I just added to my stable, my 2009 Rockhopper just got joined by a 2009 Tricross Sport that I picked up courtesy of ebay. It comes with tyres that I'm guessing are about 25mm wide and fairly slick.
I'm used to Schwalbe Marathon tyres that are all but indestructible and I'm constantly conscious that these tyres probably aren't as indestructible. So I'm looking to swap them out sooner rather than later, but really don't know quite what to expect from the different widths of tyre on offer.
The reason for getting the tricross was for speed coupled with the capability for light offroad use. I don't expect to be racing the all-out roadies, and although I'd like to keep some grip in muddy conditions I'm not trying to turn the tricross into a mountain bike. So something of a bundle of compromises, and for now I don't want to put too much money into it because there's always a chance I'll decide to just stick with the Rockhopper and resell the tricross.
So here's the question... what difference will I actually feel in terms of riding, rolling resistance etc based on my tyres being wider or narrower, all else being equal? Something like Schwalbe's Marathon Extreme is available as a 700x35 only, but the Marathon Plus is available as 700x25, 28, 32, 35 or 38. I figure there's a reason for having so many options, just don't quite know what difference the options will make.
If it's relevant I'm about 6'4 and weigh 250 or so, and slowly dropping from there.