Thank you all for the feedback. The problem I have is that when riding in a group I get systematically dropped on climbs and seem to recover the lost distance on flats. Having done some reading it looks like a I have a low power to weight ratio. I am not a particular heavy rider (65kg or~143lbs) which means that probably my power output sucks.

The majority of training advice and material I got are either related to power measurement and need a powermeter or to heart reat intervals and keeping a good cadence arround 90 rpm. I have no clue how fast I spin, I compared myself with other riders in the group and the bracket range is quite wide between different riders. I tried spinning more uphill but this leaves me completely out of breath when trying to keep up with the herd.

To get back to my initial post: wouldn’t a cadence and heart rate monitor help to improve on my particular issue rather than just a stop watch and a hill? At least I would know if have to train either my cadence or torque more ...