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My 928 4.5L has standard rear disc brakes and S version front disc setup. I am now at the point of buying the discs. I can buy EBC discs for a good price now. Full set front & rear with pads: EUR 745 or just the fronts: EUR 425. These are called "sport brakes"for whatever reason. I think they are cross drilled.

Alternatively I am offered EBC discs (I think standard, not cross drilled) without pads, front and rear for EUR 485 or EUR 319 just the fronts.

Are the cross drilled rotors worth the extra money? And should I buy the pads as well? I already have a new set of Pagid for the rears and Guttmann for the fronts on the shelf.

John Veninger

I don't like cross drilled rotors. For the street they look "cool" and really don't serve much of a purpose.
On the track they tend to crack and/or make the rotor wear uneven.

Vilhuer

They were invented for racing where disks see maybe one full race and not more. Since street car owners want "race" stuff they are popular. In reality they only cause problems and don't bring any benefits compared to other options. Grooved disks would be much better for normal street and track day use but they are not as sexy.

linderpat

the best stopping power occurs with a flat disc, no grooves or drilled holes. It's all about surface area. Plus they last longer.

Adamant1971

I have three years and 10k on my slotted and drilled rotors with no issues. I actually use the same brand on our Honda Odyssey that chews through factory rotors, these rotors have been the only ones that have lasted any time without warping.

The theory behind holes or slots is the removal of hot gasses, to allow for cooler brake temps.

My 2 cents.

Imo000

The holes were needed before the pad technogy made them obsolete.

GlenL

So many brake experts!

The holes look cool and if your wheels show them then I'd get them. Because of cool.

Getting sets can be a cost-saver but price it out for what you want.

Adamant1971

The only thing I'm an expert on is spending money. Agree they are more for looks as the 928's brakes are very well designed in stock form.

123quattro

This is the correct answer. New pads don't off-gas like 80s pad technology.

MainePorsche

Great discussion.
Thanks.

Speedtoys

Pads havent gassed for 50yrs.


If rotors are being eatn thru, its the pads. If you think they are warped, its just pad deposits from being out of temperature range.

Adamant1971

Yep, I'm aware of that and that has been the issue as the van is severely under braked. I'm just so pre-programmed to call it warping (my bad). But with the drilled and slotted rotors my brake temps are down now with one year on them. The longest I have gotten out of any rotor.

Now back to Porsche related content. I think they look cool, and for the amount I drive the car it works fine. But I do agree with others on the flat rotors lasting longer. Especially if you are driving daily, or in the winter.

Imo000

I have a neighbour's Pontiac Torrent that regardless how many high speed emergency stops I tried to do to scrub off the pad deposit, it didn't make a difference. One of the front rotors are causing a vibration when the brakes are applied at highway speeds. I'm starting to think the rotor (6months old) is actually warped.

TrackDays247.com

Avoid the holes.

MainePorsche

Does the same apply to slotted ?