Changing gear ratios doesn't force a rider to spin too fast. That's at the rider's discretion. I'm 68 and I've used a 46/30 and 48/31 with a sram axs 10-36. Having a 40 tooth largest sprocket only creates larger jumps between the sprockets. I've gained enough strength in my 3rd year of my return to cycling to use a 10-33 cassette if I choose, but all that does is add a 14T sprocket. I've logged over 15,000 miles on replacement knees.