Not for Mountie my commuter bike, but for Trekkie my road bike. The stock cassette – 12-25, 9 speed was too narrow for the local terrain – lots of short, steep climbs, and a lower level of fitness from less time on the road. I swapped out to a 13-30 9 speed Shimano cassette and am now much, much happier. Harris Cyclery builds this custom cassette and they were terrific to deal with. I had the parts shipped to my local store – I bought their recommended chain – and they made the change. I’m training for a 135 mile in late June, just me and a friend doing a ride we wanted to do for years, and this cassette will help. To be honest, I think the biggest benefit is psychological, knowing that I have some gears in reserve relaxes my mind and gives me the confidence that I can get up and over whatever is in front.