Slotted or drilled rotors on street cars.
Discussion
SmoothRB said:
Seen quite a few around which I assume are factory standard? On Boxters etc.
Is there a point with putting them on street cars?
Slots act as scrapers / allow gas to escape - well that's the theory. Personally I'd never use drilled rotors on either a track or a road car - they act as stress risers and are prone to cracking.Is there a point with putting them on street cars?
Plain vented rotors with alloy bells would my preference.
ETA For the pedants that add that a lot of race cars due use drilled rotors - yes I know, but they can cost as much as road car.
Edited by rhinochopig on Saturday 1st May 13:38
I had drilled and grooved disks on my car when i purchased it. I don't know if it was because the car wasn't designed with them in mind, but they were bloody awful!
The judder through the pedal was terrible, although the sound was very cool as you stopped. It was like a very quiet zzzzz.
They also looked
The judder through the pedal was terrible, although the sound was very cool as you stopped. It was like a very quiet zzzzz.
They also looked

Stedman said:
I had drilled and grooved disks on my car when i purchased it. I don't know if it was because the car wasn't designed with them in mind, but they were bloody awful!
The judder through the pedal was terrible, although the sound was very cool as you stopped. It was like a very quiet zzzzz.
They also looked
This.The judder through the pedal was terrible, although the sound was very cool as you stopped. It was like a very quiet zzzzz.
They also looked

I run plain discs now.
rhinochopig said:
SmoothRB said:
Seen quite a few around which I assume are factory standard? On Boxters etc.
Is there a point with putting them on street cars?
Slots act as scrapers / allow gas to escape - well that's the theory. Personally I'd never use drilled rotors on either a track or a road car - they act as stress risers and are prone to cracking.Is there a point with putting them on street cars?
How many people driving to the shops get their brakes glowing red though and need the benefits?
MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
Got any evidence for that?MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
The reason why motorbikes primarily run drilled discs is due to weight, not their water shedding ability. Lower disc weight reduces unsprung weight and helps acceleration and direction changes as it reduce the rotational mass "gyroscopic effect".rhinochopig said:
MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
The reason why motorbikes primarily run drilled discs is due to weight, not their water shedding ability. Lower disc weight reduces unsprung weight and helps acceleration and direction changes as it reduce the rotational mass "gyroscopic effect".
king terrifying. Edited by Xenocide on Saturday 1st May 17:05
rhinochopig said:
MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
The reason why motorbikes primarily run drilled discs is due to weight, not their water shedding ability. Lower disc weight reduces unsprung weight and helps acceleration and direction changes as it reduce the rotational mass "gyroscopic effect".k.
warmfuzzies said:
rhinochopig said:
MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
The reason why motorbikes primarily run drilled discs is due to weight, not their water shedding ability. Lower disc weight reduces unsprung weight and helps acceleration and direction changes as it reduce the rotational mass "gyroscopic effect".k.
That's a pretty important weight saving...
warmfuzzies said:
rhinochopig said:
MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
The reason why motorbikes primarily run drilled discs is due to weight, not their water shedding ability. Lower disc weight reduces unsprung weight and helps acceleration and direction changes as it reduce the rotational mass "gyroscopic effect".Rotating unsprung weight is reckoned to be 5x as "heavy" in vehicle dynamics as static sprung weight is.
An increase in rotating sprung weight makes the steering heavier, reduces grip, reduces acceleration and lengthens braking distance.
flemke said:
warmfuzzies said:
rhinochopig said:
MarJay said:
Drilled discs clear the water faster from the pad surface meaning that they are better in the wet. Slotted is the same...hence why all modern motorcycles have drilled discs. They also provide better bite because there is more leading edge area attacking the edge of the pad.
The reason why motorbikes primarily run drilled discs is due to weight, not their water shedding ability. Lower disc weight reduces unsprung weight and helps acceleration and direction changes as it reduce the rotational mass "gyroscopic effect".Rotating unsprung weight is reckoned to be 5x as "heavy" in vehicle dynamics as static sprung weight is.
An increase in rotating sprung weight makes the steering heavier, reduces grip, reduces acceleration and lengthens braking distance.
I am an ex biker, awaitng opportunity .
k.
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