23 25 or 28mm ties on road bike

[robc02]

I have regularly used Continental GP4000SII in both 28 and 23 mm, as well as other high quality 23mm tyres. The 28mm are noticeably more comfortable and I can't detect any speed loss from them. That doesn't mean there isn't any, but it is lost in the "noise". (In fact, I might even be slightly faster on them - the odd tenth or two of a mile per hour - but it is too small a difference to be confident). The timed rides were over undulating routes of 40 to 55 miles at average speeds around 18 - 19 mph depending on route.