My 20″ Dahon Vector X27h preceded my Bromptons & was an easy choice for a folder when most of my bike-time was spent on a carbon frame race bike. It has a great road-bike feel & the specs make it one of the best performance folders you could ever want (well, until it’s superseded via the usual later-model upgrade-cycle?). Funny about the 20″ moniker though; the wheel size is 18″ on all the Dahons (& Terns) that I’ve seen.
To say, “what lets it down…” may give the wrong impression; it’s a great bike – it’s just that Bromptons are so good & show it up in the fold & engineering departments. However, being a performance bike it probably lacks some of the versatility that a good folder needs. My Vector has also had a number of upgrades (sometimes just to “correct” the engineering?) & our lives together have been a learning experience (often frustrating but better for the learning?). The one aspect of the spec that is pretty unique is also the item that is (almost) the “Achilles Heel” – the 27-speed transmission, with 3-speed hub gears & 9-speed rear derailleur. Once sorted & aware of the quirks; no problems?
Without any great detail, here’s some notes about what’s gone on –