I have been riding a converted Kona Lava Dome on a 32/12 ratio into work every day for a few weeks - the journey has one big hill to negotiate which is only just do-able. With an occasional full backpack this hill becomes nigh on impossible.

I was going to revert to a 13 rear sprocket, which I had used for 2 months or so (I am a relative newcomer). Then I had the bright idea of maybe using the big (44t) chain ring (instead of the middle chain ring) with say a 18t rear sprocket.

I am hoping this will give me the best of both worlds: the speed on the flat (better than a 32/12) and the ability to climb up that hill.

Have I got my maths wrong?

this tool may help with your math:
https://software.bareknucklebrigade.c...it.applet.html

32x12 is 70.3 gear inches
32x13 is 64.9 gear inches
44x18 is 64.5 gear inches

Cheers. So a 44/18 will basically give me the same performance as 32/13. I think I'm with it now.

note that your speed will not have "speed on the flat (better than a 32/12)" because your gear inch is lower = less distance covered per pedal rotation; since you're currently dying on the hill, though, the loss of your top speed on the flats is probably worth the ability to conquer your hill.

??