Tomos mirrors are 8mm, but the hole is not threaded. the mirror stem has a nut on top, above the brake lever perch, and another nut that goes on the bottom. Many scooters use 8mm mirrors, but they usually screw in, just like on a motorcycle, and the threads are not long enough to put a nut on the bottom. That will be your biggest problem, trying to find mirrors with enough threads. I don't recommend drilling out the hole any bigger than it is, as that will seriously weaken the plastic brake lever perch. You might be better off looking for used Tomos mirrors on eBay. New genuine Tomos mirrors are expensive. Peace. Jerry.