need your rotors drilled? get it done cheap.

Rocan said:
oxford; thats completely wrong. hole diameter should be equal to or less then rotor thickness, otherwise you DECREASE surface area.
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I disagree, to end up with the same amount of surface area after you drill the hole as before you started you will drill a hole with a diameter twice the thickness of the rotor. This is using 3.14 as pi.

Example: 6mm thick rotor. You drill a 12mm hole which will have a surface area(A=pi times radius squared) of 113.04 multiply this times 2 for both sides of the rotor. You end up with 226.08 of surface that is now missing. You know have surface area on the inside of the hole of where it was just drilled which is 6mm wide by 37.68mm long(12mm times pi= circumfrence). The area of this(length times width) comes out to 226.08, the same number that you lost by drilling the hole.

Maybe you have a different way of figuring out surface area, I would like to hear it.
 
Sorry to interject into your discussion, but could one of you explain to me what benefit is gained by maintaining the surface area on a drilled rotor? Is it for heat dissipation? I was always told drilling rotors was to help scavenge the gasses that build up between the pads and the rotor under braking.
 
This isn't gonna turn into an argument is it? This was just an ad, never meant to stir anything up.
 
Depends what carrier you and I use, but we can go flat rate shipping with usps, should only be like 10-14$, but maybe cheaper since we may be able to fit them in a really slim box
 
A lot can be learned from this kind dialog. I don't think its stiring things up at all. And USPS flat rate padded envelope inside another one should be just fine to ship and I think they're under $10.

"Burnin' oil and smellin' royal!"
 
Im totally with ya on that, I was just afraid it would start getting rude.

Thanks for the shipping info. Much appreciated, Ive been sick with strepped throat so hadn't had time to check it out at the post office.
 
Oh ok.. o was just wondering if anyone had shipped a rotor before and which carrier is best/cheapest. I guess that flat rate envelope is cheapest.

Sent from my Droid using Tapatalk
 
tsbigdog said:
Sorry to interject into your discussion, but could one of you explain to me what benefit is gained by maintaining the surface area on a drilled rotor? Is it for heat dissipation? I was always told drilling rotors was to help scavenge the gasses that build up between the pads and the rotor under braking.
Click to expand...

There are two important "surface area" considerations.

First, there is the total surface area of the rotor. The greater the ratio of the surface area to the total volume of the rotor, the faster the rotor will cool, generally speaking. As oxford stated earlier, drilling does not greatly affect this total surface area. It will reduce it by a small amount, however, if the holes are properly camferred.

Second, there is the surface area of the rotor that actually contacts the pads. This area is of great importance (bigger is better!) and drilling will always reduce the size of the contact area. Any large contact area between the pads and rotors is important for being able to turn friction into heat (e.g. stopping you effectively) and also for pulling heat away from the smaller pads and into the rotor itself, thereby reducing outgassing from the pads and, in extreme circumstances, boiling of the brake fluid.

The trick with drilling is to find that happy medium where the outgassing from the pads doesn't get stuck between the pads and rotors (known as brake fade) while keeping enough surface area to allow decent grip and heat transfer.

Too much drilling and you get poor stopping power and/or overheated rotors (which can then lead to warped rotors, boiled brake fluid, excessive brake pad wear, etc). Not enough drilling and you get brake fade as things heat up.

One semi-related note: The hotter something is, relative to the other objects in which it is in contact, the faster the two object transfer heat. For instance, a rotor at 800°F will cool to 700°F faster than a rotor at 700°F will cool to 600°F. Because of this, it is usually better to err on the side of more drilling rather than less. Just don't go overboard.
 
Thanks for the lesson on brakes. Learned some new things and knew some others.
 
Sonreir,


Thanks for that info. Have you come across any documentation or done any comparisons to see how much of a difference drilling the rotors can make? I think that would be a great selling point for this service. It would also satisfy my insatiable curiosity. At least for a little while. ;D
 
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