I've had a speed wobble that starts at about 85mph and remains. At first you don't notice it much... its just a slight weave that becomes a wobble. Nothing like a slapper, and as said never becomes concerning. Don't tighten your grip, just apply a little palm pressure on one bar then the other and it'll improve. I've had this on bothe the original Siracs and the TKCs fitted. Whats been worse is that having just adjusted my tyre pressures they appear to be tram lining on the mis-shapen tyre blocks when coming to a stop at junctions or when turning at slow speed! This has now worn itself out, but for a week its been really disconcerting!