I Depends entirley on how u care for the bike.. straight out of the factory it will do about 40-45 Mph.. abuse its excerlent engine and it will easily go down to about 25-30 Mph. treat the engine well and ive seen them reach 65!!! if you look after your engine then there should be no problems you reaching 50 Mph. mine, had over £2000 spent on performance parts as i raced it (if u interested in starting racing mopeds defo get a road legal one, you drive it to the track, race it and drive it home :D ) and i had mine up to 92Mph which is pretty spectaculat our of a 49cc.