Gear ratios are simple enough to switch to your liking. As mentioned, the SRAM, Shimano and the, Sturmey Archer use the same cogs so that is a plus.
You can either make it easier to pedal by reducing teeth on the Sprocket, or by adding teeth on the cog.
That is for over-all pedal easiness, each gear will be equally easier.
I'm quite familiar with the Sturmey Archer hubs and not so much with the Shimano but the old Sturmey hubs (before 2010) use 2nd gear as the 1:1 direct drive. 3rd gear is 33% higher and 1st is 25% lower. For the Sturmey, that makes it easy to have two cruising gears and a granny for hills.
Im not sure if the Shimano is set-up that way. When Sturmey was bought in 09/10, the hubs were changed to 1st being direct drive which messes things up a bit for gearing changes.
There is a math formula for getting the correct gearing.
Front sprocket teeth divided by rear cog teeth times net tire height. (net is 1/4" less that standing tire height).
This will give a number that is called inch feet.
Industry normal for 1st gear is usually somewhere in the 50's I personally like +/- 58 i.f for first gear. Somebody pulling something or carrying weight may want a lower 1st.
Consider that the i.f. numbers for an average Schwinn 3spd with a 26" tire are 1st=50, 2nd= 67 and 3rd= 89. (using a 46t front, 18t rear)
Since the rear is usually the gear to change, you just plug in different rear cog tooth numbers until you get what you want.
I have a 3spd on a Schwinn lightweight frame using 27" tires. I use 2nd as the primary riding gear and 1st as a granny for hills, 3rd will get me around 20 mph with an easy gait. The formula was 48 teeth front sprocket divided by 22 teeth rear cog times by 27.25
That gives me a 2nd gear primary riding gear of 59.5. A first gear 25% higher of 44.6 which is a good granny number and 79.3 for third being 33% lower than 2nd.
I also have a 2 speed that is geared for me the same way.
Front sprocket 39, rear cog 19, tire 27.5"
That comes out to 55.9 for 1st and 74.5 for 2nd. Right in that sweet spot.
So Im not sure of the steps in a Shimano hub but the gear juggling is the same.
Last edited by macstuff; 08-26-21 at 02:46 PM.