27.5+ bikes are a pretty new niche, but gaining some real traction (pun very much intended). The combination of larger wheels and wider tyres offer a fun, fast and super grippy ride. Struggling in mud and loose conditions? a ‘plus’ bike will leave your mates in your wake. Genesis’ Tarn 20 was reviewed by What Mountain Bike and, well, a glowing write up. Available as a frames or one of two complete bike options and in-store now.