Typical cruising gears are in the 80s gear inches and climbing gears are 30s gear inches. However, they will
depend on personal fitness, and preferences. Use your existing set up as the benchmark for any changes.
Please also remember to consider the impact on chain length.
Brompton BSR (S-RF3) 3 Speed gear ratio/range is here.
Brompton BWR 6 speed gear ratio/range is here.
* 12T sprocket is available only in N version (with 9 spline driver, as with BWR)
† 17T sprocket can only be fitted in a dual sprocket application, and may scape the rear frame. In such case, the 17T sprocket needs to be file down slightly.