I ride a hybrid during the week, I ride to and from work on roads across the outskirts of Bangkok. At the weekend I swap my road tires for knobblies and go off-road with my two sons, who have authentic mountain bikes. Hence my choice for a hybrid.

I used to lead the pack but, as they and I get older, I end up following.

Lately however, I'm not even following, I'm stuck! I'm sunk up to the axles in mud, while they roll ahead only rim deep in it. Talk about plowing my own furrow, that's exactly what my narrow knobblies tires do in the soft stuff.

My hybrid bike has wide forks, capable of taking a fat tire, but the fattest I have found for my size wheels is 35mm. Please can you help find fat tires?