What were the previous Dunlops BTW? If the tyre is used, it is slightly worn and should have lesser weight?
Check if your tyre is V-speed (240 kph). Normally the tyres of this size available in market are H-rate (210 kph). For the extra speed capacity, the tyre should be stronger and thus heavier. (Before somebody starts ranting about self-weight etc. plz note that wheel/tyre is a mass structure just like a dam or a railroad girder, and thus greater mass means greater load capacity, given all other factors remain same).
Also, if the tyre has different construction and weight then it has greater air pressure capacity. You can put in more air and see the difference. For one, Dunlop SP Sport 490 perform best (grip, stopping distance) with 35 psi all round, whereas car manufacturer recommended could be anything.
One thing you can do is weigh the tyre that came out and the replacement one and see the difference in weight. You can do this easily with a digital scale that has a range of 0-50 kg and least count of 5 gram. Ask your local general store wala to help you out.
OTOH, what is the date code?
You note here that you have recently also changed the brake pads. Maybe the brake calipers are jamming?