Drilled Brake Rotors

[brianinpa]

The recent discussion of rotor got me thinking. :help:

I have a few extra rotors laying around now and it is time to experiment... Are there any other benefits to having drilled brake rotors other than heat dissipation? Is just an ordinary hole needed or does it need to be counter-sunk? Is one pattern preferable over another? Inquiring minds want to know.

 

[slabghost]

Counter sunk ore chamfered holes further reduce the surface area for pads to grip but may increase pad life. Straight holes Will wear the pads faster. Pattern of holes needs to be even enough to retain disk balance but not so even to set up harmonic vibration. Holes will reduce weight and allow more pad grip along with provide better grip when wet.

 

[tuna boy]

Please report on how hard the the rotors are to drill and if you used high-speed steel or carbide drills. Not to state the obvious but you need a drill press and cutting oil or a water soluble oil would be better. Plain water would be OK too. Center punch each location and start with a 3/32 or 1/8" drill. If that goes well drill all the way through. Then attack the rotor with the 1/4" or what ever diameter you want to end with. I would not chamfer the holes. I want a sharp edge to help scrape the pads clean. If you can get through with the small drill first the bigger hole will much easier. Please let us know how you think the process goes.

 

[brianinpa]

I plan too. I was thinking 1/4" maximum: maybe even smaller. I guess I am lucky in that I have some wheels off of a 78, so I have three rotors that I don't need and can play with before I even begin to get to the rotors off of my 1100 parts bike.

 

[Ansimp]

opcorn: opcorn: opcorn: opcorn: opcorn:

 

[tuna boy]

If you can lay out the hole pattern in a sweeping curve your rotors would clean the entire pad face on every revolution. You could drill one rotor and clamp a drilled on an undrilled face to face. Use the first rotor to guide the drill for the second one. Put a 1/4" bolt in 2 spaced holes and put a nut on and torque. Nothing will move after that, drill away.

 

[brianinpa]

Time in front of the drill press is what I need now...

 

[joedrum]

a bunch id say brian ... after my ride with hooch today I might need reverse thrust brakes .. I don't think holes in the rotor will help ..LOL

 

[tuna boy]

Brian, any head way on drilling the brake rotors? Very interested to see how you make out.

 

[AApple]

Holes or milled grooves in rotors serve a couple of different functions. The main advantage is to give the gasses created by brake application a way to escape quicker. When brake pads are applied, the heat creates gasses from the chemicals in the pad friction materials, and that gas can build up on the surface, decreasing the pad/rotor contact. Holes/grooves give these gasses an escape route.
Another "advantage" to holes/grooves is that they keep the pads from glazing as much as they would normally. As the holes/grooves run past the pads, they scrape a tiny amount of material off, preventing a glaze build-up. This, in turn, wears the pads a little quicker than normal. So it's a trade-off of sorts.

Drilling holes in rotors can cause stress cracks to appear around the holes. Depending on the thickness and design of the rotor(vented/non-vented), the cracks may or may not cause a problem. :ahem:

 

[brianinpa]

tuna » Fri Mar 28, 2014 6:34 am[/url]":2ntzvxf3]
Brian, any head way on drilling the brake rotors? Very interested to see how you make out.

Not as of yet, too busy with polishing aluminum and repainting the :sensored: Rooster fairing and saddlebag doors for the 1200.

 

[mcgovern61]

My opinion (and it is my opinion only) I have warped 3 different rotors from a dragging caliper before I realized what was going on. These are overall pretty thin rotors. Does't drilling them increase the risk of warping faster?

 

[brianinpa]

mcgovern61 » Fri Mar 28, 2014 8:41 am[/url]":3et93owf]
My opinion (and it is my opinion only) I have warped 3 different rotors from a dragging caliper before I realized what was going on. These are overall pretty thin rotors. Does't drilling them increase the risk of warping faster?

That was my concern also and also why I wasn't even considering it until I got that parts bike and picked up a few spare rotors to play around with.

 

[brianinpa]

Today was the day for me to dust off this thread so I spent about 2 minutes in front of my drill press and realized that drilling a brake rotor would be easy enough to do. In the process I probably destroyed a 78 brake rotor, but hey, I don't own a 78.

I just used a simple step bit from Harbor Freight and just drilled out to the first step. Flipped the rotor over and dressed up the hole from the other side.

And just in case anyone is wondering or thinking I have some type of high dollar drill press, you would be wrong.

Now I just need to figure out a good pattern to use and do it for real on a set of 1100 rotors.

 

[dan filipi]

The step bits are great.
I've been using them for years instead of regular drill bits.
Keep them cool with wd-40 and they'll last much longer.

I have a nice empty spot (of all things) in my garage for a drill press.

One day I shall have one.

 

[brianinpa]

Dan I think I spent $10 for that one at an auction. I gave it a fresh coat of paint and it will out live me.

 

[dan filipi]

Gees not like the old days here when deals like that could be had.
Everything here is like retail, even the stickin yard sales!

 

[brianinpa]

Well... there was a reason it only cost me $10.

Before:

After:

 

[Jungo]

I know you are talking about the drill press and do not want to change the subject, but what strikes me more attention to me in the photo is the verdant landscape in the window. It's beautiful. :mrgreen:

 

[brianinpa]

Thanks Jungo... it thrives on neglect. :shock: :smilie_happy: