Hi there. New to this thread, and pretty much to cycling to (after about 30 year break). Recently got rid of my old, heavy, full suspension monster and bought a 2007 Giant MTB. I don't intent to ever be hurtling down any mountains, but, being quite heavy myself, I like the feel of mountain bikes better. I mainly will be up and down curbs, and some light off road stuff. I got a punture (well wrecked the tyre on the back) and replaced it. the one that was on it was a 26x19.5 and the new one is 26x2.1. Here is my question. the new tyre looks much bigger. Is there any draw back in this? Will it use up a lot more energy to cycle, will it be slower, or does it not make that much difference? Looking forward to getting lots of usefull cycling info about lots of stuff at this site.