[Triton88]

Its time i replace my rotors trying to decide between OEM and a two piece setup like: https://paragonbrakes.com/2-piece-ro...80-m4-g82-g83/

Most of the usage is on Track, got about 18,000 miles off the stock set of which 1200 miles were on track.

are there any cons to the two piece? Seems slightly increased up front cost, but lower long term cost?

thanks,

[Ximian]

Lower long term cost is questionable and I would even disagree at this point. There is no data yet showing that these rotors outlast stock rotors and by how long, so you'll have to assume they're even in wear. The stock braking system on our cars is very good, but the downside for the rotors is that they are drilled. Once the cracks propagate between the drilled holes, you'll have to toss those rotors, even if there is plenty of wear left on them. I would assume for most of us, we're reaching that point rather than the wear limit. The Paragon rotors are slotted which aren't as susceptible to the issues with cracking - ideal for track use. The cons of 2 piece rotors are the hassle of dealing with replacing the friction rings. Sometimes the bolts get stuck and you have to remove them carefully. I also don't trust the rotor hats past several years of track use and hardware installs, so those can be pricey to replace.

For the math part...

Assuming even wear - The 2-piece Paragon rotors are 1100 for the set and replacement rotor rings are 675 with the mounting hardware. You'll also need to pick up a torque wrench that can handle at a few inch lbs, plus your labor to replace the rotor ring, but not including that.

Meanwhile the stock rotors are $740 (per getbmwparts) for the front set without having to deal with replacing rotor rings and the hardware.

You'll need to change your friction rings 5 times after the initial purchase of the 2 piece rotors before you're close to being even on cost with going with the stock rotors. Rephrasing it, 6 stock sets of front rotors are cheaper than one set of Paragon 2-piece rotors and 5 sets of rotor rings.