The speeders give you far too much speed, the velramp is designed in a way that the faster your lateral speed is internally, the slower your real lateral speed will be. So speeder sets your internal speed waay too high, after the velramp that becomes 0. As your internal speed starts decreasing the effect of the velremp eases off, and you start moving faster, until you get to the peak speed then your speed starts behaving as one would expect with your internal speed matching your speed after the velramp