Discs - Drilled, Slotted or Regular

ninjag

Member
Age old question I guess, but what are people's thoughts on regular vented or drilled and also slotted discs?

I've got drilled discs on the front at the moment but they are nearing the end of their life and I also don't know what brand they are. I'll probably do the rears as well. They do make a slight noise under normal driving but nothing upsetting.

From what I've read drilled or slotted discs don't help with braking under normal conditions, but do help reduce brake fade. Is this true? They do look nice though lol
 

V6_Man

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Age old question I guess, but what are people's thoughts on regular vented or drilled and also slotted discs?

I've got drilled discs on the front at the moment but they are nearing the end of their life and I also don't know what brand they are. I'll probably do the rears as well. They do make a slight noise under normal driving but nothing upsetting.

From what I've read drilled or slotted discs don't help with braking under normal conditions, but do help reduce brake fade. Is this true? They do look nice though lol

Which car, engine etc.


Sent from my iPhone using Tapatalk
 

45bvtc

The Older I Get The Better I Was
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Gold Supporter
Age old question I guess, but what are people's thoughts on regular vented or drilled and also slotted discs?

I've got drilled discs on the front at the moment but they are nearing the end of their life and I also don't know what brand they are. I'll probably do the rears as well. They do make a slight noise under normal driving but nothing upsetting.

From what I've read drilled or slotted discs don't help with braking under normal conditions, but do help reduce brake fade. Is this true? They do look nice though lol

Go review MTEC :readit: Just purchased a drilled/protected set of four for our TT S Quattro @ £168 shipped. Using the same on our SQ5, drilled and protected. And each with Ferodo Eco-Friction Green brake pads - just brilliant for "me/us" and 'our' road use :racer:
 
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spartacus68

Registered User
Depends how you drive and what you expect from the car. I can't comment on drilled or slotted, as I've never driven a car hard enough to demand them. If it's for your S4, what was OE specification?

I did the brakes on my A4 Allroad earlier in the year and put on Zimmermann discs and pads all round ordered through Autodoc. Fronts are vents and rears are solid, but brakes feels responsive in all conditions. I used to rate Brembo, but now now. Fine for my Polo daily driver.
 

rum4mo

Registered User
I have only ever replaced regular front discs with ATE Power Discs, they had elliptical grooves on them - I chose them as they helped clear water of the discs, which in that car, a 2000 VW Passat 4Motion has quite heavy, had a 193PS 2.8 30V V6, and only 288mm front discs that had "trailing" callipers, ie callipers mounted behind the hub centre line, and that was recipe for ending up with marginal brakes getting flooded with water which was worst in winter when it was salty water. Fitting these grooved discs sorted that issue and I backed that up by retro fitting the extended parts to the wheel arch liners from the face lifted version of that car.
 

ninjag

Member
Thanks for the replies, maybe better if I address each one individually?

Which car, engine etc.


Sent from my iPhone using Tapatalk

Apologies for not mentioning the car, I thought it was in my profile but I've just realised that's the other Audi group I'm in, although I don't really frequent there. It's an S4 B8.5 Avant Black Edition stock engine with 19" wheels and Eagle 5, although I think I'll try MPS4 next time.


Go review MTEC :readit: Just purchased a drilled/protected set of four for our TT S Quattro @ £168 shipped. Using the same on our SQ5, drilled and protected. And each with Ferodo Eco-Friction Green brake pads - just brilliant for "me/us" and 'our' road use :racer:

Thanks, I'll have a look. Seems a little cheap, does that price include the pads?


Depends how you drive and what you expect from the car. I can't comment on drilled or slotted, as I've never driven a car hard enough to demand them. If it's for your S4, what was OE specification?

I did the brakes on my A4 Allroad earlier in the year and put on Zimmermann discs and pads all round ordered through Autodoc. Fronts are vents and rears are solid, but brakes feels responsive in all conditions. I used to rate Brembo, but now now. Fine for my Polo daily driver.

I've never heard of Zimmermann discs, is there any more information on them?


I have only ever replaced regular front discs with ATE Power Discs, they had elliptical grooves on them - I chose them as they helped clear water of the discs, which in that car, a 2000 VW Passat 4Motion has quite heavy, had a 193PS 2.8 30V V6, and only 288mm front discs that had "trailing" callipers, ie callipers mounted behind the hub centre line, and that was recipe for ending up with marginal brakes getting flooded with water which was worst in winter when it was salty water. Fitting these grooved discs sorted that issue and I backed that up by retro fitting the extended parts to the wheel arch liners from the face lifted version of that car.

That's a good point regarding grooves and water which I'd never thought of and being in Glasgow it could be very relevant. My front calipers are trailing and my rears are leading. I'm now going down the rabbit hole as to the differences between leading and trailing! lol
 

45bvtc

The Older I Get The Better I Was
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Thanks, I'll have a look. Seems a little cheap, does that price include the pads?
Just the discs, ninjag, and they should arrive today

However, go see: https://www.audi-sport.net/xf/threa...ounting-down-to-a-place-near-me.386559/page-6

And post #219 and that shows the MTEC's for our SQ5 @ £267 delivered

Pads again were Ferodo Eco-Friction Green (eBay) and they were £127 delivered (for an SQ5!!!!) both sets, see same thread post #150, page-4

So we've Ferodo Eco-Friction Green brake pads with drilled discs on our RS3, SQ5 and soon the TT also (already having Ferodo Eco-Friction Green brake pads of course)

So a very contented user of MTEC drilled brake discs and Ferodo Eco-Friction Green brake pads :thumbs up:
 

ninjag

Member
Just the discs, ninjag, and they should arrive today

However, go see: https://www.audi-sport.net/xf/threa...ounting-down-to-a-place-near-me.386559/page-6

And post #219 and that shows the MTEC's for our SQ5 @ £267 delivered

Pads again were Ferodo Eco-Friction Green (eBay) and they were £127 delivered (for an SQ5!!!!) both sets, see same thread post #150, page-4

So we've Ferodo Eco-Friction Green brake pads with drilled discs on our RS3, SQ5 and soon the TT also (already having Ferodo Eco-Friction Green brake pads of course)

So a very contented user of MTEC drilled brake discs and Ferodo Eco-Friction Green brake pads :thumbs up:

That's great thanks, plenty for me to look over now!
 

spartacus68

Registered User
As far as I know Zimmermann were OE spec on BMWs, but like anything you'll find good and bad reviews. I went for coated versions to cut back on rust. Think Textar are OE too on BMW. There's so many makes, but if it's German made that's good enough for me. Add in Meyle, etc.
 

ninjag

Member
As far as I know Zimmermann were OE spec on BMWs, but like anything you'll find good and bad reviews. I went for coated versions to cut back on rust. Think Textar are OE too on BMW. There's so many makes, but if it's German made that's good enough for me. Add in Meyle, etc.

Thanks. I never thought about Meyle and brake discs, I wonder if they do any for the S4? I'm replacing all the front arms etc on Saturday with the Meyle HD kit.
 

Simon

Registered User
I run zimmerman discs front and rear on my S4, though the fronts are upgraded to the b9 Calipers and a6 discs.

all groved or drilled discs do for you is allow pad gasses to escape, the results in a less floatly pad feel and slightly firmer braking. It is generally only really needed in repeated hard braking conditions and for normal daily driving utterly pointless. Drilled disks can lead to cracking under hard use so I generally prefer slotted even to the point of replacing my standard drilled discs on my GTR with slotted discs.
 

ninjag

Member
I run zimmerman discs front and rear on my S4, though the fronts are upgraded to the b9 Calipers and a6 discs.

all groved or drilled discs do for you is allow pad gasses to escape, the results in a less floatly pad feel and slightly firmer braking. It is generally only really needed in repeated hard braking conditions and for normal daily driving utterly pointless. Drilled disks can lead to cracking under hard use so I generally prefer slotted even to the point of replacing my standard drilled discs on my GTR with slotted discs.

Thanks, I'll keep that in mind about the cracking. What about water dispersal?
 

jdp1962

Grumpy Old Man
I used MTEC drilled discs on a B7 3.0TDi Quattro about ten years ago, with good results. More recently, when it was time to renew the discs and pads on the S4, I went for EBC drilled discs and redstuff pads. Again, I was very happy with both; way better than the OEM, not least because they were totally silent where the originals squealed like mad..
 

rum4mo

Registered User
water is not an issue for brake disks.
In what way?

Road spray can be a serious issue with brake discs and is one of the reasons why car companies started to introduce "disc kissing" to promote dry discs prior to using the brakes.

My old 2000 VW Passat was built before that was an issue, though even with newer cars with that system, salty water wetting discs, particularly front discs, in some models is still an issue despite shielding being in place - a very scary feeling braking in winter on a wet salty motorway when for the first few seconds you think that the car is accelerating instead of braking, then the discs and pads dry off and braking resumes.

When I formally quizzed VW Group about that, they maintained that drivers should always prepare for braking by applying the brakes lightly before they need to slow the car down. Which is essentially what they or Bosch introduced with the auto "disc kissing" routine, so they knew it can be an issue.
 

Keano04

Registered User
Personally I prefer slotted over drilled as cracking can be an issue with drilled.

You do get a “thrum” noise under hard braking with slotted discs ime. Not a big deal to me but may be to some.

Drilled/slotted are basically designed to help dissipate heat quicker. Slotted can also clear water off the disc surface too.
 

Simon

Registered User
If there is sufficient water on the road to cause a problem for brake discs it is far more likely you will lose grip from your tyres before braking becomes an issue.

drilled/slotted discs are more for pad gas dispersal than anything else.
 

rum4mo

Registered User
If there is sufficient water on the road to cause a problem for brake discs it is far more likely you will lose grip from your tyres before braking becomes an issue.

drilled/slotted discs are more for pad gas dispersal than anything else.
I agree in general in what you have written, but there were and maybe still are, some models that do suffer "brake wash out" in cold salty situations, and the A4 B5 and its VW Passat equivalent both did suffer from this at least in the VW Passat's until the FL model was brought out. VW Group recognised this issue and addressed it with "optimised" material in the pads and modified/extra front elements to cast water away from the front brakes. What they wrote in their reply to me was "this is not a VW Group issue, but an industry wide problem brought on by the removal of asbestos from friction materials" they added if I wanted to solve this problem, just visit an Audi dealership and request a set of front pads with the "optimised" later version of friction material. Round about that time, I was still reading AEX, and a reader from Dundee had written in to complain about this "exciting" situation that could arise in winter when driving on roads wetted with salty water, that reader drove an Audi A4 B5 roughly the same age as my VW Passat - at least I was not alone having experienced that problem. Round about that time, BMW and Ford and probably many other car makers started to fit better water deflectors to the fronts of their latest models probably to protect the front brakes. I've never experienced that with any other car before or since then.
 

ninjag

Member
I have noticed that in the wet the initial bite with the current drilled discs is very good. I initially wondering if I had four pot calipers or something. We do get a lot of rain here in Glasgow so lots of food for thought here, thanks.
 

rum4mo

Registered User
Maybe not so much an issue with drilled discs and any grooved discs that are used every day, but with my 2000 VW Passat 4Motion, I was initially using my car fitted with these grooved ATE Power Discs 5 days a week every other week, but latterly I only used it every other Friday - and that meant as it was always garaged, that salty water attacked the areas of discs at the edges of the grooves in a way that was not cleaned up the next time the car was used, so eventually I needed to replace the second set of grooved discs because mainly the inner surfaces were nearly completely permanently rusted up - that was annoying!
 
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