Frihetsmaskinen

Med en fällbar cykel tar man sig fram överallt. I X2000 första klass såväl som på enskilda vägar med förbud för motorfordon.

Prylkoll: Framdäcket heter Greenspeed Scorcher och är ett 40 mm brett däck utan mönstring. Det är det bredaste däcket som passar till Brompton. Jag tror inte på att breda däck rullar långsammare, tvärtom. Nackdelar är att de är tyngre och har större luftmotstånd. Jag cyklar visserligen otroligt, orimligt snabbt men jag tror inte däckets luftmotstånd spelar nån roll för mig. Men skönt att ha på grusvägar.

Bicycle Quarterly Tire Test
An objective repeatable test was performed that shatters a lot of long held beliefs about tires. I think most cyclists would agree that narrow high pressure tires are inherently faster. It’s too bad that notion is wrong. Interesting Jan found over 20% difference in speed between some of the tires he tested. Think about that 24kph instead of 20kph just by swapping out tires. Now add to that the fact the fast tires might be wider lower pressure ones that are much more comfortable.

Schwalbe Big Apple: Rolling resistance

Bike Race Info: Bicycle Tires Explained
What changes when the tire gets fatter is the shape of the contact patch. With a 20, the contact patch is a long oval. With the fatter tire, the contact patch gets shorter and wider. When a rider is using a skinnier tire, the long contact patch means he is flexing a wider arc of the tire casing, flexing more of the tire, causing more wasted energy from the internal friction of the tire and tube.

Bicycle tires – puncturing the myths
For an equivalent make and model of tire, Wheel Energy claim the 25mm-wide size will have five percent lower rolling resistance on average – the supposed average limit of human detection – than the more common 23mm one.