Most people by now have heard the proverb that the perfect number of bikes to own is n + 1.But while a full stable certainly does have its delights, many of us are in the situation where we really need n to equal 1. br Which raises the question: what sort of bike should that single one be? Well with such a range of riding out there available to be enjoyed, versatility has got to be key and for that reason we think a gravel bike is that bike.