Originally Posted by
Gribouille
Hello, do you have any build log for this modifcation ? Would love to see a tutorial for this.
Cheers
Welcome to Bike Forums and Folding Bikes. Glad you came along. How about sharing a little about yourself and your bikes?
The short tutorial would be that I sourced most of the parts from ebay and made them work. However, I can be more detailed to specific questions. My assumption (which could be very wrong) has to do with the SRAM Dual Drive system. Let me begin by describing the original drivetrain.
This Dahon is the Speed 7 model and it was either a 2013 or '14. It came with an inexpensive single crank with a bash guard and a 7 speed Shimano freewheel. IIRC the freewheel was 13-28 and the chainring was 48 or 50.
I was not happy with this gearing for the mostly coastal/beach riding I was doing while on vacation. I changed the freewheel to a mid '90s Sachs Aris 8 speed which was 12-24. I also went to Shimano 105 8 speed barends which I found shifted better in friction mode. However, the cheap permanent chainring somehow became bent in the suitcase, so I upgraded to an early '90s Shimano 105 double crankset (53-42) and added a Shimano FD and Litespeed mounting bracket. Thus the Speed 7 became a Speed 16.
This past Fall, while browsing ebay for a replacement part on the Dual Drive system I have on a Cannondale hybrid, I spotted the 20" (406mm) Dual Drive wheel. I was intrigued and the price was very reasonable since it was missing a few parts and came with no shifters. Digging in the archives I found that Dahon had offered this option in the past on certain models for a 24 speed system (8 speed cassette combined with the 3 speed IGH).
I knew the freehub on the Dual Drive can handle a 9 speed cassette (and probably a 10 speed). So combined with the double crankset and the IGH I have a 2X3X9 system, or a 54 speed Dahon (BTW I've ad my Cannondale set up as an 81 speed). This provides way more gearing options than ever needed--- but provides lots of flexibility, especially when coming to a sudden stop and there was not time to shift to a lower gear. The Dual Drive IGH lets you downshift while stopped.
Hope this is helpful. Please feel free to ask any ore questions and I'll do my best to answer.