STM Front Drag Brake Kits for 2004-2013 Subaru STi allow you to ditch the weight of your big, heavy Brembos and rotors and clears room to run 15" wheels and slicks for drag racing applications. We all know less rotating mass is the best way to free up power! The STM brake kits inlcude Wilwood calipers and your choice of the standard rotor or the lightweight scalloped rotor, custom STM aluminum mounting brackets, black anodized rotor hats, STM brake lines and all mounting hardware.
It doesn’t necessarily “rob” power but the less mass your engine and axles have to move the more power it will transfer to the pavement. So lighter rims/tires and brakes the more power it frees up.
Yes the rotating mass will be less with a brake rotor, but since the weight is so close to the center of the “spin” its difference isn’t huge. The rotating mass that will free up the most power will come from being able to run a lightweight tire, like a bias ply, since these brakes are designed from drag racing anyways.
Put some 24" inch rimmmzzzz on your Z and you’ll get a better idea
It is more beneficial to remove weight towards the outside
These are all made up numbers here
Say the rotor is 15 lbs less. That’s pretty good. I’m sure the weight distrubution is pretty close to the rotor hat and actual disc. But towards the outside is better. But what’s great , is you can now run smaller wheel and a drag radial or slick. My rpf1 17x9.5 combo is around 45lbs. My drag radial setup is 15 lbs less, with 12 of it coming from just the tire alone. That’s pretty huge.
That’s now roughly 30lbs per corner of weight saved in rotating mass. not to mention the gains from a improved 60ft while making more power.
If the 24" rims weighed in at same as lets say a current 17" rim, the 24" rim should be less rotating mass, since it’ll have less RPM to spin the same mass. Read the link I posted. It’s actually a good read on rotating mass and how most of the time, people are just cancelling out the effects.
