Why Not To Use Drilled Rotors
03-08-2009, 07:50 PM
#31
Rennlist Member
BTW, Porsche "drilled rotors" are not drilled at all. They are cast and then machined. The "cheaper" drilled rotors are just that drilled. This leads to a localized weakness due to the heat from drilling, stress fractures, etc... Just my .02.
03-09-2009, 12:52 AM
#33
Rennlist Member
I'm sorry, but we would need a lot more info about this accident to determine causality. While I am not a huge fan of perforated rotors, the conclusions drawn by the OP are not borne out by the skimpy facts posted.
Professional Racing and Driving Coach
Professional Racing and Driving Coach
03-09-2009, 11:21 AM
#36
Three Wheelin'
Naturally "drilled" rotors are going to be prone to failure around the holes due to the inherent stress caused. They are much more prone to cracking if the holes are machined in due to the residual stresses from the drilling process. This makes them more prone to cracking. Holes that are cast in still produce stress risers, but because there is no residual stress from post machining they are more reliable and more resistent to cracking.
If you're running drilled rotors checking for cracks should be done regularly at the track. Its easy enough that there should be no reason not to.
03-13-2009, 06:26 PM
#37
Former Vendor
YeOlde data point:
Virtually NO top level race teams use rotors with holes in them.
To me, it's a relic of the past, an 80s thing that needs to just...go away.
Ideally the Chevroned pattern rotors are the ones to use - very little chance for cracks to form from a chevroned rotor - much less than holed and quite a bit less than slotted. Stress risers = bad.
Up to that point, the best you can do is *examine* your equipment via hands-on inspections to prevent a possible tragedy to machine...and maybe man too.
Virtually NO top level race teams use rotors with holes in them.
To me, it's a relic of the past, an 80s thing that needs to just...go away.
Ideally the Chevroned pattern rotors are the ones to use - very little chance for cracks to form from a chevroned rotor - much less than holed and quite a bit less than slotted. Stress risers = bad.
Up to that point, the best you can do is *examine* your equipment via hands-on inspections to prevent a possible tragedy to machine...and maybe man too.
03-13-2009, 06:53 PM
#38
Rennlist Member
virtually no top level race team uses 14 heat cycles on their tires, dual adjustable shocks, rubber bushings, single piston calipers, solid rotors, and countless other things.................. Doesnt mean they are all bad. Granted technology has advanced in many areas, but I dont think some of the old stuff is all that bad or unsafe if used with precaution. cast hole rotors are better than flat, and as good as most slotted rotors. The new cheveron'ed rotors are ususally 2 piece and much greater in diameter.
mk
mk
YeOlde data point:
Virtually NO top level race teams use rotors with holes in them.
To me, it's a relic of the past, an 80s thing that needs to just...go away.
Ideally the Chevroned pattern rotors are the ones to use - very little chance for cracks to form from a chevroned rotor - much less than holed and quite a bit less than slotted. Stress risers = bad.
Up to that point, the best you can do is *examine* your equipment via hands-on inspections to prevent a possible tragedy to machine...and maybe man too.
Virtually NO top level race teams use rotors with holes in them.
To me, it's a relic of the past, an 80s thing that needs to just...go away.
Ideally the Chevroned pattern rotors are the ones to use - very little chance for cracks to form from a chevroned rotor - much less than holed and quite a bit less than slotted. Stress risers = bad.
Up to that point, the best you can do is *examine* your equipment via hands-on inspections to prevent a possible tragedy to machine...and maybe man too.
03-13-2009, 06:55 PM
#39
Rennlist Member
what is better as far as quality. zimmerman cast hole rotors or Porsche OEM cast hole rotors? Ive used Zimmerman for years and punish the heck out of them. I pull them twice a season when they start to crack at the holes. I wonder how the porsche rotors will do. they look better quality , due to the painting of the exposed non contact surfaces though.
mk
mk
03-13-2009, 08:51 PM
#40
Rennlist Member
I have to vote with VR on this one, what came first the chicken or the Egg. Did the rotor failure cause the crash or the crash cause the rotor failure. I guess you had to be there. Anything is possible but I would say that most rotors show signs of fatigue before failure. Having said that I am a big supporter of solid rotors. Give me heavy metal. If i have to have a little extra weight, lets put it on the braking system.
03-14-2009, 01:08 AM
#43
Former Vendor
Top shelf rotors - I took these pictures at Daytona 24 hrs 2007:
1) Slotted - notice the nice big edge margin?
2) Not Chevroned, but close (the chevroned rotors have Vs similar to these lined rotors
1) Slotted - notice the nice big edge margin?
2) Not Chevroned, but close (the chevroned rotors have Vs similar to these lined rotors
Last edited by TrackDays247.com; 05-05-2009 at 01:57 PM.
03-14-2009, 10:09 AM
#45
Rennlist Member
Any recommendations on management of rear rotors. I have Protosport slotted on the front of my GT3. Factory rears, which have some fine crack developing from the holes. I do maybe 8 +, DE's a year, driving to the track. Rears have 12000 miles and a dozen DE's.
Replace soon? Use Porsche cross drilled, aftermarket cross drilled or slotted? I new to this aspect of track days.
Thanks
Replace soon? Use Porsche cross drilled, aftermarket cross drilled or slotted? I new to this aspect of track days.
Thanks