Looks like my back tire is getting a flat spot and is getting quite chewed up from a lot of glass. I've been reading a lot about the Continental GP4000's here and I wanted to know if the tire would be ok for mostly recreational riding and not racing? I ride about 50-100 miles a week, about 30 miles at a time and I want something that can roll on the trail well and provide a smooth ride.

Also, I sometimes pull my son in his little trailer, and I was thinking about getting a 25 width tire for the rear so I could run a little less pressure and get a little better riding quality out of it. How much will getting the wider rear tire affect my riding with just myself?