Saturday, September 28, 2019

Bike Friday HaD: Final Assembly and Bike Dimensions

Finally, with all the components of the Bike Friday Haul-A-Day in place, I can complete the assembly and show you the complete bike! I don't have many pictures of the bike assembly process as the hands are busy fixing and adjusting the components.

For more details on the components of this bike, check out this page which has the links to all the previous posts about this Bike Friday Haul-A-Day cargo bike.

One of the decisions I had to make was to select the correct hole on the frame, to fix the length of the bike. This is one of the adjustable areas on the bike where the top tube length can be adjusted, which changes the handlebar reach, so that it can fit riders of different height.

Since this is a flat handlebar setup, I wanted to maintain the same geometry as the Dahon MuEX, which also has a flat handlebar setup that I am comfortable with. In this case, the measurement that I can use is the distance from the bottom bracket to the front axle.

Distance from bottom bracket to the front axle on the Dahon MuEX is about 620 mm.

By using the middle hole out of the five, I found that the distance between the bottom bracket and the front axle is almost 620 mm, which is same as the Dahon MuEX.

Later, the actual handlebar reach can be adjusted by using a different stem length, but I think it should be OK. Once this top tube distance is fixed, other bike geometry numbers will also be fixed. Also, the lengths of the Di2 wires and hydraulic hoses can be determined only after the frame length is fixed and the handlebar is installed.

The chain stay length (distance between bottom bracket and rear axle) is 690 mm, which is a lot longer than the usual 400-430 mm found on other bikes. Of course, this also means a longer chain is needed, which is why I had to get two chains and join them together.

Overall wheelbase (front axle to rear axle distance) is 1310 mm, which is also much longer than the usual 1000 mm found on a road bike. Note that this wheelbase is a result of selecting the middle hole on the frame. By choosing the extreme holes, I estimate the wheelbase range to be 1310 +/- 50 mm.

Overall length (front tire to rear frame) is 1870 mm, which is surprisingly not that long. My Fabike C3 commuting bike has an overall length of about 1800 mm, so this cargo bike is only longer by about 70 mm. This is due to the smaller 20" wheels of this Haul-A-Day, which enables a long wheelbase without extending the overall length by too much. Another advantage of using smaller wheels for cargo bikes.

One of the main concerns when building this cargo bike, is whether there will be sufficient ground and tire clearance with the rear derailleur. As a relatively large 11-40T cassette is used on these 20" wheels, there might not be enough clearance when shifting to the lowest gear (largest sprocket).

Cage position of the Deore XT Di2 rear derailleur, when shifted to the largest 40T sprocket.

Ground clearance should be OK, but it does look very close to the tire.

There will be sufficient ground clearance with the chain, unless you choose to ride UP a curb...

Not much tire clearance here! About 2 mm of clearance only. Luckily I chose the narrower Schwalbe Marathon tires with a width of 1.5".

At the other extreme condition, with the chain on the smallest 11T sprocket. The chain could have been slightly longer, but I think it should be fine.

Overall look at the drivetrain. See how long the chain is!

Ascent Bikes front single crankset, with narrow wide teeth on the 44T chain ring. I like this crankset as it is simple and affordable, and already comes with a narrow wide chain ring.

A narrow wide chain ring is highly recommended for a front single drivetrain, to prevent chain drop when changing gears or traveling over bumpy roads. The long chain stay is advantageous in this case, as it reduces the offset angle between the chain and the chain ring teeth. Together with the one-way clutch function of the Deore XT rear derailleur, it should prevent chain drop and chain slap.

With the trusty PD-A530 pedals (SPD/Flat) installed.

Handlebar set up! Looks wide, but it is just 600 mm across.

With the 100 mm PRO PLT stem installed, and the Di2 Digital Display on the handlebar.

Very comfortable Ergon GS3 Grips installed! XTR Di2 Firebolt shifter is used to activate the Di2 rear derailleur.

Making the cabling neat with carefully measured cable lengths and some cable wrap.

View of the full bike! Bare bones set up, inclusive of the rear wrap-around bars for kids.

Another view of the full bike, ready to go for a test ride!

The full list of components used to build this Bike Friday Haul-A-Day cargo bike. There are some big discrepancies between the listed weight and actual weight of the Bike Friday parts.

I decided not to install the foot rests at this point in time, as my kid can't reach the foot rest anyway. It is an additional 1.4 kg, plus it adds to the bike width which is not ideal. It comes as part of the "Younger Riders" package by Bike Friday.

Estimated weight was about 16.88 kg (including pedals), but actual weight is 18.92 kg (including pedals. About 2 kg more than the estimated weight. The difference mainly came from the frame weight, but I did not dismantle it completely and so I am not sure which are the components that contributed to the differences.

To have a cargo bike that weighs less than 20 kg is actually pretty good. Although it weighs twice as much as my Fabike C3 commuting bike, it is expected since this cargo bike has a steel frame, plus lots of additional material and parts, such as the rear rack, wrap-around bars, side bags, seat mast, heavy duty wheels, etc.

Bike is out in the wild! With the large side bags that can carry lots of things.

The bike is eye-catching everywhere it goes, with the unusual frame and lovely Robin's Egg frame colour.

Kick scooter plus helmet fits into one side bag! To be deployed at the park when necessary.

When the bike is positioned vertically during storage or entering the elevator, the ends of the rear frame will touch the ground. Temporarily, I used some black tape to protect the frame, while I come up with some ideas for a long term permanent solution.

Thick layers of black tape applied at the ends of the rear frame, to prevent damage to the frame.

This cargo bike can be stored vertically, which saves A LOT of space, as it only takes up as much floor space as a folded folding bike. How many wheels can you spot in this picture?

This cargo bike is unlike any other bikes which I have built or tested, as it is totally designed for another purpose. In my case, it is to bring my kid to the park or school, while allowing some items to be carried along easily. In a way, it is a weekend bike, which will be used rather sparingly as we will not be going to the park everyday.

There are many advantages that this Bike Friday Haul-A-Day has over other cargo bikes. Here are just a few:
1) Can be stored vertically to save space. This is a critical factor that led me to choose this cargo bike.
2) Small 20" wheels for lower centre of gravity and better load balancing.
3) Child friendly accessories such as the wrap-around bar, the seat cushion, side bags, etc.
4) Adjustable frame size, so that I can set it to exactly what I need.
5) Disc brake compatible, for safe and easy braking function.

As for the downsides, there is only a few that I can think of. Compared to other cargo bikes, these are not downsides, but compared to normal bikes, it is a disadvantage.
1) Long overall length makes it tricky and more troublesome to transport in an elevator, compared to a normal bike. It will not matter if you live on the ground floor.
2) Heavier weight compared to normal bikes, but it is actually lightweight compared to most other cargo bikes.

Tuesday, September 17, 2019

Bike Friday HaD: Di2 Battery Placement and Wiring Layout

For a cargo bike such as this Bike Friday Haul-A-Day, the frame will always be longer than a standard bike. As such, the cable housing that runs from the handlebar to the derailleurs or the brake calipers will be longer than usual.

A longer cable housing always means more friction, which can cause poor shifting performance or decrease the brake performance. Using high quality inner cables or outer casings can help, but it will always be poorer compared to an equivalent setup on a standard bike due to the extra length.

On this bike, I am using hydraulic disc brakes, which means that the hydraulic brake hose will need to be longer than usual. As already described in detail in a previous post, an extra long hose is needed to reach the rear brake caliper from the handlebars. For this case, a longer hose may result in slightly spongier brake feeling on the rear brake, but it is inevitable.

As for the shifting performance, since I am only using a rear derailleur for a 1x11 speed setup, I do not need to consider the front shifter or front derailleur. However, in this case I do have an option to optimize the rear shifting performance.

Instead of using a mechanical shifter and rear derailleur, I decided to use electronic shifting instead, as already used on many of my other bikes, such as the Dahon MuEX, Dahon MuSP, and others. This eliminates the inner cable friction caused by a longer outer casing, and ensures that the shifting performance will always be good as it is not affected by friction. As shown in a previous post, I will be using a Deore XT Di2 rear derailleur on this bike.

The handlebar setup will be almost the same as on the Dahon MuEX, with an XTR Di2 Firebolt shifter (SW-M9050) and a Deore XT Di2 Display (SC-MT800). This electronic shifting setup will be powered by an external Di2 battery, since there is nowhere on this frame to stow an internal Di2 battery, unlike on my other bikes such as the Fabike C3 or the Canyon Endurace. The challenging part is thus to determine a good place to mount the external Di2 battery.

Testing out all the Di2 components to ensure that they are updated and work correctly, before installation onto the bike.

Initial plan was to design and 3D print a mount for the battery, and mount it behind the seat tube, similar to the Dahon MuEX and Dahon MuSP. From my experience, this location is neatly hidden by the chain rings, and is easily accessible to remove the battery for charging.

However, with the actual frame, I found that the front derailleur mount (top) and the cable stopper (below) blocks the placement of the battery mount.

As there is not enough space behind the seat tube to mount the external Di2 battery, I had to look for alternative locations for mounting the battery. The basic wiring concept will remain the same, just that wire lengths need to be adjusted to account for the different distances between the Di2 components.

One alternative location is below the "bottle cage mount", which is located in between the seat tube and the rear section of the frame. Refer to this post for more pictures.

Another alternative is to secure it under the metal plate, at the rear of the frame. This area is unused anyway and can be accessed relatively easily.

After changing to a long battery mount, it can be secured easily to the bottom of the metal plate, using the existing holes.

This new battery location seems good, but I will need to get new Di2 wire lengths in order to connect up everything. The main issue here is the long distance between the handlebar (Di2 Display) and the Junction B, which will be located beside the Di2 battery. The longest Di2 wire (1600 mm) cannot cover this distance, therefore I will need to join two Di2 wires together to connect them up.

Last time, a Junction B can be used to join Di2 wires together to extend them, but there will be two unused ports on the Junction B. Recently, a connector was created to allow the joining of two Di2 wires, while maintaining a slim joint.

EW-JC200, which is basically just a connector to join two Di2 wires. Despite having no active electronics inside, it still costs SGD 30!

Junction B attached to the underside of the metal plate, with some strong mounting tape. As it is not heavy, this will be sufficient.

Di2 wiring runs alongside the rear brake hydraulic hose, along the non-driveside chain stay to the rear of the frame, before routing upwards to the metal plate where Junction B is located.

Final Di2 wiring layout on the Bike Friday Haul-A-Day. As you can see, a total wire length of 1900 mm is needed to connect Junction A (Di2 Display) to Junction B.

With the Di2 wiring installed, it means that the bike is almost completed!