BBK suggestion

[aozora]

Sorry but why are s2k rotors prone to crack ? Can you back this up with some examples for everyone to observe


Remember that a BBK comes with slotted/dimpled and possibly cross drilled rotors as standard too ?

http://www.s2ki.com/s2000/topic/7448...re-than-usual/
Knock yourself (yourselves?) out. Plenty more threads on this topic available too.

Yes but I'm talking about an OEM setup
From what I understand, cracking mainly occurs from sudden changes in temperature, metal fatigue or poor metal composition. A BBK rotor setup will ideally be thicker/larger/be 2-piece to allow for thermal expansion and be able to handle heat better through improved cooling vanes making cracking less of an issue. I'm guessing if you over-engineer a setup, you could probably engrave hello kitty on them if you wanted to and it wouldn't crack (braking performance however...) But it also depends on the metal composition and how it has been cast. A lot of factors... probably better to speak to a metallurgist really for a much better explanation

Anyway this page explains some of the points better than I can...
http://www.urgedesigns.com/brakes.html

slotted rotors only alleviate the problem??

Yes and cross drilled even worse - I had an engineer explain it to me through diagrams (not directly about rotors mind you but how to avoid weak spots in metal structures) but I cbf drawning diagrams haha.
The best way that I can (poorly) explain it is to file out a small groove in a pencil. Snap it. It snapped along the groove most likely right? Now snap a pencil without a groove. Which one was harder to snap?
Of all the cracked slotted rotors I've seen, the cracks develop within those "slots" (or on 2 piece rotors, they seem to develop small cracks near the alloy hat bolts and/or through the slots). That's not to say though that you shouldn't use slotted rotors at all... just preferably not on a OEM S2000 rotor setup

[9large]

whokid, if you're just cruising the streets or doing spirited driving/mountain runs, the stock rotors are more than enough. It's a common myth that gets propagated. The only time I've seen rotors crack is at the track where people haven't cooled down or warmed up their rotors properly (read, gradually). The brakes gets a TON more load at the track than even fast mountain runs. There's no way you would generate that much heat on the road, and if you do, you need to take that kind of driving off the streets. And I agree with aaronng - if you just want a BBK, then go for whatever takes your fancy - it won't matter - but you won't need a stronger brake setup for road speeds and driving conditions. After several years of tracking, I can tell you the stock setup is quite strong, especially for a single piston setup. Also, if you want a proper BBK (not just Spoon caliper posers), then 8 +45 is not enough. Sometimes, spoke design counts too.

If your pedal feel is getting soft, try flushing and changing the brake fluid. If you want a different/better feel to the brakes, you can also try changing the pads or fluid. At the end of the day, your limiting factor is your tyres. I've used various brake setups over the years, and it's always disappointing when folks spend $$$ on the notion that their braking is suddenly better, when they haven't considered the car's whole braking system, and all they do is potter around the streets and pose.

. . .

Yes and cross drilled even worse - I had an engineer explain it to me through diagrams (not directly about rotors mind you but how to avoid weak spots in metal structures) but I cbf drawning diagrams haha.
The best way that I can (poorly) explain it is to file out a small groove in a pencil. Snap it. It snapped along the groove most likely right? Now snap a pencil without a groove. Which one was harder to snap?
Of all the cracked slotted rotors I've seen, the cracks develop within those "slots" (or on 2 piece rotors, they seem to develop small cracks near the alloy hat bolts and/or through the slots). That's not to say though that you shouldn't use slotted rotors at all... just preferably not on a OEM S2000 rotor setup

That is relatively true for rotors with channels/slots or holes drilled post-fabrication. The cracks typically form where there is less structural integrity - from the edges of the slot or hole. Your analogy would also be more correct if you had to snap the pencil by standing on it, not exerting a directed force. The slots are used to channel hot gases (and even water) from the surface of the rotor, not to accommodate rotor expansion.