I previously had an SRAM equipped Brompton M6 (whose original frame I noticed was sitting in the corner at Phoenix cycles), and now I've got a SA BWR equipped M6.
Possibly with the SRAM hub, but definitely with the Sturmey hub I've always thought that the standard gearing was wrong (for me), 5th gear (low 3rd gear on the hub) was fine on the flat in still conditions, but the slightest headwind or rise and I'd have to change down which knocked off a lot of speed.
Looking for something the other day I came across a Brompton gear calculator so put in the details and got out the numbers. The top 3 rations are 64, 81 and 100 inches. Now teethgrinder of this parish may be happy to cruise around all day on 100 inches, but 81 inches on a very upright bike is a bit too much for me.
So I changed the numbers to look at the -12% option, 56, 71 and 88. 71 inches is about what my fixies have, so last night on went a new chainring, chain and sprockets. So much better, I can happily ride around in 5th, cope with inclines, regain lost speed all without changing down or making my knees hurt. 6th gear is doable in the right conditions on the flat. First is a bit low mind, even with a bag on the front and without trying the front wheel wasn't touching the road until about the 3rd pedal stroke - but I can live with that.
However, now I've got a quandary. While I had the wheel out I found a recently broken drive side spoke (they were all fine 10 days ago), so on the way to work I stopped off a Phoenix Cycles to get some spares, and given the price of single spokes a complete set made much more sense. Except now I've had another look at the wheel and the rim is worn - it's started to go concave by about 1mm.
So now I'm thinking that rather than taking the wheel out, sprockets off and putting one spoke in, it might be better if I went and picked up a new rim tomorrow and just rebuild the wheel. Choices, choices.