Exploding Rotors: why you do not drill

[Bob DAmato]

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[ Picked text/plain from multipart/alternative ]
The vents are symmetrical so the holes can be too.  The previous poster
was correct, they need to be in a symmetrical pattern otherwise they
have uneven cooling/heating/expansion and that spells nothing but trouble.

JShadzi at aol.com wrote:

>*This message was transferred with a trial version of CommuniGate(tm) Pro*
>IME, working in the aftermarket parts industry, hole patters are offten no=
t-symetrical to avoid the walls of the vents, often a symmetrical pattern w=
ill 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=
=3Den_US
>>>&bmLocale=3Den_US&market=3DUS&family=3DSoftail&model=3DFXSTS&num=3D1
>>>
>>>
>>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 hol=
e 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 mus=
t 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 a=
round this issue...
>>
>>cheers
>>Duncan
>>
>>
>>
>>
>
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>

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