Topic: Disc rotor patterns

[thelowmax]

I'm going to drill out my brake discs and was wondering what my limitations are in regard to patterns.  Different size holes, how many, etc.. Is there a general rule regarding the placement, size, and number of holes? What about edge cuts? I see a lot of newer bikes with discs that practically look like doilies. I don't want to go that far but I would like to remove as much as I can without diminishing the functionality of the brakes. Any patterns and pictures would be cool.

[Mark M]

I imagine any holes will reduce the structural regidity to some extent, how far you want to go
is a question of how much of a risk you want to take. It's reasonably safe to assume that the
patterns most often used are fairly safe as you don't see lots of threads starting "I drilled my discs - now they have warped"
I would avoid touching the edge as the further you get from the center the more engery is applied to the material.

[seaweb11]

email sent  and
http://forums.sohc4.net/index.php?topic=9900.msg771941#msg771941

[BrianAdair]

hmm, I was wondering this also. Planning on drilling mine.

[turboguzzi]

pattern depends a bit on what are you trying to achieve.

In John Robinson's book motorcycle tuning - Chassis, there's a good explanation of the pros and cons.

Main problem with over driling will not be wrapping but cracks developing between holes and losing too much heat sink mass.

Personally' I had good experience with a daisy pattern that ensures that all the pad area is well swept by the holes, no ridges or grooves developed so far and pad wear is very even. similar to Jerry Rxman Griffin pattern in that link but with less "daisy lines"

Some of the other patterns shown in that link do not have overlapping of the holes so the pads will not be all swept = bad

[Howell]

The discs of my CB750F2 are also drilled , only for reducing weight.