Wider tires (25vs 28) for Alex at400 on '06 Specialized Roubaix
When I replace the tire(s) on my Specialized Roubaix I'd like to get something wider than the current 23s. How should I measure to see if 28s will fit instead of 25s? Currently everything is original , Alex at400 rims, base model '06 Roubaix I believe (just bought used.)