Thought I'd post this in C&V since both these brands appeal to us C&Vers.
My Mercian is currently shod with Challenge Parigi-Roubaix tires, which are labeled 700x27 but measure a true 29.0-29.5mm. It's the widest tire that can fit the bike, and I'm happy with them. They're comfy and roll fast, but I'm concerned about their tendency to flat. I want to able to ride this bike more frequently on dirt roads, and I haven't flatted yet, but just about every review of this tire indicates it's only a matter of time before they do.
It seems the GB Serf in 29mm is a perfect substitute for the Challenge P-G in terms of size, ride quality and speed, and the reviews back this up. However, missing in a lot of the reviews is their flat resistance. I'm *guessing* they are more flat resistant. Can anyone back this up with personal experience? If they are truly more robust than the Challenges, I'd be willing to shell out the $120 for a pair, but if they're flat prone as well, they're no point in upgrading.
Just for kicks, I'll make it a poll. Keep the Challenge P-Gs or shell out for the GB Serfs.