Journey of the Boardwalk: Part 13 - Dahon Boardwalk TT

Disclaimer: Major upgrade poison ahead! Read at your own risk!

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Ever looked at the Dahon Speed Pro TT, Vector X27 or the Verge X30 and wish you had the bullhorn handlebars? Now you can! With the correct components and some mechanic skills, you can install bullhorns on almost every Dahon folding bike. The bike will still be foldable, using the folding method described in an earlier post.

Advantages of bullhorn handlebars over standard flat bars:
1) More hand positions for better comfort and versatility, especially over longer rides.
2) Longer reach is possible, especially for people with longer upper bodies.
3) More aerodynamic when certain hand positions are used.
4) Brake and shift using the same levers, and reap the ergonomic benefits of the Shimano Total Integration (STI) levers.
5) More natural hand position (palms facing each other) when holding the sides of the bullhorn.

With all these in mind, I set about gathering the components that I needed for the upgrade. In fact it took me more than a month to gather all these parts. Needed to do some research and ask around too for advice. No hurry to do so since I can ride my bike in the meantime anyway.

Components required:
1) Shimano Tiagra 9 Speed STI Levers
2) Shimano 105 RD
3) Kinetix Pro TT bullhorn, clamp size 25.4mm
4) Inner cables and cable housings - LONG ones for the rear brake and rear derailleur
5) Travel Agents by Problem Solvers
6) Tektro Cyclocross brake levers
7) Lots of cable ferrules for covering the cable housing ends

The hardest component to find were the STI levers, it is difficult to find 9 speed ones nowadays. 105 and above level are all 10 speed already. Finally found a pair of second hand Tiagra levers from Togoparts after some time! Taken off a new bike so they are in great condition.


Previously I was using the SRAM X9 shifters with the X9 rear derailleur. Since I will be switching to Shimano STI levers, I will need a compatible Shimano RD. Once again Togoparts to the rescue! Second hand Shimano 105 RD, from the older 5600 series. No problem, black colour can already haha.

Most of the time, the STI levers are paired with caliper brakes, so that the cable pull when braking is compatible. However, I cannot mount caliper brakes on my Boardwalk, as there are no proper caliper brake mounts and also because the caliper brakes will intefere with the fenders. Caliper brakes are possible! Check out the next part of the series here.

In order to overcome this incompatible cable pull issue, I got these Travel Agents from a company called Problem Solvers. What these things do is to alter the pull ratio of the cable, such that the STI levers pull enough brake cable to activate the V-brakes properly. Without them, the V-brakes will feel very spongy and the brake pads will need to be very close to the rims.

To further complicate the upgrade, I decided to add cyclocross brake levers! (No challenge if the upgrade is too simple! LOL) These brake levers are mounted near the middle of the handlebars, and goes between the main STI levers and the brake calipers. They allow braking even when holding the middle of the bullhorns.

First step is to remove all the components on the handlebar, so that I can swap the handlebar! Not easy because I will also need to loosen all the cables and pull out all the cable housings. I cannot reuse the cable housings or cables because they will be too short to route the cables on the bullhorn handlebars.


After this, I needed to open up the chain so that I can remove the current X9 RD. On the SRAM chain that I am using, there is a Powerlink that can be opened up by hand. However, I found it difficult to open by hand most of the time, because it is quite tight and also because I have to work against the chain tension.

Got the KMC Missing Link Chain Pliers and a X-Tools Chain Connector Aid from CRC.

Hook the 2 ends of the chain connector aid around 2 chain links, such that there is no chain tension across the Powerlink. Squeeze the side plates of the Powerlink together (not shown), and use the pliers to push the 2 ends of the Powerlink together.

With the chain pliers, it is very easy to open the Powerlink! Also, the chain connector aid helps to remove the chain tension before opening the link, and holds the chain for you after opening the link! Simple but really useful tools, saves you from sore fingers and dirty hands.

Time to install the new components! See the new bullhorn, STI levers and Cyclocross brake levers! The gold coloured stem is no longer required to extend the reach.

Running the brake cable housing out from the STI levers is not easy, as the cable housing needs to come out at an angle, and then turn sharply to run along the handlebar. This causes more friction for the inner cable. A short section of housing is laid from the STI levers to the cyclocross brake levers, and then a longer housing all the way to the brake calipers. The inner brake cable runs all the way through everything to the brake calipers.

The inner brake cable first loops around the smaller circle, then around the larger circle. This results in the short pull of the STI levers being converted into a longer pull suitable for the V-brakes.

Setting up the shifter cable is much more straight forward, coming out the side of the STI levers and going to the RD.

Before I wrapped the bar tape, I went for a test ride around the neighbourhood, to finalise the positions and angles of the levers. This has to be done before the bar tape is wrapped, else adjustments would be almost impossible.

Wrapping the bar tape also takes quite a bit of skill. Not just anyhow wrap in any direction you like, you actually need to wrap it properly if you want it to last. Check out the youtube link here.

Note the interesting rotating bell on the left bar end, originally from Bike Friday!

Managed to fit my two front lights and cyclecomputer on the bullhorn!

So far have not had any problems with the bullhorn bars. Initially I was worried that the clamp in the middle might not be able to hold the bullhorn properly, allowing it to rotate if I placed weight on the handlebars. But it has been rock solid so far, no slippage at all.

Lastly, a picture to wrap up this wonderful upgrade!

Will be discussing the hand positions possible on the bullhorn handlebars in a future post. Stay connected and check back often!