[embee]

I have 16/44 on my curvey (15/44 is std).

16/44 puts the new gearing about halfway between original ratios, new 5th is like "5 1/2th".

It pulls this fine, I reckon if you really want to go this route and appreciate the effects, then 16/42 would be a viable gearing for motorway use without problem. It'll put your 5th gear quite close to the original 6th and the new 6th will be effectively "7th". Don't expect very much effect on economy, potentially there's a little improvement but it's not dramatic, the effect is more relaxed cruising.

For info, chain dimensions are traditionally in inches, the first number is the pitch (distance between pins) in multiples of 1/8", so a 5** series chain is 5 x 1/8" = 5/8" pitch. The second and third numbers are the width between plates (the nominal thickness of the sprocket) also in multiples of 1/8" but with the decimal point missing, so a *20 is 2.0 x 1/8" or 1/4", and a *25 is 2.5 x 1/8" or 5/16".

For road use stick to 525, you'll get better wear than with a 520.