But my hands are itchy after not upgrading a bike for some time, and the solution is to find another bike to upgrade! I technically have 4 bikes under my stable, with my own Dahon Boardwalk X20-R and Flamingo London S7R, and Bernice's Dahon Vitesse P18-TT and Pacific Cycles Carry Me.
Coincidentally, the Vitesse has been found to be lacking in proper gear ratios at the low end of the gear range. This is due to the custom 9 speed cassette that I previously assembled. You can check out this link for more info on the custom cassette.
12-28T 9 speed cassette, as previously seen on the Boardwalk
This 9 speed cassette has sprockets sizes of 12-13-14-15-16-17-19-23-28. The advantage of this combination is that it has a close spread of high gear ratios (12-17T) for comfortable cruising on flat roads, but also has a low 28T sprocket for those "friendly" slopes.
However, the disadvantage is that the jumps between the lower gears are quite large, as the sprocket size changes quite a lot from 19-23T and 23-28T. This can be a problem when climbing slopes, as the 23T sprocket is too hard, but when changing down to 28T, the difference is too great, and the pedaling momentum is lost.
To solve this issue, the best way is to have one more speed between the 23T and 28T sprocket. But I cannot do that on a 9 speed cassette without sacrificing a sprocket from the higher gear range (12-17T). The solution is to upgrade to 10 speeds!
A lot of people ask why do we want so many speeds? My answer is, it gives you more gear ratios which makes your pedaling more efficient and comfortable. It may not necessarily make you go faster, but you will have more gears to choose from and you will be more likely to find a gear that you can pedal on at a comfortable cadence.
Working from the previous iteration of the Dahon Vitesse P18-TT, the "ingredients" that I need to convert the bike into a 2X10 speed bike are listed as below:
Components needed to upgrade the Vitesse from 18 speeds to 20 speeds:
1) 10 speed road cassette
2) 2x10 speed road shifter
3) 10 speed road front derailleur (FD), double
4) 10 speed road chain
1) KMC MissingLink for 10 speed chains
Shimano Tiagra 4600 12-30T 10 speed cassette.
Shimano Tiagra 4600 2x10 speed road shifters
Why choose this? Instead of the higher end road shifters with internal shifter cable routing, I chose these shifters because of the external shifter cable routing. This is better for bullhorn bars to avoid excessive friction in the shifter cables.
Shimano 105 5700 double front derailleur
Why choose this? Because it matches the rear derailleur and crankset!
Shimano 10 speed chain
KMC Reusable MissingLink for Shimano 10 speed chains
Rear hub with dirty grease. Still not too bad as it was last serviced at the beginning of this year.
Pawls on the freehub body
A clean ratchet! I just took some toilet paper and wiped away the old grease.
Similarly, the pawls and other parts are also cleaned.
As it says on the cover, you need special freehub grease. It is much lighter than normal grease, but more viscous than oil.
Generously coating the ratchet and pawls with freehub grease
After greasing the internals of the freehub mechanism, the freehub runs smoother and much more quietly. The freehub clicking sound will slowly return to its normal levels as the grease is displaced during normal usage.
Back to the Vitesse upgrade!
Sparkling new 10 speed cassette!
Go on, count it. You know you want to.
Tiagra 10 speed road shifters. Great shifters at an affordable price.
New Shimano 105 5700 FD with the older series Shimano 105 5600 53/39T crankset
Shimano 105 5600 series RD
I love the gleaming look of a clean drivetrain!
New bar tape in Bianchi Green! Definitely eye-catching.
Overall view of the Dahon Vitesse X20-TT
I have brought the bike out for a few test rides, and it rides awesomely well! In fact, sometimes I feel that it rides better than my own Boardwalk. With the new 12-30T cassette, the gear range is now 26"-88". Great for climbing, ready to tackle any slopes! The shifting is also buttery smooth, you got to try it to believe it. Personally, I feel that the shifting is at the Dura-Ace level, smooth, light and precise, especially for the front shifting.
It was a fun and great upgrade. Definitely worth the time, money and effort spent!