Thanks, fastest I've gone is 47mph, thats downhill and not pedalling as I just spin in the top gear at that speed. And they're 700x23mm, will be replacing them with Continentals soon.
Oh right. Not sure how fast I can get to on my Viking as I have no computer. It's got 32c's on it and is pretty sluggish compared to thinner tyres. Are you getting GP4000 tyres? I'm getting them for my Kinesis as I got the frame in the end.