Note: The overall gear ratio of the widest available 7-speed and 8-speed cassettes is the same, created by identical 11T & 34T cogs.
I reviewed the gear inch ranges of the Dahon 7spd and 8 SPD drive trains... Way before I purchased and talked to many in this forum...
The7 SPD gear inch range per the Dahon spec link was 37.2" - 74.2"
The 8 speed range was 32.6 gear inches to 86.6 gear inches...
I did test ride a 7 speed..top gear spun out too soon for my taste...
The 7 SPD's smallest cog was a 13 tooth...the 8 SPD had an 11 tooth...major difference there..
You should be able to look this up on the Dahon site under 'specifications'