I'd never use my BCR, not even when hill climbing.
40kkm/hr is like REALLY fast.
Well some people only SCR when returning to training. 40 Kracking Kilometres per hour is a certainly cracking tailwind.
You've gone all Karrak Karnival on us. Has Moreen gotten to you?
40 kilokilometres is hoooge! I like my SCR but was BCR all ride today - mind you, cadence very high these days. I'd like to think its because I ride better technically but suspect it's more because I can't push the skin off custard any more.