in each rotor. Plus the slotted will wear your pads down quicker.
So maybe just some frozen rotors and some high quality brake pads will give you the performance and strength that you are looking for.

And that's just my two cents.

http://www.frozenrotors.com

 

[Jason94sport]

I have ART fronts & been VERY happy. To meet your requirments, you will have to spend some money. You can still get the discount from Dean at ART. 200% better then stock!

 

[DocVijay]

I've got the ART rotors.

I've had them for about 10k miles now. I got both front and rear, plus their higher performance pads. So far I'm very happy with them. They definitely stop much better, and feel much better than stock. Plus, if the cryo treatment does make them last three times as long, then great. Here are some pics of them.

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Like Jason said, mention that you are fromthis board and you'll get some $$$ off. Not bad. Get them, I think they're worth it.

 

[Maniak]

We run the ART rotors as well. It did eliminate the warping problems we had, and the pads are lasting longer (that may be from using "Performance Friction" pads.

We did also notice the front brakes work much better now. Especially when they get wet.. the old brakes didn't stop.. the new ones stop much better. We could tell the difference between the stock and ART, but it isn't as much as a difference as you would see with outright bigger brakes.

Here is an article on the ART rotors.. (install/review)

http://mark.legendz.com/explorer/art/art1.htm

 

[Robert]

Performance Products has a set of slotted rotors. They look like the ART rotors, maybe they are? I don't know how they hold up but may give them a try in about 8 months. I will need rotors then. How much do the ART rotors cost? The Performance Product ones run around $100 a set (front or rear).

 

[Alec]

I looked at the ART site and they run $300 a set with pads, with some discount for members.

 

[soupbone]

another alternative would be brembo. they make explorer OE sport kits now. slotted disc and pads for $269.

 

[BRacing]

Remember, drilled rotors do not improve performance, and their only real advantage is a slightly lighter unsprung weight. Many sanctioning bodies and race tracks actually prohibit the use drilled rotors because of the increased chance of them cracking.

The advantage of slotted rotors is neglegable, and slotting itself does not prevent warping or improve cooling. The overall design of the rotor is what prevents warping and improves cooling.

This comes from years of racing experience.

Hope this helps.

-Brad

 

[DocVijay]

Don't mean to open a can of worms, but...

I'm going to have to disagree about drilled/ slotted rotors not helping. They can in fact help braking performance in many instances. The primary purpose of drilled/slotted rotors is to help dissipate gas. This gas is from dust, water, anything on the pad or rotor. With all the friction, this stuff burns up and forms gasses. This gas prevents the pad from fully contacting the rotor. The slots/holes let this gas escape and thus the pad now has much more surface contact. Perfect example is rain. The rotors get wet. When you put on the brakes, the water turns to vapor. holes help this water vapor escape, instead of lubricating the pad/rotor contact. I consider this a great advantage, much better than just lower weight. If weight is a concern, there are now cool ceramic rotors available. Another benefit is that the slots/holes help to keep the pad surface fresh. Everyone knows you have to break in you new pads or they'll glaze, and be less effective. The slots help to "shave" the face of the pad and make it more effective. There are downsides though. Drilled rotors are more prone to cracking, but drilling them properly can help to minimize this. As for warping, it does help a little, as the holes do help cooling somewhat. Brad is right about this, the venting and overall design of the rotor is much more important to cooling. Plus, they usually cost a lot more than the regular slabs.

 

[Raceit]

I would have to agree with you DocVijay.

I've read that drilled can reduce rotor temps by as much as 250 degrees F and slotted can reduce as much as 100 degrees F. Drilling 20 1/4 inch holes will not save that much weight. The whole point was for cooling and there for reducing brake fade.
The downside as we all know are the drilled will have a tendency to crack quicker as well as the slotted to a certain degree.
But with race teams replacing items on a more frequent basis that sometimes isn't even an issue.

 

[BRacing]

I'm probably out numbered here, but ignorace is bliss.

Drilled rotors are BAD. Here's why...
The holes make the rotor more prone to cracking due to uneven surface cooling. The lesser material in a drilled rotor does allow it to cool faster, but at a more uneven rate. The lesser material of the rotor also HEATS UP quicker, causing heat problems with the brake fluid and the pads glazing. Only then do the holes help eliminate glazing, but only because they caused it in the first place. Most of the cooling process is from the veins (fins) inbetween the two sides of the front rotors. The holes only prohibit this process.

You must be asking, "Then if they suck so bad, why do they exist?" Here's why...
Back in the day brake pads had asbestos, as well as other compounds, that would release gasses when heated under severe usage (racing, towing, etc). The holes allowed a space for the gasses to go in hopes of increasing braking performance. HOWEVER, brake pads have advanced so much in the past couple decades that they no longer 'out-gas' under sever usage.

They STILL exist mostly because people don't understand that the 'out-gassing' of brake pads is a thing of the past. Plus, most people buying them just want to look cool.

So very few racers actually buy them. Those that do buy them is to save the unsprung weight at each wheel. These race cars are so light and performance oriented that this actually matters on their million dollar machines.

"But what about water/mud/etc?" Water shouldn't be an issue. There is ALWAYS some pad drag/contact on the rotor creating heat in the rotor - enough to dissapate water faster than it can become a factor. Because the pads are always touching the rotor, the rotor gets wiped clean by the leading edge of the pad before the braking surface of the pad makes contact with the rotor. Holes and slots only prevent this process.

"But they keep the pads 'fresh'!" Um, no. Unless you run REALLY ****ty brake pads under severe conditions, or you don't know how to properly "bed" in the pads with the rotor, you should NEVER have a glazing problem.

"I still believe that cross-drilled/slotted rotors are better than blanks..." Fine. But also think about auto manufacturers R&D and production. If they were better, why don't we see them on more performance cars? It wouldn't be that much more expensive on a $50k car to come equipped with drilled/slotted rotors, right? Why doesn't it come with the "Tornado" in the intake too???

I've worked with the R&D at Wilwood, and they know that drilled/slotted rotors don't work. They sell them because there is a demand in the market for them. I've raced for almost 10 years (I'm only 23) and have never seen drilled/slotted rotors work better than blanks.

On the other hand, under EXTREME usage, cryo-treating the rotos does help prevent cracking. But you gotta have some tiny brakes on a big-ass race car running an enduro race to be able to tell.

I'm getting tired of trying to explain this over and over again. If you would like more information, see the Grassroots Racing Magazine issue about a year ago. There's a HUGE article in there talking about the brakes.

I'm writing about this because we are a community; a family. I don't want you to spend more for an inferior product or something that may fail. I do this because i care. I'm not trying to hurt your feelings, but just inform you of what is the truth, and to dispell the old-wives tales of yester-year.

-Brad

 

[Jason_25]

Brad,

Thanks for dispelling the "hype" and getting down to the facts. In that case, what rotors do you recommend for my application?

 

[BRacing]

Brembo

Brembo "blanks".

it's an OEM replacement for rotors. They cost less than original FoMoCo and are less likely to warp.
-Brad

 

[BRacing]

BTW - i think they can be ordered through Summit Racing or NOPI.

About $40 a pair.

If not, let me know.
-Brad

 

[FrankRizzo]

You don't mention if you have 2 or 4 WD.

Newer 4WD X's have two piece front rotors that adapt to the late model Cobra brakes fairly easy...EE stocks the kit now.

 

[DocVijay]

Ferrari 360, Ferarri 550, Porsche 911 (Carerra/ 911/ GT2), Mercedes 500SL, Aston Martin Vanquish, Lamborghini Diablo, Lamborghini Murcielago.

All these high performance cars come from the factory with drilled and/or slotted rotors. There are more.

On tarmac, WRC rally cars use huge 15" rotors that are slotted.

If you take your Vette to John Lingenfelter or your Viper to John Hennesy, both of them slap on new rotors. Lingenfelter uses slotted and Hennesy uses drilled.

Here are some quotes from a few companies' web sites:

Mazdatrix: "Brake pads fade when the temperature of the material allows gases to "boil" out and create a layer separating the pad from the brake rotor. The holes in these rotors allow the layer to escape thereby keeping the pad in contact with the rotor. The rotor will also run cooler, which helps keep the pads cooler while also reducing the risk of fluid boiling. Note: Pads WILL still fade, and fluid WILL boil if the brakes are used beyond their SAFE capacity. Additionally, drilled rotors tend to crack around the holes due to heat expansion and contraction. Therefore there is no warranty on these parts, and the customer assumes all responsibility for their safe use."

Stillen: Drilled - "Computer-aided design, (CAD) is employed to determine the optimum pattern for any size Rotor. This pattern is critical, for it must correctly sweep the Brake Pad to increase its initial bite and allow for out-gassing while also cleaning the entire Brake Pad surface. The sweep will eliminate hot spots and maximize the Brake Pad friction to the rotor. The added air-surface, created by cross-drilling, will increase the rotors ability to dissipate heat and cool more effectively."
Slotted - "Both Slotted and Cross Drilled Rotors offer advantages over stock rotors. Cross drilled offer a better initial bite and braking, slotted are more resistant to high thermal loading. Like the cross drilled rotors above, CAD is used for optimizing the slot pattern."

Power Stop: "Question- Why should I use cross drilled rotors?
Answer- The primary reason is that they run cooler, approximately 200-250 degrees cooler when used with high quality pads. This reduces the chances of warping, which has become a major problem in recent years, particularly on late model U.S. made vehicles. Additionally you will experience improved wet weather braking. If you are experiencing pulsation on the brake pedal, your rotors are warped. It may be possible to turn them, but they will then be thinner and unable to dissipate heat as quickly, and will soon warp again."

Rod Millen Motorsports: "Computer-aided design, (CAD) is employed to determine the optimum pattern for any size rotor. This pattern is critical, for it must correctly sweep the Brake Pad to increase its initial bite and allow for out-gassing while also cleaning the entire Brake Pad surface. The sweep will eliminate hot spots and maximize the Brake Pad friction to the rotor. The added air-surface, created by cross-drilling, will increase the rotors ability to dissipate heat and cool more effectively."

Brembo:What are the advantages of drilled and slotted discs?
The main advantages of drilled and slotted discs are the same: increased brake "bite", and a continuous refreshing of the brake pad surface. Drilled discs have the additional advantage of being lighter and running cooler. However, there are certain pad materials that should not be used with a drilled disc."

There are more of those, but my post is way too long already. I do agree that cross drilled, and to a lesser degree slotted, rotors are more succeptible to cracking. However this doesn't happen very often. Even a drilled rotor has to be severely stressed to crack. Racing does this. But they also change rotors frequently, so even racers that use them don't have this happen too often. I have my own race experience, both sanctioned and, well, let's say "unsanctioned." Yes, I have seen cracked rotors, but it wasn't too common.