Like I said previously it’s obviously personal preference. On the IOW I was comfortable all day. I didn’t grind up the hills or spin out on the descents. My gearing left me with bail out gears either side of what I used. If I had spun out or alternatively ground up hills then I’d of probably asked myself more questions. Cambridge is going to be a lot flatter than the IOW so if anything my margin of comfort will be even wider. My knee may let me down but that’s for another day...If you think something less than 52 is optimal for you then go for it. But for me that’s ideal for most days in England.