make bumber scroll

[littleperson404]

I can't seem to make my bumper button scroll just one click. I can do so with the trigger, but the bumper acts like i quick scrolling. Does anyone know how to do this?
If anyone wants context: i play star stable online and often use my scroll wheel to speed up and slow down. And of course to scroll through the trailering locations. Of course i can just click and drag the scroll bar, but i would like this to be easier