It looks like 320mm are the only size for the 2 piece lightweight rotors availability for the ST. I really would like to use these for the 4.5 lbs savings per wheel if I can.
You will need to change caliper brackets then. Post up in the parts wanted. I'm sure there are a few out there with the parts needed. Lots have upgraded to the larger rotors. You are looking for 13 early 14 caliper brackets.
If you go smaller you'll lose some effective brake torque up front. So go to a better pad at the same time to make up for that. Not a bad upgrade I guess since you're losing valuable weight at the axle.
I ended up returning the rotors and requested that they make the 335mm rotors. Hopefully if they get enough requests, they will produce them in the future.
Their CEO I believe has an 2013 ST, thus their reason to even have aero rotors. More folks need to fill out that contact form, asking for 2015+ support.
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