Geri ,that is the result when ground effect downforce is removed suddenly
Don the front wheel 'tyre assembly is subject to 3 forms of drag
1. form drag ,basically its shape ,push a wheel at speed through the air and it creates drag ( look at it as NOT rotating ) the fairing (fender ) decreases this drag
2. rotate the wheel at any velocity and it creates drag ( even when stationary and rotating) placing a fender around the wheel with with a pumper stoper ( a means of limiting the pumping drag / losses ) will reap gains in mph
3. form drag from side winds ,unfortunatly the better the aerodynamics for forward motion the worse the effects of side winds
it will also experence lift or downforce depending on the fenders construction
aerodynamics is a bloody complex subject
in this pic you can see the fender I made for my landspeed bike ,as well as all the aero bodywork ,only problem is none has beeen wind tunnel tested
gary