I decided to pump up my tires as I had to carry something heavy on the Brompton today. (Christmas present.) I went to the Brompton site to check what the tyre pressure should be and I discovered that I have been cycling on almost half the pressure I needed. Cycling on the wrong pressure makes cycling a lot harder and damages the tyres. Previously I have just been checking the pressure by poking the tyre. If I can dent it then pump it up. Wrong. Tyres need to be very very hard.