My world routinely spins and slides off sideways. Never been diagnosed with Meniere's disease, but others in my family enjoy it.
There are times I cannot ride, or even figure out how to stand up, but overall, I usually can. I've learned to pretty much ignore what my ears are telling me, and use my eyes to orient with. Does make walking or riding in the pitch black kinda tricky.
I've learned many of my triggers, and what cures and crutches work reasonably well for me. Dark roast coffee for example just about guarantees screaming ears and a wildly spinning world (and it's not the caffeine, seems to be the oils of dark roasting). Good old dramamine generally muffles things enough for me to deal with riding or a day at the beach (waves wreak havoc otherwise).
Worse comes to worse, there are trikes and sidecars, or even sportscars. There are atvs and Jeeps. There are even landing gears for bikes (I used to make some myself, many years ago).
Ug, fun typing this because it has me thinking about it. So now I can really hear my ears screaming and feel the spinning. Time to go do something else and distract myself.