A wider tyre must be harder to roll, surely? Apparently not.
Cast aside any intuitive thought process that you might harbour, wider does not necessarily mean harder to pedal – or slower – at all. In fact, the figures mount up in support of the opposing view.
In a recent road tyre test, the German cycling magazine, Tour, took an in-depth look as to how wider tyres (25mm and 28mm) stood up against the ubiquitous 23mm rubber, and some of the findings were interesting to say the least.
Before they started though, a level playing field had to be created. The market-leading Continental Grand Prix 4000S II and Schwalbe One race tyres were tested in 23mm, 25mm and 28mm widths, alongside wide tyres from five other manufacturers. They were all run on the same rims and initially at the same air pressures. The test was conducted on a travelling belt and measured on a level surface.
Cutting to the chase, Continental’s Grand Prix 4000 SII in 28mm width came up trumps with the least amount of rolling resistance (ahead of the same tyre in 25mm width). Even when deflated to offer a more comfortable ride, the difference in resistance was recorded as just one watt. So where does this leave us in choosing what tyre width works best for us? Do we just rush out and buy 28mm tyres?
Of course, there are subjective elements to be considered outside of comprehensive tests like these. Individual rider weights (we’re all individuals, remember), grip and handling, tyre compound, puncture resistance and price are all important considerations. Case in point: it’s worth noting that while the 28mm Conti tyre may have been the fastest in Tour’s test, the opposite was true of the Schwalbe One 28mm tyre, although the differences were relatively minor.
The key, however, is that a wider 25mm tyre allows the rider to drop the air pressure, without unduly affecting rolling resistance and performance.
How much pressure we choose to put into our own tyres will reflect on the performance of our bike, and it’s unlikely that no two riders will put the equivalent air pressures into their chosen rubbers. We find what works for us, depending on our weight and riding style, and we generally stick to it – creatures of habit that we cyclists are. As we’ll move on to, tyre pressure is a crucial factor when it comes to running a wider tyre.
There’s also the question of brand loyalty. Like bikes, we all have our favourite tyre brands and models, the arguments of which push long into the club run as to which tyres work best.
But the key take home point here is that the traditional thinking that a narrower tyre is fastest simply no longer stands up. Broadly speaking, you can enjoy the same – or a lower – rolling resistance with a larger tyre at a lower pressure, which in turn brings with it other benefits. Let’s go into that…