No, he's on a geared bike, but he has issues so he won't shift. Probably nothing we can do about that. He doesn't say what his gear-inches are. Umd's got it, I'm just too stupid.

To the OP - if you want to ride SS, calculate your gear-inches. Divide the teeth on the cog in the back into the teeth on the cog in the front and multiply by 27. The most common number for general use is 67-70. Find how to get a gear combo like that on your bike. Ride a gear like that. With practice you'll be able to spin over 100 on the flat for long periods. I can pull in that gear at 130 and I'm an old man. Just takes practice. You should be able to climb 10% grades in that gear, but not much more. There's always the "two-foot gear" for steeper bits.

You're just noticing the result of frequent riding. Some people call that training! Works good.