^^ just to expand on that. It's the run up past the brake leavers. With STIs you're running cables inline with your grip. Once you bring the cable up on the side you're cutting into the crook of your thumb.
Ultimately you can just try it out under, see how you get on. Then go for a) if you don't like it.
Also fwiw you won't find any Riv bikes with understand on drops.
^^ just to expand on that. It's the run up past the brake leavers. With STIs you're running cables inline with your grip. Once you bring the cable up on the side you're cutting into the crook of your thumb.
Ultimately you can just try it out under, see how you get on. Then go for a) if you don't like it.
Also fwiw you won't find any Riv bikes with understand on drops.