Is bike juice safe to come in contact with rotors?

Bike Juice in the bottle is a concentrated degreaser most suitable for spray then scrub filthy drivetrains. It would not be needed direct onto a rotor. Sometimes you may get BJ overspray from drivetrain onto rotor but that is usually only a very small amount and does not cause a problem if rinse off within a few minutes. Diluting Bike Juice to 10% with water in bucket then foaming is useful as an all over bike cleaner using a brush. If you are cleaning wheels & stays then some of the foamy water may run onto the rotor or the caliper. This will not be a problem if rinse off within a few minutes. I would never spray concentrated Bike Juice all over rotors and pads and leave it to “soak in” for long period. A bike wash with BJ should only take about 10 minutes. Pads are most sensitive to cleaning agents and you should try and protect them during washing. Yes braking does transfer what is on a rotor onto the pads but using BJ diluted to clean is not going to leave sufficient residue on rotor to cause problems. After I clean a bike with Bike Juice I always use Avaqua (isopropyl) to flush out the calipers and wash any residual water. Avaqua is the only product which is OK direct onto pads.