# Rotor disc's any good ?



## thehornster (Apr 29, 2005)

Are these rotor discs any good guy's ive not seen them before.










http://www.blueflameperformance.com/car/rotordiscs.asp










TT 1.8T 2WD 98-> FRONT PAIR RD53971 312 X 25 Â£201.98
REAR PAIR RD53955 232 x 9 Â£146.64 
TT 1.8T Quattro 98-> FRONT PAIR RD53971 312 X 25 Â£201.98 
REAR PAIR RD53968 239 x 9 Â£148.40


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## ctgilles (Jul 5, 2005)

Hmmm, unique design and does look kinda cool 8) 
As to performance, I wouldn't have a clue... Hope they are good, because I want them too now LOL


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## thehornster (Apr 29, 2005)

Have you all seen them is that why your quiet ?? i'm after uprating my OEM brake so im looking for ideas :wink:


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## deckard (Apr 4, 2005)

There's a danger it could all turn out looking like this though!


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## slg (May 6, 2005)

> There's a danger it could all turn out looking like this though!


only if iceman gets to photoshop it 

Discs look different though


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## Rhod_TT (May 7, 2002)

I just replaced my standard discs with ATE Powerdiscs from Eurcarparts (Â£110 for the front pair). They've got a funny groove around them which does a few different things (according to their website) but as they were nearly the same price as the OEM replacement discs then I thought I'd give them a try. And with the new RedStuff pads the brakes are so much better than the standard discs and Greenstuffs they replaced. And ATE are the same manufacturer as the TT calipers.


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## John-H (Jul 13, 2005)

They do look different! I'm not sure about performance however. The edge of the disc was been reduced to give that serrated feature. Given that there's not much room between the edge of standard disks and inside of the calliper that must mean that there's less swept area than a plain disc, by the amount cut away. I'm not sure how air flow will be affected.

I was once persuaded against my better judgement to get some Black Diamonds, which were black, cross drilled and had spiral cuts, mated with Mintex M171 pads (which I knew were good). They were a vast improvement on my worn out discs and pads. I found out however that the black wore off, the cross drillings and spirals soon blocked up with brake dust and were innefective, only serving to wear out the pads quicker and reduce swept area. They also rusted quicker from the inside. When they were worn out I replaced them for standard discs and the same competition pads - guess what? - They were a vast improvement on my worn out discs and pads! (New discs and pads always perform better!)

Cross drillings are for motorbikes to displace water - you don't need them on cars because the disks are not exposed to rain like a bike.

In my experience fancy looking discs are only for looks and not performance - and they'll cost you a packet. Discs don't last long these days either because of the more abrasive non asbestos pads. Stick to the standard plain discs and spend your money on something worthwhile. Performance pads however are worthwhile.


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## Andyman (May 6, 2002)

This design has originated from the high performance bike world. The idea is that the pads are not in contact with the disk for 100% of the time. This is supposed to allow the pad to expand at the point it isn't in contact and then bite again when it comes back into contact. Its a technique that has also found its way into top end mountain bike disk brakes.

Andy.


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## Rhod_TT (May 7, 2002)

http://www.conti-online.com/generator/w ... sc_en.html


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## John-H (Jul 13, 2005)

Hmmmmm.... A practical test would be for two identical cars (or the same one with the brake rotors swapped) to do several 70mph to 0mph stops with full accelleration in between until brake fade sets in. That would test the heat capacity and air cooling efficiency of the rotors. You should at least get 4 or 5 stops before your discs glow and the pads fade.

I'm not convinced the pads coming on and off would give you a better average friction coefficient than being in contact all of the time. But even if it did it would just mean you don't have to press the brake pedal quite as hard. Of more importance would be heat management and fade resistance which is a function of the mass/heat capacity of the rotor, the air cooling efficiency and the pad fade resistance. Friction is more easily changed by the pad material.

Any takers for the test?


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## HighTT (Feb 14, 2004)

John-H said:


> They do look different! I'm not sure about performance however. The edge of the disc was been reduced to give that serrated feature. Given that there's not much room between the edge of standard disks and inside of the calliper that must mean that there's less swept area than a plain disc, by the amount cut away. I'm not sure how air flow will be affected.
> 
> I was once persuaded against my better judgement to get some Black Diamonds, which were black, cross drilled and had spiral cuts, mated with Mintex M171 pads (which I knew were good). They were a vast improvement on my worn out discs and pads. I found out however that the black wore off, the cross drillings and spirals soon blocked up with brake dust and were innefective, only serving to wear out the pads quicker and reduce swept area. They also rusted quicker from the inside. When they were worn out I replaced them for standard discs and the same competition pads - guess what? - They were a vast improvement on my worn out discs and pads! (New discs and pads always perform better!)
> 
> ...


Well said - People so often compare their new brakes with their
old worn set-up. Drilled discs do have better initial bite when wet and
indeed better initial bite when cold; but no advantage when really hot.
There can be cracking problems with drilled AND vented discs;
the heat travels across the thin disc to the hole and then has nowhere to go; solid drilled discs are stronger.

Grooved discs are better on the track (when hot) as they do allow the gases released from the binder material to escape better.
I think that Rhod_TT's ATE discs would be a very good road (where let's
face it you shouldn't be driving in a manner to induce fade) 
and Track Day disc - they will be my next replacement.


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