Exploding Rotors: why you do not drill

[JShadzi at aol.com]

IME, working in the aftermarket parts industry, hole patters are offten not-symetrical to avoid the walls of the vents, often a symmetrical pattern will run into the vent walls, which is a very structural part of the rotor, hole patterns are adjustend to prevent this.

HTH,
Javad


>> > I would challenge anyone to find pictures from a reputable site or brand
>> with discs which have
>> > been drilled in anything other than a symmetrical fashion...
>>
>> http://www.harley-davidson.com/PR/MOT/2003/03_model_enlarge.asp?locale=en_US
>> &bmLocale=en_US&market=US&family=Softail&model=FXSTS&num=1
>
>ask and you shall receive...!
>I guess that proves the point!
>does anyone have a better picture which shows the entire disc..?
>
>> Drilled rotors do not have to have their holes in any clearly repeating
>> pattern.  They only need to have the center of mass be at the center of the
>> rotor ("balanced").
>
>For balancing, yes, but for thermal and stress loading, any irregular hole positioning will result
>in stress concentrations which _will_ weaken the disc.
>Obviously in the case of HD, this was not the deciding factor, and it must be vibrations or
>resonance that prompted them to use their rather unconventional pattern...
>
>thanks for the info, very interesting, just still trying to get my head around this issue...
>
>cheers
>Duncan
>
>