Need some help with choosing rotors.

I'm currently running 04 STi rotors (5x100) on my WRX that is fitted with brembos. What would be a good alternative to save few kgs? Will I get some improvement by dropping 2-3kgs from unsprung weight? Some claim that each kilo of unsprung weight = 30kg in kerb weight. Sounds fishy.

2 piece rotors are lighter by appx less than a kg ea, not much but will make a slight difference.

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221.7KW-ATW 498.5NM MMS ROLLER DYNO & BUILT BY STi NINJAS, BUILD #318/600

EBISU SUBARU, SHIBUYA-KU TOKYO

2 piece rotors probably cost fair bit of coin. So, what about normal DBA rotors, are they any lighter?

I wouldn't be surprised if they are heavier..

There is alot metal in the ventilation slots....

1 dba T3-4000 single piece rotor front 326 x 30 114pcd approx 9.5kg

1 dba t3-5000 two piece rotor same size approx 9kg

1 standard brembo rotor in same size approx 10kg

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Bye bye betty blue. Hello F6.

This was my 13" wilwood rotor when new. At 332x32 It is a few mm LARGER diameter than brembo, and also a couple of mm THICKER than brembo. And it wieghs 6.670kg, which is very light. The light wieght was great, but the down side is less thermal handling. And i actually upgraded to a 14" rotor because i was overheating the brakes at RAC once my driving skills improved.


The Biot rear rotors (brembo 2 pot fitment) were also lighter than standard brembo rotors, but the dufference was not as impressive.

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Doing it for all the wagons out there

Thats very light indeed. Do these come in 5x100 to fit Brembos? Did you buy them locally?

No. They are designed specifically to suit Wilwood 6 piston forged narraw superlites. FNSL6R. I bought them from USA. When i bought them, they came in 5x100 which i then had re-drilled for 5x4.5" by Russ Kapp. But i believe they now come on dual PCD from Wilwood.

The lightness was great for responsiveness. But as i said earlier, because being light, the brakes overheat while racing. So i went up to a 14" Wilwood rotor. (355mm.) Being radial mount calipers, changing disc size is easy. Simply put spacers on the dog bones and swap out the disc rotor ring to bigger diameter

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Doing it for all the wagons out there

What hubs are you running? Reason I ask is the pre 05 WRX hubs are prone to destroying wheel bearings. Post 05 went 30% larger and handle track heat significantly better without "pad knock off". If you have the smaller bearings a lower thermal transfer into the wheel bearing is extremely desirable.

Moving from standard to DBA 5000 two piece I noticed a good gain in acceleration response, braking and handling. This was with ultra light light 16x8 SSR Type C rims that were 5.48 kg each+R Spec tyres on a race track... Implying that some may not notice any gains due to already having overweight rims, poor rubber or simply obeying the road rules. Unsprung weight reduction is all win.

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Speak to Shane @ SMC Tyres, Unit 6/385 Sevenoaks St Beckenham WA 6107. Mobile 0413 128 087. Tell him Maddog sent you!

I have wilwood 2 piece rotors front and biot 3 piece rotors rear. In my opinion it does make a difference. But its not a big difference.

But the claim of 1kg unspung mass = 30kg regular mass is bullshit.
Id say that 1kg rotating mass is equal to maybe 3-4kg regular mass. At a rough guess.

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Doing it for all the wagons out there