I have a 2016 S60 Inscription. I'm thinking about upgrading from the standard 300 to either 330 or 360 mm rotors. Does anyone have an opinion on whether the money invested is worthwhile? Any brands I should consider? I'm not a heavy duty driver so it's not because of extreme driving conditions, but more for safety reasons. I think the 300's are minimal and brake rotors should be larger to begin with.

 

You can put larger discs on, or you can put a big brake kit on - but you probably won't notice - other than the balance in your bank account. The brakes Volvo uses are designed to stop the car. If you start redesigning the brakes - are you going to redesign the rears also?

I put the s80 larger rotors on my xc70, I had the rotors in stock and they had been sitting on the shelf for years. (not a quick seller) I didn't notice a difference (in braking ability) but years later when it was time to replace those rotors again - and the parts catalogs were incorrect! (duh) It was a little bit of a pain to figure out what the correct rotors were.

 

the idea behind larger rotors is better heat dissipation that may arise in extreme conditions like towing or driving in mountains. For everyday driving including an occasional panic stop, the OEM rotors will stop the car in the same distance as larger after markets on the first stop. Its after 2 or 3 consecutive panic stops (like those done when Car and Driver etc are testing performance for track day) where brake fade would start to crop up. What is really going on during a panic stop is the surface of the brake pad gets hot enough to boil and create gasses that cause the puck to ride away from the rotor - losing grip. You can mitigate this by putting holes or slots in the rotor just like a Porsche (bonus for painting the calipers red). Another factor is brake pad material. Pad can be organic (most OEM pads here), semi-metallic or ceramic. Again the idea is the difference in the pad material comes into play during hard stopping since organics would produce more boiling than say ceramic. Problem is for day to day driving, the organics have the best "bite" (ie the feel when you first press the brakes and ceramics the least, meaning it takes more pedal pressure for routine rolling up to the stop light braking. This is why most OEM pads are "softer" organic pads - they give the best daily driver experience. So if you really want to have better mountain braking you can go with ceramic pads and drilled rotors but the brakes won't have the same feel day to day. Personally I've tried all combinations over the years and eventually I wound up recommending OEM Volvo pads on name brand rotors like Zimmermann or Brembo.