I just bought a medium cage rear derailleur so I could go up to 34 in the back. Along with a compact crank, that means I can achieve a 1:1 ratio between the front and back. I’ve read comments about why this is desired, but I don’t see what’s so special about the ratio other than (perhaps) efficiency in which the front and rear are working perfectly in sync. Is there more to it than this?
If this is indeed more efficient, what are the real world impacts?
It’s not really about efficiency more of that having a 1:1 is a “good” climbing gear. (especially for gravel) That’s entirely subjective, if you’re on the stronger/lighter side you might not need that much of a gear, if you’re the opposite you might want more of a gear.
But if I could go to say 36T on the cassette, that’s even better (For climbing) right? There’s nothing special about the 1:1 ratio in particular?
its about cadence on climbs
Depends. Much of this boils down to the actual cadence you apply in that lowest of low gears. If you are doing steeper climbs and stuck at 40-60 rpm… and also fighting fatigue from that related effort, having a lower gear ratio is necessary for a faster cadence for the same hill and rider weight (that should result in less muscular strain for the same speed).
This can all matter differently to different people. Riders with higher weight and/or lower FTP may suffer more on steep climbs from taller gearing. Switching to something that allows more of a “spin” can help them feel better during and after those steep efforts.