This jacket is over-sized to fit over your protective riding jacket. We suggest you choose the same size you wear in the jacket you plan to wear under this rain jacket.
If you plan on wearing this rain jacket without a protective jacket under it (for non motorcycling sports) then choose one size smaller than you normally wear in men’s clothing.
The pants are not as over-sized as the jacket since riding pants aren’t generally as bulky as the jacket (with shoulder/elbows armor and all). I’d advise you buy the size you normally wear in pants. When in doubt, buy one size larger. Inseam lengths on the regular size pants is about 32” on the smaller end of the scale and 33” on the larger end of the scale. Tall sizes are about 2” longer than the regulars across the board.