Rotor Question

[TnBlkC230WZ]

Most OEM brakes on sports cars and the aftermarket kits come with 1 inch or thicker rotors. Most of the Wilwood kits come with a .81 rotor. Just curious as to why they get by with a thinner rotor. Is it because the aluminum hats disapate the heat better or some other reason? I know the lighter wieght has to help performance, but I'm wondering if there is a down side.

[Apogee]

Rotor mass is directly related to the operating temperatures of the rotors. The more massive the rotors, the slower and less severe the temperature swings. The downside is the additional rotational inertia, but better braking and capacity (up to a point) are worth the trade-off for most people. Other pros include the ability to run a lower temperature range pad, longer rotor life and greater braking capacities for those who push their cars hard for extended periods of time.

I think you'll find that most of Wilwood's more serious brake kits come with thicker 1.1", 1.25", 1.38", etc rotors, especially those intended for vehicles in the over 2500# weight category that are intended to see some track time.

Tobin
KORE3

[TnBlkC230WZ]

That's what I always thought. I guess since my rotating weight will be have that of a new Camaro and I'm 500 lbs lighter than a new Camaro, I don't need that much rotor.

[Apogee]

Not knowing how you intend to use your car (or even what your car is), it's tough to say what you may or may not need. Even most of the factory discs on GM muscle cars from the 60's and 70's used 1" or 1.25" thick rotors depending on the application, and there's a reason for that, so I wouldn't assume that you would be fine or happy with less if if you can "get by" with it. IMHO, it would be better to err on the side of caution and have surplus braking capacity versus a deficit, but I'm a "brake guy" so I won't pretend not to be biased.

If your brakes are marginally sized for the type of driving you do, the best thing you can do to increase your braking capacity without upgrading to larger rotors is to add cooling ducts to get the most from what you've got. There are a lot of kits in between the smallest Wilwood kits and the 14" Brembos on the new 2010 SS Camaro, assuming that's what you're referring to, so I'm not sure where you were going with your comparison. My $.02 FWIW, get the biggest brakes you can fit in your wheels and budget...you can never have too much brake.

Tobin
KORE3

[TnBlkC230WZ]

It is in a 71 Nova that is primarily a daily driver (I drive it every day to work) with occasional autocross time. I've selected a Wilwood Dynapro 6 kit with 12.2 inch rotors, which is the largest I can comfortably fit. I have just under 15 inches of inside wheel clearance. I looked long and hard at the Kore3 C5/C6 kit, but it would be too close of a fit, so I opted for the Wilwood kit. Everything thing I've read about them was very positive.

I'm always trying to reduce unsprung weight. The Wilwood kit should help as well. My curiousity about the thinner rotors kept comming back, so I thought I'd post this question. My logic is that the aluminum hats and hubs are a better heat conductor to keep things cool and the lower rotating mass will create less heat. The rotating mass is considerably less than many new cars. Probably 30 - 35 lbs less than a new Camaro when totalling the wheels, tires, hubs, and brakes.