A couple folks have mentioned a 9sp 13-26 cassette. I'm running a 12-25 with Ultegra 9sp triple with 52-39-26. I changed the stock 30 to the 26 to help my 63yr old body up our steep local hills and it's been great and I rarely get into that lowest combo as I've gotten stronger. I tooth lower to 26 might be a slight help but I rarely use the 12 and the 13 makes so much more sense to this recreational rider. Where can I find a 13-26?