Best 9 speed cassette for fast & flat I have a road bike with a 26/11 9 speed SRAM rear cassette. I cycle in Cambridgeshire on a daily basis and it's very flat. I find that I never use the hardest cog, leave the chainring on the biggest cog and generally find that the jump between gears is a little too much.

My chainring is a compact 50/34 110mm.

Sometimes it gets very windy and I'm forced to have to change to the smaller chainring cog - I guess that means I don't want the big cassette cog to be any less than 26 or so. I'm not a fan of changing between my chainring cog much as it kind of changes everything.

Ideally if it exists, I guess a 27/14 (do they exist?) or something similar would suit me better... not sure if 27/15 would cut my top speed down too much though.. I find with my current 28/12 I can get over 30mph without spinning out (with lots of room to play). I never go this fast unless I get an amazingly lucky tailwind :) There's no downhill here either!

Basically I have no experience of different cassettes so any guidance from an experienced cyclist would be of great help. I'd like to avoid buying something stupid.

---- UPDATE ----
In the end I replaced my 9 speed drivetrain with a tiagra 10 speed.. this was fairly involved as I needed quite a few new components: new shifters, cables, derailleur, cassette, also got new chainrings, crank arms, bottom bracket (and pedals as I just couldn't get them off!) One of my reasons for replacing all the old stuff was that it was worn, another was that I recently got a tax rebate!

The 'feel' of this change is apparent and it does seem to help a bit.. however speed wise my new wheels made the biggest difference!
My guess is that if you have 12-28, you might not have a Shimano 9 spd hub. Generally Shimano road clusters top out at 27t. That sounds more campy-like to me. That's the first thing to figure out. Shimano and SRAM clusters are interchangable, Campy are not. 

If you have a shimano hub, it's very easy to build 'custom' cassettes with Shimano 9spd parts. It's just not cheap. If you've got the tools to remove the cassette, you can get an 14-25 

http://www.chainreactioncycles.com/us/en/shimano-tiagra-hg50-9-speed-road-cassette/rp-prod387

and mix and match with your current cassette to get the gears you want. It may be possible to do the same kind of mix/match with campy 9spd cogs, it's just more expensive. You can get 14-28 campy cassettes. 

http://www.universalcycles.com/shopping/product_details.php?id=5047&amp;category=40

If you can find them, junior racing cassettes are a good solution. Junior racers have gear limitations so they tend to have clustered but lower gears. Currently they only seem to be available for 10 speed cassettes, but you can get 16-27
cassettes. 

If you poke around enough on the web, you can find small companies like IRD that will make all kinds of custom cassettes. They aren't cheap though.

http://interlocracing.com/cassettes_steel.html