Like a Catholic repenting their sins, tyres are your one way to cycling heaven. They are the only parts of your bike (we hope, genuflect) that touch the road. They roll, grip and cushion. They underpin how well your bike rides.
Admittedly a slow bike shalt not be made fast by tyres alone, but a thoroughbred will feel like a lollopy nag with a poor tyre setup. And looking around at so many bikes on the road, in the words!
