Hi all, Over the past 2 weeks my bike tyres have been deflating on their own - rear more than front. I don't have the numbers but it was noticeable enough when riding, especially pushing it around to park. The difference after pumping them up again was like gaining 100kW and losing 200kg. I pumped both tyres up to 250kPa as specified on saturday. Today morning i had to pump them up again. they were around 230+kPA (first reading on pump). What could be the problem? I checked for any obvious puncture marks and found nothing. I appreciate all help and advise, thanks.