Saturday, August 20, 2016

Avanti Inc 3: DIY Steering Stabilizer

Do you ride a bike that has a heavy front? By heavy front I mean that when the bicycle is parked, the handlebar tends to tilt to the side, and over-rotate. This causes the whole front wheel to flip to the side, and if the front of the bicycle is heavy, the whole bike will fall over, even if it is resting on a kickstand or resting against the wall.

For most road bikes, they can be supported easily against a wall or on the kerb using the pedals, as they are lightweight. Mountain bikes are usually placed with the bar end against the wall, or just laid down on its side on the ground. Other bikes may have kickstands to hold the bike up when parked.

In my case, I have some problem with parking the Avanti Inc 3 when outside. As there is no kickstand, I will rest the bar end of the Ergon GP3 grips against the wall when parked. However, the bike will sometimes roll forward or backwards due to a slight incline of the ground. This causes the handlebar to rotate and the whole bike will fall over.

When there is no wall to lean against, I will rest the bike against my body when stopping for a short while. Even then, the heavy front end will rotate and cause the bike to fall over easily. This is due to the wide handlebar and the many accessories on the handlebar.

To solve this issue, I decided to get a steering stabilizer to prevent over-rotation of the handlebar. It looks like a very simple device, with just a spring to prevent the fork from rotating too much to either side. After failing to get it from Taobao as it was out of stock, I decided to DIY my own steering stabilizer from some common parts.

The basic component of a steering stabilizer is the spring, together with the mounting brackets at each end that mount to the front fork and the downtube of the frame respectively. The spring has to be sufficiently strong to hold the front fork, yet have some play to allow normal steering.

The spring comes from an unused kickstand, which seems to have a suitable length and spring force.

The L-shaped mounting bracket is something that I found from my box of random hardware, and it fits nicely on the back of the front fork.

Basic construction of the DIY steering stabilizer. One end of the spring is held to the front fork by a bracket, while the other end is fixed to the cable holder.

One end of the spring is hooked around the bolt that fixes the cable holder to the frame. Since the force is transmitted through the metal bolt, there is no strength issue here.

The other end of the spring hooks onto the L-shaped bracket, and is fixed to the front fork using the fender mount.

After that, it is a matter of adjusting the spring force to ensure that there is little or no spring resistance during normal steering. On the other hand, the spring force will be activated when the handlebar is rotated beyond a certain angle. This is adjusted by stretching and deforming the spring.

After installing the spring, the handlebar will encounter resistance when rotated beyond 20 degrees to either side. This is more than the steering angle required for normal riding.

As shown here, the spring prevents further movement of the handlebar, which enables the bike to be parked this way without falling over.

When the bike is held by the saddle, the handlebar can only rotate naturally 20 degrees to either side. Does not affect steering at all.

DIY steering stabilizer fixed under the downtube of the bike, and is not obvious at all.

With this steering stabilizer installed, parking this bike is now easy, with little risk of the bike tipping over. Riding and steering of the bike is not affected at all because there is almost no spring resistance at normal steering angles.

If you have the same problem with your bike, this steering stabilizer will solve the issue!

Saturday, August 13, 2016

Merida Scultura 5000: Di2 Battery Draining Issue

The Ultegra Di2 upgrade was recently done on the Merida Scultura 5000 road bike, and I really like the effortless and easy shifting offered by the electronic shifting system. It was working well for a few weeks, but one day I realised that the battery was flat just as I was going out for a ride.

This is a very unusual situation, as I always charge the Di2 battery once the battery level drops to 50% or less. Also, the Di2 battery is supposed to last a long time, even more so if you are not using it often. As I have been using Di2 since I upgraded the Dahon Boardwalk 3 years ago, I am well aware of the battery life of the system.

My first suspicion was that one of the shifter buttons had been depressed continuously during storage, as there was a chance that another of my bike could be pressing on the shifter buttons on the Merida road bike. However, upon charging up the battery to 100% and leaving it for a couple of days, the battery level dropped to 60% even without touching the bike.

The next suspicion was a faulty battery. This was a possibility as the battery was already 3 years old, and there was a chance that the battery life has been compromised. I swapped the battery with the other one on the Dahon MuEX, and monitored the battery level on both the bikes for a few days. With both batteries at 100%, we will see if it is the battery issue or some other problem.

The result was that the battery (from the Merida) remained at 100% on the Dahon MuEX, which ruled out a faulty battery. On the other hand, the battery (from the MuEX) that was installed on the Merida went down to 80% after just one day, without any usage. Further monitoring saw the battery level drop by about 20% every day.

With the battery level dropping rapidly, by around 20% a day, this was definitely not normal. Something was wrong with the system, but it is going to be tricky to diagnose the source of the problem. Most of the components are ported over from the Wheelsport Fantasy mini velo, and it had worked perfectly. The only differences are the wiring in between the components, as I have used different lengths of wires. For some unknown reason, there is a problem with the Di2 system on the Merida road bike that is causing serious battery drain.

Current Di2 wiring layout on the Merida road bike

In order to troubleshoot the battery draining issue, I had to isolate the components one by one to see which is the component causing the battery drain. The obvious place to start would be from the battery. Since I have already confirmed that the battery is working fine, the next component to test would be the battery mount.

I plugged the battery into the battery mount, and disconnected the battery mount from the rest of the system. Wait one day, reconnect the wiring, and check the battery level with the Garmin Edge 510. The good thing of having the Garmin to check the battery level is that it has a digital readout of the battery level, at every 10% intervals. This is more precise than having to read the blinking lights on Junction A to determine the approximate battery level.

No battery drainage detected with just the battery mount connected, so I continued by connecting more components to the battery (through the battery mount).

Connect battery mount to Junction B, disconnect all RD, FD and Junction A from Junction B. No battery drainage, so I moved on to connect just the FD, followed by just the RD, and so on until the entire system has been tested individually for battery drain.

This is very time consuming, as it takes one day to detect any battery drain, so testing the entire system component by component took more than one week.

I eventually found that there is battery drainage when Junction A is connected to the system, but the RD, FD and shifters are not connected. It seems that Junction A might be the one causing the problem. In order to test the hypothesis, I borrowed a new Junction A to swap with my current Junction A.

The new Junction A is the three port type, unlike the older Y-junction EW67 type that has two integrated wires for the shifters. With this new EW90 Junction A, there is a need for two separate wires to connect Junction A to the two Di2 shifters.

New 3 port Junction A, SM-EW90-A

With the new Junction A wired up, I monitored the Di2 system for a few days, and was glad to see that the battery is no longer draining fast. Under normal circumstances, the Di2 battery level can stay at 100% for at least a couple of weeks if it is not used. I did not wait that long, but the battery level did stay at 100% after a few days, which is much better than the 20% drain per day.

I was glad to see that the Di2 components are working fine, and that the problem was actually due to a faulty Junction A. Not sure why this problem will surface suddenly after working fine for these few years, but I am glad that this can be easily solved with a new Junction A.

After waiting for a few more days to confirm the diagnosis, I was sure that the old Junction A was the problematic component. With that, it is time to formally swap in the new Junction A onto the bike!


New 3 port Junction A with the mounting bracket and the rubber strap. This will normally be installed on the stem. 3 more wires are needed to connect Junction A to the two shifters.

Original Ultegra EW67 Junction A, with the two wires for the shifters built into it

3 port Junction A installed onto the Merida bike for testing and monitoring

Rubber strap with bracket mount installed on the stem. The rubber strap needs to be cut to the correct length.

Junction A clipped in under the stem. There is a charging port on this Junction A, but it only works if the new internal Di2 seat post battery is used.

Two wires lead to the two shifters, while the third wire leads to Junction B.

The other side of Junction A has the LED indicator lights, for indicating the derailleur adjustment mode or to indicate battery level.

Similar wire routing with the new Junction A, using the cable wrap to keep things neat and tidy

With the new Junction A, there is no longer any battery draining issue. The Di2 battery can last a really long time with some light usage. Glad to be able to find the source of the issue and solve it with a change of Junction A.

Sunday, July 17, 2016

Merida Reacto 4000: Part 3 - Full Components Specifications

After taking the effort to disassemble and clean all the bike components on the Merida Reacto 4000, it is time to assemble back everything. Also, it is a good chance to take a look at the stock specifications for this bike.

Part 1: Introduction and Disassembly
Part 2: Disassembly (continued) and Restoration

Other than cleaning the disassembled components, the bike frame was also cleaned and waxed to get a nice glossy finish. Here are the pictures showing the results!

Large downtube with bottle cage bosses

After waxing the frame for a couple of times with Hi Glaze 88, it is now glossy, maybe even more than the original condition!

View of the rear triangle

View of the seat tube. All clean and glossy.

The D-shaped aerodynamic seat post, with the special rubber insert for added comfort

Hidden seat post clamp for a clean appearance. Works well with no slippage.

Now, let's take a look at the component specifications for this bike. Before the cleanup, it was not ideal for highlighting the various components as they are too dusty. With all the components cleaned and restored, this is the best time to show the component specifications.

Shimano 105 5800 2x11 speed road shifters. Reliable performance at a great price point.

The damaged silver name plate was changed to a new one

Controltech aluminium stem. This seems to be a 110mm length stem.

Internal cable routing, with the shifter cables running into the top of the top tube, through a plate specially designed for this purpose.

Tektro direct mount brakes, works OK but lacks power and smoothness compared to Shimano direct mount brakes.

One way to improve braking power is to change out the original Tektro brake pads, to the Shimano brake pads taken off from the Shimano Ultegra 6800 brake calipers.

The rear section of the rear brake caliper outer casing was changed out to a new section, as shown here. It exits from the side of the downtube and routes in a smooth curve to the rear brake caliper, which is mounted under the bottom bracket.

Another view of the hidden rear brake caliper. Maybe good for aerodynamics, but troublesome for adjustments, and braking feeling is not really good due to the longer and more complex cable routing.

FSA BB386 crankset with the Shimano 105 5800 front derailleur. All cleaned up and looking new.

View of the crankset from the left side

52/36T chainring combination, which is a popular mid-compact gearing nowadays. Shiny chain and clean chain rings.

Totally cleaned up drivetrain, front derailleur and bottom bracket area. Way different from the dusty condition when we first got the bike.

Shimano 105 5800 11 speed rear derailleur

Shimano 105 5800 11-28T 11 speed cassette, all clean and shiny again!

Even the tires and rims were cleaned by wiping with a wet rag. Looking new again! Continental Ultra Sport tires, 700x25C for a bit more comfort compared to 23C tires.

No more dusty spokes! The quick release axles were changed to Shimano QR for better clamping force. To see the difference between Good and Bad QR Axles, click here.

Overall weight of 9.0 kg without any accessories or pedals. Not lightweight, but acceptable for this aero setup, with a heavier frameset, heavier high profile wheels and also the not-so-lightweight Shimano groupset.

Front view of the restored Merida Reacto 4000

Looking fast with a small frontal area

Aero frame looks good with these high profile rims

With the bike fully restored, it looks like a brand new bike again!

All it needs now is to put on a pair of pedals, and it is ready to roll!

With this bike restoration, I have learnt more about this bike and the setup. For those who are considering an aero road bike with a good component specification, this is one bike you can consider. If you have a larger budget, you can consider the higher grade Merida Reacto 5000 which has Ultegra components.

Friday, June 24, 2016

Merida Reacto 4000: Part 2 - Disassembly (continued) and Restoration

This continues from the first part of the Merida Reacto 4000 disassembly, where the stock bike was being dismantled for cleaning. As the bike was quite dusty, it was necessary to remove the components for proper cleaning.

The next component to be removed was the crankset. As this is not the more common Hollowtech II crankset, it took me a while to figure out how to remove the crankset. Luckily it did not require any special tools, or it would not have been possible to remove it.

As a FSA Goassamer crankset, it is considered a mid-high end crankset, much like the Shimano 105 crankset. This FSA crankset does have a larger spindle which is 30mm in diameter, which is bigger and stiffer than the 24mm Hollowtech II type of spindle. Also, it has a BB386 spindle, which means that it is BB30 compatible, with a press fit BB width of 86mm.

Large diameter BB386 spindle looking pretty stiff

Weighs 519 grams on the right side including 52/36T chain rings

251 grams for the left crank arm, including the integrated crank bolt

Total weight of 777 grams including the spring washers. Very similar to the weight of the Shimano 105 5700 crankset.

Overall view of the clean crankset

Press fit bottom bracket in the frame. Nice and clean now!

After removing the crankset from the frame, it was easy to clean up the bottom bracket area. As it is a press fit bottom bracket, it is not worth the trouble to remove the bottom bracket.

Also note the rear caliper brake which is mounted underneath the chain stays, supposedly for better aerodynamics as compared to being mounted on the seat stays. It is also a direct mount brake, which should give better braking force as compared to the usual type that is mounted with the centre bolt. One major disadvantage of being mounted underneath is the difficulty of servicing the brakes. Most of the time, it is necessary to remove the crankset or chain rings to make adjustments to the brake, as the chain rings will block access to the brake.

This bottom mounted rear brake also does not have a quick release adjuster, which makes it more troublesome to remove the rear wheel. More elaboration on this issue can be found later on.

Bike frame is flipped upside down for better cleaning of the rear caliper brakes.

In order to allow the rear wheel to be removed, the rear caliper brake needs to be opened up. However, since there is no quick release adjuster, Merida added an inline cable adjuster to the rear brake cable, near the handlebar area (shown below). However, this is not ideal as it is not as convenient as a quick release lever, and is it not possible to get back the same cable tension setting after removing and installing the wheel.

Original setup, with the inline cable adjust for the rear brake.

A better solution is to use an inline quick release adjuster, such as the Shimano SM-CB90 Brake Cable Adjuster, which has a quick release lever. This should have been used, instead of the stock cable adjuster, since the rear brake does not have a quick release lever. I decided to change the stock adjuster to the SM-CB90 brake cable adjuster for future convenience.

At the same time, since the original brake cable adjust needed to be removed anyway, I changed out the rear section of the brake outer casing to a new section. This involved some internal routing through the frame, and so it took quite a bit of time and effort.

Changed to the SM-CB90 Brake Cable Adjuster, which is the correct part to match the rear brake caliper.

Rear section of the brake cable outer casing, passing through the frame

Direct mount front caliper brakes by Tektro. Cleaned and lubed for smooth operation.

Scuffed right side shifter and name plate, which was probably sustained at the same time as the scratches on the rear derailleur.


Cassette is clean and shiny after a thorough cleaning. As you can see, there is very little wear on the sprockets which means low mileage on this bike.

The shifters were not removed, because they were not really dusty, and also because it was too troublesome to remove the bar tape and the shifters. With that, the disassembly is complete!

Now, since most of the components are already off the bike, I took the chance to clean and wax the bike frame. As a bike frame with a glossy finish, it is great to make the frame nice and shiny again.

It is now time to reinstall all the cleaned up components. Assembly in progress!

Bike is partially assembled, to be continued!

Part 3 to be continued