Originally Posted by
PeteHski
2 mph slower average is a massive difference. Certainly not attributable to 3 lb weight or equivalent 25 vs 32 mm tyres. They certainly wouldn't be racing Paris-Roubaix on 32 mm tyres if they were 2 mph average slower on pavement!
I don't disagree that weight alone would not explain the difference. The only bikes in my stable that can fit wider tires are my gravel bikes (albeit, they are similar to regular road geometry apart from the slightly longer chainstays), so I'm not comparing the same performance road bike with wide vs skinny tires. But I suppose that is the unanswered question in my mind: how would my nice road bikes ride with slightly wider tires (though several have noted here that they would be just as fast and nice riding even if with a slight weight penalty).