Hi Gary:

No flicker at speed, some flicker at real low speed (i.e. walking the bike). If I may, I recommend going with a less expensive dynohub and more expensive light, um, like my set up--SRAM iLight hub, LightOn! dynolight. See BF thread, if interested. (After two full years of regular cyclocommuting use, I remain a happy user.)

Just down the road in Cary,
Erich