Used the 24 x 32 ( 18" ) gear in anger last evening.
There is a 20% hill called Sun Rising Hill going up Edge Hill in North Oxfordshire.
The sign at the top says 16%, the map says it's 18%. I measured it at 20% steepest on the curve.
Garmin data says 3.7 mph thereabouts; PowerCalc says 320 Watts for that speed on an 18% grade.
It took 12 minutes to get from bottom to top.
If I look up on the NASA curves to 12 mins at 320 Watts, I'm a 'Healthy man'
I'd been training in the gym by cranking the upright bike up to 325 Watts and riding it for 5 minute intervals alternating with 125 Watts.
Last evening, the real ride up the real hill felt a lot easier although it was for double the time interval....