I find I never use the 32 and 28 cogs at the back (maybe I don't do enough hill work) so am considering a road cassette 14-25 – 14.15.16.17.18.19.21.23.25. Single speed usually ride around 32 to (16/17/18) so I figure a 14-25 will do fine.

Anybody done this?

no reason not to

i'm using an 11-26 cassette and it works fine for me

Depends where you live i guess, but i've noticed of recent since moving to the south i've never needed anything lower than 32:32. So i was thinking of going for an 28-11/27-12 ultegra roadie cassette to save weight and have the closer ratios.

I run a 12-27 and planning a change to 10 speed 11-28 for next season. Works well, drops weight and keeps a tighter cadence.

I've just put on a 12-25 in place of my 11-32.

I run an Ultegra during the summer.

I'm tempted to go for a dura ace 9sp at 160g!

tbh i would be tempted to stick the 32-11 back on for winter, i find higher cadence aids traction if its muddy.

run a 11-28 on my race bike, no need for anything else

which 11-28 do you run though? SLX do an 11-28 or is it a roadie one?

I used to do it, but got annoyed with shifting on the front more often, would rather have a wider cassette and not on the rings so much myself, but there's no reason not to do it. In fact it saves more weight than going 2×9.

which 11-28 do you run though? SLX do an 11-28 or is it a roadie one?

slx version. Still lighter than an xtr 11-32

run a 11-28 on my race bike, no need for anything else

Do you not think it's quicker to not have to drop down on the front though? If you lose 2 seconds for every shift down/up, it adds up seriously quickly! I much prefer a 2×9 with a wide ratio cassette so you can just stay in the big ring for much longer, may not save as much weight, but is faster IMO.

i have to agree with nick, in terms of speed and "shiftability" it's much easier to change down the cassette than keep fannying about going from granny ring to middle over and over,

weight VS rideability

Do you not think it's quicker to not have to drop down on the front though? If you lose 2 seconds for every shift down/up, it adds up seriously quickly! I much prefer a 2×9 with a wide ratio cassette so you can just stay in the big ring for much longer, may not save as much weight, but is faster IMO.

This aint f1 we're talking about.
For a start, you dont lose 2 secs on any shift.
secondly. Before you hit a climb, descent etc you should be in the right gear, so for instance, if i was to come to a climb i would know if i need to be in the middle or top chainring.
I only run a 3×9 because finances have prevented me getting a 2 x 9 or 2 x 10 set up.
using a 3×9 set up allows me though to hit the inner chainring for fatigue or general spinning reasons. But if i;m gonna use it i'l know prior to the climb if i need to be in it.
i also like my 44t top chainring which i use alot. Fannying about going between chainrings instead of cassette ratio's may lose fractions of time but if you feel its costing you alot of time over a race then you need to seriously think about your riding style and also your managing or thinking about situations during your ride.
I can honestly say i've never finished a race thinking my shifting has cost me places, chainsuck maybe but not the actual process of shifting

for the past year i've used a Dura ace 12-25 9 speed cassette.
it's been great and it's worn far batter than the XTR I used before.