Cycling is today considered a progressive form of personal transport that offers nothing but advantages – with one unfortunate exception: the tire puncture. Schwalbe identified this problem at an early stage and has continually set new milestones in matters of puncture protection. For example, Schwalbe offers touring and city tires that can call themselves “flat-less”. For high-performance cycling, our Tubeless Easy Technology combined with tire sealant also sets new benchmarks in preventing punctures. And almost all other Schwalbe tires have an integrated puncture protection belt. Schwalbe tires for the future. Switch to 650b wheels and tyres are usually wider, to add extra air volume and comfort. 650b gravel bike tyres typically start at around 40mm wide and travel up towards 60mm, by which point, inches may be used to express the width. I’ve been running the Grand Prix 4 Seasons for almost six months now, and have covered the better part of 1,500km. Used on mountain bikes, these tires also go by the names: 27.5+, 650+, 6Fattie, or even just "Plus tires". ISO / ETRTO (mm)

In the past, 23mm was the typical width for most road tyres, and some tyres came in a 20mm width or narrower. Both indications are, however, very imprecise. A less wide 28 inch tire, e.g. with a tire width of 23 mm, which is usual for a road bike, has in fact only an outer diameter of something more like 26 inches. In the case of a tire width of 40 mm, Despite the ETRTO standards outlined above, manufacturing tolerances mean the fit between the tyre and rim can be tighter or looser than expected. The former is ‘fractional’, the latter ‘decimal’, and as a rule decimal and fractional tyre sizes that look the same are not.

Nowadays, bicycle tire sizes are all marked according to ETRTO (European Tire and Rim Technical Organization) standard. However, older English and French tire size dimensions are still used as well. On the bike, the tyre offers up good grip, especially in the wet. Tip your bike into a downhill bend, and you get sure-footedness and confident adhesion. In testing, I’ve considered it a small price to pay for the overall longevity and performance of the tyre. Plus, outside of summer weather, many will find it preferable to the heightened risk of punctures you get from an even lighter construction.

Almost all road bike wheels are 700c (with a beam diameter of 622mm), although some bike brands fit 650b wheels (with a bead diameter of 584mm) to some of their smaller-sized bikes, so they can maintain a similar road bike geometry to larger frame sizes.One final point – while millimetres are often used to measure or refer to the width of a road bike tyre, its actual width when inflated will depend on manufacturing tolerances, the rim width and tyre pressure.