I got to try the Pacific CarryMe DS this weekend.It is one very nice bike, but looks a little cheap compared to the Bromptons and Dahons that were next to it at the Velo Expodium. The DS bottom bracket is cool; I believe it's a Schlumpf (or a copy) Mountain Speed.

[b]The gear ratio of A-bike/A-bike Plus[/b]:
[url=http://web.archive.org/web/20090502074858/http://www.a-bike.co.uk/store/specification.php]http://www.a-bike.co.uk/store/specification.php[/url]
[b]Gear inches[/b]: 6" x 14 ÷ 8 × 35 ÷ 9 = [b]40.83"[/b]
[b]Metres of development[/b]: 0.15m x π x 14 ÷ 8 × 35 ÷ 9 = [b]3.21m[/b]
[b]Gain Ratio[/b]: 150mm ÷ 2 ÷ 140mm x 14 ÷ 8 × 35 ÷ 9 = [b]3.65[/b]

[b]The gear ratio of A-bike City[/b]:
http://www.facebook.com/photo.php?fbid=167674339920769
[b]Gear inches[/b]: 8" x 14 ÷ 8 × 33 ÷ 11 = [b]42"[/b]
[b]Metres of development[/b]: 0.2m x π x 14 ÷ 8 × 33 ÷ 11 = [b]3.30m[/b]
[b]Gain ratio[/b]: 200mm ÷ 2 ÷ 140mm x 14 ÷ 8 × 33 ÷ 11 = [b]3.75[/b]

[b]The gear ratio of Handybike[/b]:
http://www.handybike.com/uk/technik.html
[b]Gear inches[/b]: 6" x 52 ÷ 7 = [b]44.57"[/b]
[b]Metres of development[/b]: 0.15m x π x 52 ÷ 7 = [b]3.50m[/b]
[b]Gain ratio[/b]: Unable to calculate due to the unknown crank lenth

[b]The gear ratio of Zerobike[/b]:
[url=http://web.archive.org/web/20080715124655/http://www.zerobike.com]http://www.zerobike.com[/url]
[b]Gear inches[/b]: 8" x (34 ÷ 14)² = [b]47.18"[/b]
[b]Metres of development[/b]: 0.2m x π x (34 ÷ 14)² = [b]3.71m[/b]
[b]Gain ratio[/b]: Unable to calculate due to the unknown crank lenth

[b]The gear ratio of CarryMe SD or CarryMe DS in low gear[/b]:
http://www.pacific-cycles.com/product3.asp?cat1=1&cat2=7&pid=11
[b]Gear inches[/b]: 8" x 84 ÷ 14 = [b]48"[/b]
[b]Metres of development[/b]: 0.2m x π x 84 ÷ 14 = [b]3.77m[/b]
[b]Gain ratio[/b]: 200mm ÷ 2 ÷ 160mm x 84 ÷ 14 = [b]3.75[/b]

[b]The gear ratio of CarryMe DS in high gear[/b]:
http://www.pacific-cycles.com/product3.asp?cat1=1&cat2=7&pid=12
[b]Gear inches[/b]: 8" x 84 x 1.65 ÷ 14 = [b]79.2"[/b]
[b]Metres of development[/b]: 0.2m x π x 84 x 1.65 ÷ 14 = [b]6.22m[/b]
[b]Gain ratio[/b]: 200mm ÷ 2 ÷ 160mm x 84 x 1.65 ÷ 14 = [b]6.19[/b]

[b]The gear ratio of CarryAll[/b]:
http://www.pacific-cycles.com/product3.asp?cat1=1&cat2=7&pid=13
[b]Gear inches[/b]: 8" x 64 ÷ 14 = [b]36.57"[/b]
[b]Metres of development[/b]: 0.2m x π x 64 ÷ 14 = [b]2.87m[/b]
[b]Gain ratio[/b]: 200mm ÷ 2 ÷ 160mm x 64 ÷ 14 = [b]2.86[/b]

[b]The gear ratio of Strida 1, 2, 3, 5 & LT[/b]:
http://www.strida.com/en/products/?method=listing&sid=1
[b]Gear inches[/b]: 16" x 100 ÷ 30 = [b]53.33"[/b]
[b]Metres of development[/b]: 1.185m x 100 ÷ 30 = [b]3.95m[/b]
[b]Gain ratio[/b]: 1185mm ÷ π ÷ 2 ÷ 170mm x 100 ÷ 30 = [b]3.70[/b]

[b]The gear ratios of different models of [url=http://en.wikipedia.org/wiki/Mini125]Mini125[/url][/b]:
http://www.bikeforums.net/showpost.php?p=8149749&postcount=13

References:
http://en.wikipedia.org/wiki/Bicycle_gearing#Measuring_gears
http://en.wikipedia.org/wiki/Gear_inches
http://en.wikipedia.org/wiki/Gear_inches#Calculating_metres_of_development
http://www.sheldonbrown.com/gain.html