Saturday, June 17, 2017

Java Freccia Carbon Mini Velo: Part 6 - Almost Completed

In Part 4 of this bike project, I showed that the drivetrain of the bike was already installed. Prior to that, I had to first install the press fit bottom bracket into the frame, before the crankset can be installed.

I have never installed a press fit BB before, so I had to do some research to make sure I do it properly. Also, I have heard of some cases of press fit BB causing creaking sounds during pedaling. Therefore, it was even more important that I do the installation properly to avoid any creaking later on.

As already checked previously, this frame accepts a Shimano type press fit BB. To ensure good performance and low weight, I chose the Dura-Ace grade press fit bottom bracket. Although it is not the smoothest bottom bracket around, the sealing should be good, while it is also relatively cheap and lightweight.

Dura-Ace grade press fit bottom bracket, SM-BB92

Plain looking bottom bracket, with the two press fit diameters at both sides

Press fit bottom bracket cups are made of engineering plastic, PA+GF for strength while also being lightweight

Press fit BB weighs only 55 grams, which is lighter than threaded type BB

Using the proper press fit tool for pressing the bottom bracket cups into the frame. It is very simple, basically a threaded rod with correctly sized plates at both ends to push in the cups.

Done! Greased the contacting surfaces and managed to press in the cups easily and fully.

Installing the press fit bottom bracket was actually quite easy. The resistance felt just right, while the cups were able to enter fully until they were flat against the frame. Hopefully there will be no creaking sound when I ride the bike later on.

After the press fit bottom bracket was installed, the Dura-Ace 9000 crankset was then installed without any issue.

With the drivetrain and brakes installed, the next thing to install would be the controls of the bike, which is the handlebar. Since the handlebar and shifters will be the same as that on the Wheelsport mini velo, I can transplant the whole handlebar setup over without removing the shifters.

The shifter inner cable will be changed, since the old one is already worn out and is also a bit too short. The brake inner cables can be reused. However, all the outer casing will need to be changed as the cable entry point for the shifter cables into the frame is different, while the brake cable routing has been changed from semi outer casing (with external cable stoppers) to full outer casing.

In this case, there is no choice but to remove the bar tape to redo the outer casing coming out from the shifters. No problem, since the bar tape is due for replacement anyway.

Handlebar setup shown as removed from the Wheelsport mini velo, before installing new inner cables and outer casings.

After much work, the handlebar setup is completed! New cabling all done up nicely.

80mm Controltech stem matches nicely with the colours on the FSA K-Force carbon handlebar

Rear shifter cable enters the frame at the downtube for neat internal routing

Rear brake cable enters the top tube from the front, and exits at the rear. Clean internal routing for this frame.

Using the same lightweight Selle Italia SLR Kit Carbonio Flow saddle on the new aero seatpost

Front single drivetrain for this bike. Look at the massive bottom bracket junction for stiffness!


Left side view. Since the bottom bracket bearings are fitted within the frame, this frame can be wider than an equivalent frame with an external threaded bottom bracket.

Using a custom tool to center the handlebar with the front wheel. The idea is to place the jig on the stem and handlebar, while a laser pointer will indicate the centreline of the handlebar, which is where the front tire should be.

Once done, just line up the front wheel with the laser pointer and the handlebar should be perpendicular to the front wheel.

During this alignment, I found that there are a few issues that can affect the accuracy of this laser guided handlebar alignment jig.

1) The placement of the laser pointer within the jig itself will affect the accuracy. If the laser pointer is tilted just a couple of degrees off, it will not be accurate anymore.
2) The laser beam may not exit the laser pointer exactly straight. This can be remedied by rotating the laser manually during calibration.
3) Distance from handlebar to front tire can affect the accuracy, especially if the laser is tilted to one side slightly.

In my case, the jig is for reference only. Final alignment is still based visually and my feeling during riding.

This bike is almost completed! In the next post, the full bike build will be shown, along with the bike weight (it is really lightweight!) and the component specifications.

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