Is it possible to change from road tyres to commuter tyres on a 2014 Giant Defy? Thanks
That model of Giant Defy will have clearance for almost any 700×28 tyres and some 700×30 models, but not all. If you are after a commuter tyre for increased puncture resistance, a Schwalbe Durano plus in 700×28 will be as good as any of the wider commuter tyres and will perform just as well on any sealed surfaces. If you want to ride a bigger tyre for better grip on gravel and unsealed roads, then your options are very limited.