I’m going down the same road of hassle as Ken did in trying to find a suitable mudguard for a 100/90/19 Avon Roadrider. It ain’t as easy as it seems... the tyre has a large rolling radius, and is quite a large OD at its edges too. And, of course, tyres grow at speed. Does anyone know how much a tyre grows and how much clearance is needed? I’m thinking I need about 1/2”. Ken, would you mind posting a pic of your set up? Anyone else have any good ideas? All ideas welcome ... apart from changing to a smaller tyre or rim !!