Checking the Trek archives, model years 2020, 2021, 2022 come with a 46T chainring and a 42 tooth cassette. I have a 2021 Allant 8s + and have added a 40T chainring and a Shimano M4100 11-46T cassette. This setup works perfectly for my needs. I needed the lower gearing as I live in a valley here in Michigan and there are grades up to 11% to leave the valley. If you are not in a hurry, gearing down increases the cadence which requires less boost from the motor resulting in less battery use and greater range. In warmer weather I typically average 15 mph moving average which translates into an average projected range of 55 miles. My longest actual ride so far was 52.49. The statistics from the Bosch system indicated that the remaining battery distance was 9 miles which should yield a hypothetical range of 61.49 miles. The remaining battery percentage indicated was 21%.