On my UST rims, I have been running Hutch Spider 2.1s both front and rear. It's a great tire, but on my other, non-UST rims, I have been using a Kenda 2.1 r and another kenda 2.3 up front. I now much prefer what is usually a larger volume tire with bigger knobs up front and want to try a 2.25 or 2.3 up front on my UST rims (819). I have tried BG up front but just can't get it to hold air so am sticking with UST tires on the UST rims. Seriously considering the Spider 2.3 just because I love the 2.1. Also considering Geax Sturdy and Nokian NBX. Is anyone running the Spider 2.1 r and 2.3 f combo - if so how does it compare to 2.1 f? What are your recommendations for dry conditions with very varied N.Cal terrain?