Slotted rotor question

[Roadracer350]

Ok I may get flamed for this but here is my question.. 2 piece slotted rotors are around 300-400 each. Stock GT500 rotors are 50-80 each. Slotted 1 piece rotors are 100-125 each. My question is why can't I purchase stock GT500 rotors and slot them myself? I have access to a Bridgport with a DRO and I could put a big bolt circle pattern in and use like a .250 - .375 end mill and go 1/3 the thickness into the face and mill them out. At least in theory. Isn't this what the factory does to the slotted you can buy? We used to drill and champfer extra holes in stock bike rotors to aid in braking and cooling so same principal. Again in theory.. Any thoughts...

 

[dontlifttoshift]

Use a ball end mill. You will only do it once, machining rotors like that sucks and you will kill the tooling.

I didn't think modern pads had issues with outgassing that prompted the need for slots and holes.

 

[Roadracer350]

The bikes were mostly ductile iron and with carbide end mills and zero deg countersinks they were not to bad but that was bike rotors not car but in theory it should be the same. So your saying use a ball mill?

 

[dontlifttoshift]

Yeah, I would use a ball mill. You don't want any square corners, even in the bottom of your slot, so the ball mill keeps it all round.

Still don't think its worth the effort.

 

[Whiskey11]

I think I would be very cautious about creating stress risers in using any milling on a blank rotor. I think you'd be better off running the blanks then doing anything to your rotors.

 

[Sky Render]

Brake pads no longer use Asbestos. There is no outgassing.

Furthermore, your brake rotor is a heat sink. Why would you want to remove material from it?

 

[ddd4114]

What's the intended use?

If you have aggressive race pads, slots can provide a means for the brake dust to escape and not get trapped between the pads and the friction surfaces. When I used blank rotors, I would find lots of scoring on the friction surfaces and material buildup around the pads. Now that I'm using slotted rotors, I don't really have those problems, but I do find some pad material deposits around the edges of the slots. On the other hand, if you're using street pads, the slots have no real benefit and will only increase wear and noise. As you've noticed, they will also lighten your wallet.

Personally, I would never machine slots in blank rotors for the reasons mentioned above. My main concern is that they were never designed to have slots, so who knows what that kind of change will do for stress distribution and fatigue. I also wouldn't drive on a machined rotor unless all of the edges have been significantly smoothed (definitely use a ball end mill), and it has been annealed to remove any stresses created from milling. At that point, you might as well just buy a new blank rotor.

 

[SGTguy]

I don't see a problem slotting your stock rotors. I drilled and slotted a set of rotors for a friend and he had no problem with them, He even had then resurfaced with no problem. Most of the lower priced rotors are stock parts then they machine the slots or drill/slot them. On the rotors there is a number castes in them, that's the minimum they it can be resurfaced, don't cut your slots to deep.

 

[Roadracer350]

Yea I think I will just bite the bullet and buy the Gyrodisc 2 piece and be done with it

 

[Roadracer350]

Ok couldn't afford the rotors I wanted right now so I purchased 1 piece Stop Tec slotted rotors and I'm a little miffed about this... These rotors look like stock GT500 rotors with .125" slotts that has been machined with a ball end mill... This would have been easy to do and cheaper... Live and learn I guess. Unless your buying 2 piece save yourself some time and slot them yourself..

 

[dontlifttoshift]

piece save yourself some money and slot them yourself..

Fixed it for you.

 

[Roadracer350]

LOL!! Yea your fix is what I should have said!

 

[Lgs SGT]

.... Stock GT500 rotors are 50-80 each. ..

If you don't mind sharing where do you find stock GT500 rotors for that price?

 

[SuperchargedStang]

Fixed it for you.

But time=money, so both of you said the same thing? lol

 

[RocketcarX]

Ok couldn't afford the rotors I wanted right now so I purchased 1 piece Stop Tec slotted rotors and I'm a little miffed about this... These rotors look like stock GT500 rotors with .125" slotts that has been machined with a ball end mill... This would have been easy to do and cheaper... Live and learn I guess. Unless your buying 2 piece save yourself some time and slot them yourself..

Why would you expect something different from a stock style slotted rotor. I'm curious as to what you were expecting.

 

[Vorshlag-Fair]

Everyone knows about modern brake pads no longer de-gassing and the added stress risers from the holes, so drilled rotors are now out of fashion. Slotted rotors can serve one small function in racing: to scrape away a tiny amount of pad material, to keep the pad surface "fresh". If your pads are prone to glazing this might be advantageous, and many 2-piece racing rotors are slotted.

http://youtu.be/_L_ev1iuGzg

That video has a lot of marketing fluff, and honestly... I think drilled and slotted rotors is still mostly about image. There is no cost effective 2-piece 14" Mustang rotor (they cost 5-10 times what a 1-piece rotor does) and the slotting/drilling is mostly unnecessary, in my humble opinion. So on our Mustangs with 14" front rotors we use Centric premium rotors.

Best bang for the buck. They have a coated center so they don't rust the first time it rains and they last a good long time.

But if you like bling, go for it. We just put slotted and drilled rotors (and upsized both the front and rears) on our shop truck. Because I'm secretly a pimp.

At least the rotor manufacturers are now using a generous chamfer on the holes and ball nose endmills for the slots. So it isn't as rotor cracking as it could be...

 

[Roadracer350]

The stock GT500s I found were from Orylies. The ones I got were just slotted. The way I was thinking was from the bikes. We don't use slotted but we do use drilled. Well the cars don't use drilled because of the cracking but I was figuring with the slotted it may help keep the glazing down and even tho the pads don't out gas the slots will help clean the pads and maybe help a little with cooling. I may be totally wrong but it was just a theory. I found these slotted rotors for 89 each. I Wasent expecting somthing earth shattering I was just expecting maybe a Stoptech rotor not a Centric rotor with slotts machined in them and a Stoptech sticker in the box. Oh well you live and learn.

 

[ArizonaGT]

Another vote here for the Centric Premium rotors (blanks). Cheap and effective. No unsprung weight savings, but I'm not sure that's worth the money yet vs. buying tires and getting more seat time.

 

[NoTicket]

Drilled is common on bikes because they don't need as strong rotors (stopping a total of about 580-600lbs) and they weight savings is pretty much the only thing that they care about.

 

[csamsh]

Stoptech and centric...they are the same company now, just fyi