tactics page

[g]

The first setting for a part is;

Flat: 2%
Mountain: -2%

Does this mean a 2% bonus for flat, so he only has to travel 98% distance or is it a 2% penalty, so distance travelled is 102%

[stefkeswoon]

It means that he'll perform 2% better on the flat parts, and 2% worse on mountain parts.
(It's the same effect as raising or lowering the effort of your cyclist by 2%.)