Thursday, June 1, 2017

Java Freccia Carbon Mini Velo: Part 4 - Preparing for Assembly

With the frame and fork weighed, and the geometry comparison completed, it is time to prepare the frame for component assembly! All the components will be transplanted from the Wheelsport mini velo wherever possible, as this Java mini velo will replace the Wheelsport mini velo.

First, let's install the headset. This is easy as there is no need to press fit any headset cups into the frame.

Placing the lower headset bearing onto the fork. The crown race is already molded into the bottom of the steerer tube.

Placing the compression ring on top of the upper headset bearings

Placing the cover on top of the headset compression ring. The carbon spacer will then press onto this cover.

The carbon spacer was purchased separately, and I had to estimate the length required. 120mm is too long for this steerer tube, so some cutting is required.

Inserting the compression plug from the top cap into the steerer tube, in order to judge the length of the carbon spacer that needs to be cut.

As I plan to use the 80mm Controltech stem which is originally used on the Avanti Inc 3 (it turned out to be too long for that bike), I measured the stem height to determine the amount that needs to be cut.

Available space between top cap and 120mm spacer: 13mm
Space required for Controltech stem: 40mm
Space required for 5mm spacer on top of stem: 3-5mm

Therefore, I will require about 43mm of clearance between the carbon spacer and the top cap, so that I can fit the stem (with 40mm height) and spacer (5mm height), while ensuring that the spacer protrudes from the steerer tube by a few millimeters.

This means that I will need to cut about 30mm off the carbon spacer, trimming it from 120mm to approximately 90mm.

Using a carbon saw (similar to how I cut the FSA SL-K seatpost), instead of using the pipe cutter (when I cut the carbon spacer for the Wheelsport mini velo), I was able to obtain a relatively good and flat cut.

Final height between the 90mm carbon spacer and the top cap is about 43mm, which is perfect. If anyone else intends to build a bike with this frameset, a 90mm carbon spacer will be just right.

Controltech stem installed!

As pointed out earlier, this frame uses a press fit bottom bracket, not a traditional threaded bottom bracket. I would have preferred a threaded bottom bracket, as it makes it easy to install or remove the bottom bracket. However, the advantage of press fit bottom bracket is lighter weight, as there is no need to have metal threads on both the frame and the bottom bracket itself.

I was not sure which press fit bottom bracket to use, therefore I had to do some research to see what bottom bracket will fit this frame. The frame shell width is about 86mm, while the internal diameter is about 40.9mm.

Specifications for Shimano press fit road bottom bracket

With this confirmation, this frame will accept a Shimano press fit road bottom bracket.

Surface of the press fit contact area looks rough, but it is actually quite smooth to the touch, which is ideal. Will use some fine grade sandpaper to prepare the surface before installing the bottom bracket.

The main issue with press fit bottom brackets is creaking sound during usage, which is almost always due to poor fitting between the bottom bracket cups and the frame. It can be due to poor press fitting tolerances, or just failure to prepare the surfaces properly. Some people prefer to use loctite to prevent any movement that will cause creaking, but this makes it super difficult to remove. I prefer the other school of thought, which is to apply grease at the contact areas, so that in case it does move, it will not cause creaking sounds.

While prepping the frame for assembly, I also studied the cable routing for this frame. This frame is designed for internal routing, which keeps the exterior of the frame clean and tidy. However, this also makes it more troublesome to install or service the cabling.

Cable stoppers on the frame, which clips into the hole on the frame via a smart snap fit design.

Snap fit design of the cable stopper makes it easy to remove the stoppers for easy cable installation.

Upon closer inspection, I found that there are two different stopper designs. The first is for shifter cables, where the outer cap will be stopped by the cable stopper. The second is for the brake cables, where the outer casing will run straight through. The difference is a step inside the cable stopper.

Cable stopper for shifter outer casing, which holds the outer cap and allows only the inner cable to pass through. The inner cable will then be exposed while running internally through the frame.

Cable stopper for brake outer casing, which has a through hole that allows the whole brake outer casing to pass through, with no exposed inner cable.

Testing the cable guide under the bottom bracket, to determine how to route the cables through the frame. The route shown here is for the rear derailleur inner cable.

This bike will have a 1x11 speed drivetrain, similar to that on the Wheelsport Fantasy mini velo. Therefore, I only have to be concerned with the routing of the rear derailleur inner cable and also the rear brake cable.

I was not too happy with the exposed inner cable running under the bottom bracket, as it will collect too much dirt and affect shifting accuracy. In order to prevent this, I decided to run a plastic cable liner to protect the inner cable from dirt.

The cable liner is the same as the one found inside the shifter outer casing, and the easiest way to get it is to cut open the shifter outer casing and extract the plastic liner from the inside. Another advantage of putting this plastic liner is to make it easier to install the inner cable later on.

Splitting the shifter outer casing to obtain the plastic liner

Running the plastic liner from the front of the frame...

...under the bottom bracket...

...and out from the right side chain stay.

During the installation of the inner cable, it will be easier to thread the inner cable through the whole frame, since the plastic liner is already there to guide it through. After that, the plastic liner will need to be trimmed so that it does not touch the outer cap on the outer casing at either end. This liner is supposed to "float" on the exposed section of the inner cable which is inside the frame.

Next, the wheelset, crankset, rear derailleur and chain was transferred over from the Wheelsport mini velo. The next step would be to install the rest of the components!

Java Freccia mini velo half assembled. To be continued!

6 comments:

  1. Interested to know how this one rides. Have been eyeing this frame for awhile. Not sure how is the stiffness for say semi aggressive road riding. But nice job! :)

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    Replies
    1. This bike rides really well. Feels like a road bike.

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  2. Where did you buy the carbon spacer tube?

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    Replies
    1. I got it from this link.
      https://world.taobao.com/item/38069798857.htm?fromSite=main&_ezgpid=20000005843781
      If you are intending to use it for this same frame, 90mm will be just nice without needing to cut.

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  3. I have a question regarding type of grease that is safe for carbon fiber frame? thanks in advance.

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    Replies
    1. I think the commonly used grease for bicycle components is safe for carbon frames. Don't think it is a problem.

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