While 23mm tyres have long been standard on road bike, that’s changing quickly, with the pro peloton and amateur riders alike switching to 25mm rubber.
There are a number of benefits, with comfort chief among them. Wider tyres have also been shown to offer a comparative – or even reduced – rolling resistance than skinnier, 23mm tyres.
A wider tyre allows the rider to drop the pressure without unduly increasing the risk of pinch flats thanks to the larger air pocket. Reduce the pressure by, say, ten PSI (remember, the manufacturer’s recommended maximum pressure, normally 120 PSI, is just that – the maximum), and the tyre will be able to deform with imperfections in the road, compared to a rock-solid tyre which rattles any vibrations through the bike to the rider.
Many ‘race’ bikes have the necessary clearance for 25mm tyres, though check before you part with your cash, and a handful will take 28mm tyres. Sportive/endurance bikes generally offer more clearance, with most offering clearance for 28mm tyres. After all, they’re designed with comfort in mind.
The construction of a tyre is also likely to play a significant part in its comfort. A tyre made from a robust compound and with a low threads per inch (TPI) count may be more resistant to punctures but will skip over rough roads, whereas a tyre made from a softer, more supple compound will help soak up those imperfections, though it may be more prone to cuts and punctures. The best tyres have a dual or triple compound construction which offer the best of both worlds (not to mention rolling resistance and grip).