I changed my tyres for a more track focused type (NS-2R) ahead of a track day the next day and I think that since then I've noticed that I seem to clip the ground when I come down speed bumps and also there's a large dip in a road with a double compression at the bottom which has also started to be problem. These are slight connections with the soft plastic deflectors on the underside at normal previously OK speeds so not a major deal but something has clearly changed.
I'm at something of a loss to explain it. The new tyres are exactly the same size. The sidewall is stiffer than the old tyres and the load rating is the same.
They did provide much more grip than the PSS on the trackday. The brakes were able to be applied later and harder. It did occur to me that maybe the loading that can be applied by the brakes in conjunction with these tyres has effectively added compression loads to the springs that weren't possible previously and now they've settled at a new ride height. Other than this I thought that there could be a another common component that has affected bot sides at the front.
All speculation of course. If anyone has any other notions I'd be happy to here them!
