Ultegra Rear Derailleur: R8000 (Mechanical) vs R8050 (Electronic)

Here is another component comparison! I love doing side by side comparisons as it is interesting to spot the differences and try to understand why they are designed differently.

This comparison is between two Ultegra derailleurs of the same 11 speed generation. R8000 is the mechanical 11 speed rear derailleur, while R8050 is the Di2 11 speed electronic rear derailleur.

For this generation of Ultegra components, they are designed so that the mechanical and Di2 versions look similar, with the same design language. Other than the functional and dimensional differences, the visuals will be kept similar.

R8050 Di2 rear derailleur was removed from the Dahon MuSP, when it was modified from Ultegra Di2 11 speed to Sora 1x9 speed.

R8000 was newly purchased, as I wanted to cannibalize the cage set to be used for Ultegra Di2 12 speed RD-R8150 rear derailleur.

R8000 on the left with visible cable adjust bolt. R8050 on the right with the servo motor.

Ultegra Di2 Shifters: ST-R8050 (Mechanical) vs ST-R8070 (Hydraulic)

Shimano makes so many different types of road shifters that it is often hard to tell which model is for which kind of drivetrain. For braking, there are mechanical rim brakes and hydraulic disc brakes, while for shifting, there is mechanical shifting or electronic shifting.

In the previous generation of 11 speed drivetrain, there are 4 types of Ultegra shifters.

ST-R8000: Mechanical shifting, mechanical braking

ST-R8020: Mechanical shifting, hydraulic braking

ST-R8050: Electronic shifting, mechanical braking

ST-R8070: Electronic shifting, hydraulic braking

Today, I will compare R8050 and R8070, which are both electronic Di2 shifters, but with different  types of braking. I have this chance to do a direct comparison because of some related bike projects.

Some time ago, I converted the Focus Paralane all-weather road bike from 11 speed to 12 speed, thus the ST-R8070 shifters were removed from the bike.

Then, the Dahon MuSP was downgraded from Ultegra Di2 11 speed to a mechanical Sora 1x9 speed drivetrain. The ST-R8050 shifters were removed from the Dahon MuSP.

With these two shifters in hand, I can do a direct comparison before selling them away.

Can you guess which is which? For this generation of shifters, all 4 models were designed to look and feel similar.

Folding Bike 3-way Component Swap

This was a relatively complex bike modification project, as it involved 3 different bikes with many different components. Main reason for all these swapping is to upgrade to the latest components, and sell away the older and more basic components.

Flowchart showing the bikes before the component swap.

After the component swap

Fnhon Ultegra Di2 12 Speed: Geometry Comparison with Aethos

With the Fnhon Ultegra Di2 12 speed folding bike completed, I will now compare it with the Specialized Aethos. Reason for this comparison is to show the differences in geometry between an standard full-sized road bike and a folding bike with drop bars.

Before comparing bike geometry, align the bottom bracket, as this is the datum for all other bike measurements.

Both the saddles are adjusted to my height, but the Fnhon saddle is taller, as the bottom bracket is higher from the ground.

Fnhon Ultegra Di2 12 Speed: Assembly Part 2

Here is the second part of this bike build, the Fnhon Ultegra Di2 12 speed drop bar folding bike. As explained in the earlier posts, there are a few problems that had to be solved for this build to be possible.

1) Custom Di2 battery mount.

2) Short derailleur cage for the Ultegra Di2 RD-R8150 rear derailleur.

3) Narrow wide chain ring that is compatible to Shimano 12 speed chain AND Shimano 4 arm road crankset.

Here is the completed build!

Ultegra Di2 shifters ST-R8170 with good ergonomics.

Fnhon Ultegra Di2 12 Speed: Assembly Part 1

With all the problems solved as described in the earlier posts, the assembly of the new Fnhon Ultegra Di2 12 speed can now begin! I usually wait until all the required parts are available before I start building, instead of building half way and then waiting for the rest of the parts.

First step is to install the new Ultegra R8100 11-34T cassette onto the wheelset. This is the same custom built wheelset by Ascent Bikes, and with the same Panaracer Minits Lite tires as used previously.

Ultegra R8100 11-34T 12 speed cassette installed!

Using the new XTR MT900 rotors, same as the ones which I am using on the Focus Paralane.

Fnhon Ultegra Di2 12 Speed: 12 Speed Cassette, Chain and Chain Ring

After solving the issue of the Di2 battery mount on the Fnhon frame, and modifying the Ultegra R8150 rear derailleur cage to a shorter version, I am almost ready to start assembling the bike.

The drivetrain and shifting components on the Fnhon Ultegra Di2 12 speed folding bike are mostly new, except for the Ultegra R8000 crank arms which will be carried over from the Dahon MuSP. I did not get a new Ultegra R8100 crankset to match the rest of the Ultegra R8100/R8150 groupset, as I only need the crank arms and not the chain rings. Therefore, it is more than good enough to reuse the R8000 crank arms on the new setup.

Let's start with the cassette. A 12 speed road cassette is needed for the Ultegra Di2 12 speed setup, and I can choose between a 11-30T cassette or a 11-34T cassette. On the Specialized Aethos and Focus Paralane, which have front double drivetrains and are dedicated road bikes, I chose the 11-30T cassette for its tighter gear spacing.

However, for this new Ultegra Di2 setup on the Fnhon, it will be a 1x12 speed front single setup. Therefore, the gear range will be decided by the range of the cassette, while the chain ring will shift this gear range higher or lower. I decided to use the wider range 11-34T cassette on the Fnhon Ultegra Di2 12 speed folding bike.

I actually had a Dura-Ace CS-R9200 11-34T 12 speed cassette as a spare, but decided not to use it on this bike. Instead, I decided to get a new Ultegra CS-R8100 11-34T 12 speed cassette, to match the rest of the components and also to do a comparison with the Dura-Ace cassette.

Dura-Ace vs Ultegra 11-34T 12 speed cassettes.

Fnhon Ultegra Di2 12 Speed: Short Cage Conversion using Ultegra RD-R8000

Although I managed to install the Mr TiParts super short derailleur cage onto the Ultegra Di2 RD-R8150 12 speed rear derailleur earlier, it was not a satisfactory modification. There were too many issues with the modifications that can affect the performance.

Therefore, I continued to look for a better solution to have a shorter cage rear derailleur on the Fnhon Ultegra Di2 12 speed folding bike. Then it occurred to me that I should consider original Shimano rear derailleur cages that are shorter, instead of third-party ones.

Drawing from previous experience when I modified the GRX rear derailleur with an extra long cage for the Cervelo Aspero gravel bike, it may be possible to find a compatible shorter cage to replace the stock cage on the Ultegra RD-R8150 rear derailleur.

After removing the Ultegra Di2 RD-R8050 11 speed rear derailleur from the Dahon MuSP, it was available for comparison. All R8000 and R8050 mentioned below are the short cage SS version.

Long outer plate of Ultegra R8150 vs the shorter outer plate on Ultegra R8050 11 speed rear derailleur.

Fnhon Ultegra Di2 12 Speed: Super Short Rear Derailleur Cage by Mr TiParts

While planning for the Ultegra Di2 12 speed setup on the Fnhon folding bike, there are a few issues which needed to be solved. One of them was to create a custom Di2 battery holder, so that I can hold the Di2 battery on the Fnhon frame.

The other issue comes from the smaller wheel size of the Fnhon folding bike. I will continue to use the custom built 451 wheelset from Ascent Bikes, as it is a disc brake wheelset and is still very useful. The problem is that the new Ultegra Di2 RD-R8150 12 speed rear derailleur has a pretty long cage, even more so than the previous Ultegra Di2 RD-R8050 11 speed rear derailleur.

Based on the Fnhon DB12 setup, it seems that the rear derailleur cage does not have much clearance with the rim or tire. Therefore, the new R8150 rear derailleur cage might be too long. It may still work in its stock condition, but there would not be much clearance.

Anyway, I decided to try changing the derailleur cage to a shorter version, to get more clearance. In any case, I don't need such a long derailleur cage as I will be running the drivetrain as a 1x12 speed drivetrain.

Mr TiParts makes third-party rear derailleur cages that are really short. I decided to give it a try and see whether it works or not.

The R7000 version was what I had previously for the United Trifold project, but didn't use it. It doesn't seem to be compatible to R8150 which is why I got a new set on the left, for R8000/R9100.

Fnhon Ultegra Di2 12 Speed: Custom Di2 Battery Holder

Here is the first post on the reborn Fnhon drop bar folding bike! This frameset was first assembled as a 1x11 speed flat handlebar setup, using premium XTR, Dura-Ace and Di2 components.

After that, it was converted to a 1x12 speed setup, using SRAM eTap AXS for the drivetrain components.

Since then, most of the SRAM components have been transferred to the Birdy AXS 12 speed, and this is also because I want to use this Fnhon frameset for another project. This project is part of the 3-way swap that I did with the Dahon MuSP and the Birdy AXS.

As part of the 3-way swap, I will install new Ultegra Di2 12 speed components onto this Fnhon bike.

12 Speed Cassette Comparison: XTR CS-M9101 vs Dura-Ace CS-R9200

Hot on the heels of the previous comparison post (12 speed vs 11 speed): Instead of comparing within the same category (XTR to XTR, or XTR to Deore XT), I can also compare across categories, from MTB to Road. This kind of cross-category comparison is usually not meaningful, as they have very different intended usage. For example, it is not so useful to compare shifters, derailleurs or cranksets across categories.

For cassettes, cross-category comparisons are possible, because the design and intended usage is more similar. In fact, old MTB cassettes (up to 42T sprocket) has becomes the new gravel cassettes. A more extreme case is that older MTB cassette ratios such as 11-34T for a 2x10 or 3x10 speed MTB drivetrain, is now found on road bike cassettes nowadays.

Today's comparison will be rather brief, as the details of each cassette can be found in their respective posts. This time, the comparison is between two 12 speed cassettes. The XTR 10-51T CS-M9101 vs Dura-Ace 11-30T CS-R9200.

Large 10-51T 12 speed cassette, the XTR CS-M9101. It is also available in a tighter 10-45T specification.

Dura-Ace 12 speed cassette, CS-R9200 is available in 11-30T and 11-34T versions.

XTR Cassette Comparison: 11 Speed M9001 vs 12 Speed M9101

Following up on the previous introduction post on the XTR 10-51T CS-M9101 12 speed cassette, here is a comparison post that is related. Before XTR moved to 12 speed, it had a 11 speed cassette, the CS-M9001 cassette. Although both are XTR cassettes, the differences are much more than just adding one more gear.

XTR 12 speed cassette on the left has 8 riveted gears and 4 loose sprockets, while the 11 speed cassette on the right has 4 sets of riveted sprockets, and 3 loose sprockets.

XTR 12 Speed Cassette CS-M9101 10-51T

I had a chance to borrow a Shimano XTR 12 speed cassette to study, and I decided to make a few comparison posts from this. Usually, my comparison posts on cassettes are based on road cassettes such as Dura-Ace or Ultegra, as they are much more common on my bikes. I do have a few posts comparing MTB cassettes (XTR vs Deore XT vs SLX), or the S-Ride vs SRAM MTB 12 speed cassettes.

Let's take a look at this XTR cassette in detail, and compare it to other cassettes in separate posts.

Shimano XTR CS-M9101 10-51T 12 speed cassette! Also available in 10-45T specification.

All 12 gears shown here. Largest 3 gears are black in colour to help hide the sheer size of the cassette.

12 Speed Di2 Rear and Front Derailleur Comparison: Dura-Ace R9250 vs Ultegra R8150

Here is another comparison post, and a very important one at that. This may answer a common dilemma that many cyclists have: Should I get Dura-Ace or Ultegra components? As a rough guide, Ultegra components are about half the price of Dura-Ace, but nearly all the performance and just a little bit more weight, depending on the type of component.

In the previous post, I compared the Dura-Ace and Ultegra cranksets, and concluded that the Ultegra R8100 crankset is the better choice due to the very small weight savings of the Dura-Ace R9200 crankset.

Now, let's compare the Di2 rear derailleur and front derailleur of Dura-Ace vs Ultegra. Check out the differences and similarities, and decide for yourself! Let's start with the rear derailleurs.

As Di2 electronic components, the model numbers are as shown.

Dura-Ace Di2 12 Speed Rear Derailleur: RD-R9250

Ultegra Di2 12 Speed Rear Derailleur: RD-R8150

Dura-Ace Di2 rear derailleur on the left, Ultegra Di2 rear derailleur on the right.

Black glossy finish vs matte dark grey finish, see how it looks on the Focus Paralane.

12 Speed Crankset Comparison: Dura-Ace R9200 vs Ultegra R8100

One of my favourite type of blog post is to do a side by side comparison. It allows me to see exactly how the components are similar or different.

In this comparison post, two premium cranksets are compared. The Dura-Ace R9200 crankset and the Ultegra R8100 crankset.

Both cranksets here are for the Shimano road 12 speed drivetrain, with the same 50-34T chain ring sizes and 165 mm crank arm lengths.

There are many pictures here, so I will let the pictures do the talking. Check them out below!

Ultegra R8100 crankset on the left, Dura-Ace R9200 crankset on the right.

Shown at the back are the respective packaging for these cranksets.

Right crank arm comparison, both use the Shimano asymmetric 4 arm design, with 110 mm BCD.

Dahon MuSP: Sora 1x9 Speed Flat Handlebar

When I got the Birdy City folding bike, I created this plan to transfer components across these few bikes.

1) Dahon MuSP with Ultegra Di2 11 Speed

2) Fnhon DB12 with SRAM AXS 12 Speed

3) Birdy City with Sora 9 Speed

This is a good chance to refresh the components on the bike, and upgrade to something more modern. 

Key objectives:

1) Sell away the old Dahon MuSP frame with rim brakes.

2) Sell away the older 11 speed Ultegra Di2 groupset.

3) Upgrade the existing drop bar folding bike (Dahon MuSP) to Ultegra Di2 12 speed.

4) Upgrade the Birdy City to a high end folding bike with premium components.

With some planning, lots of time and effort, plus some cost, I managed to complete this 3 bike swap successfully!

Overall plan to modify these 3 bikes. The SRAM AXS components have already been transferred onto the Birdy folding bike earlier.

With the Birdy City stripped of its stock 1x9 speed Sora components, these Sora components can then be installed onto the Dahon MuSP frameset. In this post, I will focus on the specifications of the Dahon MuSP, which has a freshly installed 1x9 speed Sora groupset.

Sub-project, to convert the Dahon MuSP from a high performance 1x11 speed Ultegra Di2 groupset to a mid-range 1x9 speed Sora groupset.

Wera Safe Torque A2 Set

If you ever want to splurge on a good torque wrench, here is a good candidate. Prior to this, I have been using the same trusty Giant Torque Wrench for nearly 10 years. It is still working, but it has never been calibrated in those 10 years. Besides, it is always nice to get new tools!

The Wera Safe Torque wrench has many unique features that seem interesting to me. Check it out below!

Wera Safe Torque A2 set. There are other sets that include different types of tool bits.

Quad Lock Mag Case and Wireless Charging Pad

During the Quad Lock Black Friday sale, I managed to get a whole collection of Quad Lock related accessories for the phone. For those who have not heard of it, Quad Lock makes a whole range of accessories to fix your phone to almost any vehicle or surface. From cars to motorbikes to bicycles, you can surely find something that works for you.

A Quad Lock set basically consists of 2 main parts: The phone casing and the mount. If you have a popular phone model, the case would be readily available. Else just use the Universal Mount to stick onto a third party phone case.

The mount would be the interface between the phone case and the car/motorbike/bicycle. It is available in a wide range to suit your needs.

My first Quad Lock was for the Samsung Galaxy S8, to be mounted onto the bicycle stem. There are other mounts such as the Out Front Mount which I used when using the Wahoo Kickr Core bike trainer.

This time, I got a new Quad Lock case for the iPhone 13 Pro Max, and it is an improved version that is Magsafe compatible.

Lots of new Quad Lock stuff! Let's go through them one by one.

New Quad Lock case on the left, with a Quad Lock logo in the center.

Rubber Boot for Crank Arms

Time for a post on a random topic!

For off-road bikes such as MTB, many of them use a rubber boot at the ends of the crank arms to protect them from rock strikes or other scratches. This is almost never seen on road bikes as there is nearly no chance of hitting the cranks on anything on the road. If you do (such as during a crash), there are worse things to consider than scratches at the ends of the crank arms.

I got these Risk branded rubber boots for crank arms. They come in a generic size, and so I will see how it fits across different crank arms.

Rubber boots for crank arms! Comes in a pair, and is available in many colours.

C50 Wheelset Comparison: Dura-Ace R9270 vs Ultegra R8170

Having had the chance to have both the Dura-Ace C50 wheelset and the Ultegra C50 wheelset, it is now possible for me to do a comparison of these two wheelsets. From what I understand, there are many more similarities than differences between these wheelsets.

For areas that are not mentioned below, refer to the Dura-Ace C50 wheelset post for the details, as it means that it is the same for both Dura-Ace and Ultegra C50 wheelsets. For example, the carbon rims that are used are exactly the same, which is why they will have the same rim height and width.

Dura-Ace C50 wheelset, with 50 mm rim profile.

Giant TCR Advanced Disc 2: Ultegra Wheelset Upgrade

After introducing the Ultegra C50 wheelset in the earlier post, it will now be installed onto the Giant TCR Advanced Disc 2 road bike. This bike comes stock with an aluminium wheelset, so changing it to a carbon wheelset will be a big upgrade with lots of weight savings.

Other than changing the wheelset, new tires will also be used, since it will be very messy to transfer the tubeless stock tires (already with sealant) from the Giant wheelset to the Ultegra wheelset. The top tier Continental GP5000 tires are chosen, because they are one of the best. The normal tubed version is used instead of the tubeless version, since I still think it is easier to use inner tubes for road bikes rather than mess around with sealant. For off-road, sealant and tubeless tires are great, but not necessary for road bikes in my opinion.

Ultegra C50 wheelset with brand new Continental GP5000 tires!

Fresh wheelset and fresh tires!

Ultegra R8100 C50 Wheelset

When the Dura-Ace 12 speed groupset was launched, the Ultegra 12 speed groupset was also launched at the same time. This provided components at two different price points to suit different segments of the market. Dura-Ace for the pros and very serious enthusiasts, and Ultegra for the standard enthusiasts that don't want to spend so much for top performance.

Similarly for the new C50 wheelset, it is also available in Dura-Ace and Ultegra grades. I already have the Dura-Ace C50 wheelset and also the Dura-Ace C36 wheelset, installed on the Specialized Aethos and Focus Paralane respectively.

The Ultegra C50 is claimed to offer similar aerodynamic performance as the Dura-Ace C50, but with a lower price, at the expense of additional weight. This Ultegra C50 wheelset will be installed on the Giant TCR Advanced Disc 2 Pro Compact, as a good upgrade to the stock aluminium wheelset.

Ultegra C50 wheelset looks super plain, as the decals are grey in colour against the black rims.

I think the Ultegra logo is purposely made to be less obvious than the Dura-Ace, so as not to outshine it.

Focus Paralane: Ultegra 12 Speed Crankset R8100

The final piece of the Focus Paralane Ultegra drivetrain modification, the Ultegra crankset! I wanted to transfer the Dura-Ace components from the Focus Paralane over to the Specialized Aethos, which is why I needed to get new components.

I had already installed the Ultegra Di2 rear and front derailleurs for Shimano road 12 speed, and to complete the look, I also ordered the Ultegra 12 speed crankset, FC-R8100. This will replace the Dura-Ace FC-R9200 crankset that is currently on the Focus Paralane.

Ultegra 12 speed crankset, FC-R8100. I prefer the clean smooth design of this crankset over the edgy design of the Dura-Ace crankset.

Focus Paralane: Ultegra Di2 12 Speed Rear and Front Derailleurs

When I was building up the new Specialized Aethos lightweight road bike, I wanted to put Dura-Ace components onto the Aethos. However, it was too expensive to get another set of Dura-Ace components on the Aethos, when I already had one set on the Focus Paralane.

My solution is to move the Dura-Ace components from the Focus Paralane over to the new Specialized Aethos, then get a cheaper set of components for the Focus Paralane. Previously I splurged on Dura-Ace components for the Focus Paralane, because it was my only road bike which doubled up as an all-weather commuting bike. Also, Dura-Ace 12 speed was more readily available than Ultegra 12 speed at that time (early 2022).

Now that I have the Aethos as the pure road bike, I didn't feel the need to put the best components on the Focus Paralane. This was why I chose the 12 speed Ultegra Di2 components to replace the Dura-Ace Di2 components on the Focus Paralane.

I will be moving the Dura-Ace RD-R9250 rear derailleur and FD-R9250 front derailleur over, while I will not be transferring the Dura-Ace shifters and brakes as it is too troublesome to uninstall and reinstall them again on the Aethos. The hydraulic hose length might not be long enough which would require a hose change as well. I would rather do a fresh, hassle-free, Shimano J-Kit installation of new shifters and brake calipers on the Aethos.

Here are the new Ultegra Di2 rear derailleur and front derailleur!

Ultegra Di2 RD-R8150 12 speed rear derailleur

Shimano RX801 vs RX800 Gravel Shoes

If you didn't realize by now, I am a big big fan of the Shimano RX8 gravel shoes. Apart from the boring black colour, I probably have most of the other colours. They fit me so well, look so good and functions perfectly for my kind of rides.

RX8 in Silver Camo colour

RX8 in Cactus Berry colour

RX8 in Bronze colour

In 2022, a new generation of RX8 shoes was released. This new generation is numbered RX801, while the older first generation is RX800. In this new generation, there are some improvements made, while new colours have also been released.

One of the new colour scheme really caught my eye, and you can see it below!

New Shimano RX8 (or RX801) gravel shoes! The WIDE version seems to be the standard.

Shimano ET7 and EX7 Touring Shoes

Here is an introduction to some of the Shimano shoes that are less commonly seen or heard of. Most of the time, you hear of the latest top grade cycling shoes such as the RC9 road shoe or the RX8 gravel shoes. However, Shimano actually has a wide range of shoes that cater to nearly every cycling usage you can think of, from top level competition models to basic casual models.

For practicality and everyday usage, here are two models which I like. Check out the pictures and descriptions below to see what I think of them!

Here are two types of touring shoes, the EX7 and the ET7. Details below.

Shimano RX8 vs RX6, and RC9 vs RC7 Shoes

Here is a brief comparison of a few different Shimano cycling shoes. For gravel usage, there is the top grade RX8, versus the cheaper RX6. As for road cycling, there is the top grade RC9 (S-Phyre) and RC7. I happened to see all these models in the shop, so I decided to do a shoe comparison based on what I saw.

I really like the RX8 gravel shoes, as they use the SPD system instead of SPD-SL, which makes it much easier to walk in. Also, they have the sleek look of road shoes, without the bulk and weight of MTB SPD shoes. In fact, I like the RX8 gravel shoes so much that I have many pairs of it (and counting)!

RX8 in Silver Camo colour

RX8 in Cactus Berry colour

RX8 in Bronze colour

Shimano introduced a few new models of gravel shoes earlier this year. The improved RX801 (previously RX800, also called RX8), as well as the new mid grade RX600 (or RX6) version.

Both are RX6 gravel shoes in different colour. SRP is SGD 199.

Birdy AXS: Chain Length, Freehub Grease and QR Axle Changes

Final post on the Birdy AXS 12 Speed folding bike! At least for now, until some new project or ideas pop into my head.

Throughout the whole upgrading process from the stock 9 speed Birdy City, I have learnt a lot about the Birdy folding bike. Especially for the folding design, where it is different from any other bike.

There were a few issues which were not fully resolved earlier, but they have now been fixed. 3 of the problems have been highlighted below, along with how I solved them.

First issue was the chain length on the Birdy drivetrain. As I transplanted the SRAM AXS 12 speed drivetrain from the Fnhon DB12 folding bike, I reused the existing chain as the mileage was quite low.

However, the chain stay length of the Birdy is longer at 430 mm, compared to the 400 mm of the Fnhon DB12. Therefore, using the same chain length with the same cassette and chain ring, on a longer chain stay, makes the rear derailleur cage stretch out too much.

At the largest sprocket (lowest gear), the rear derailleur cage is very stretched out and looks over the limit.

Birdy AXS: Outdoor Pictures and Gear Ratio

With the Birdy AXS 12 speed completed, I can ride it around to many different places, and take some nice pictures. Here are some of the pictures with the fully upgraded Birdy folding bike with 20" 406 wheels. Compare this to the pictures that I took with the stock Birdy City bike.

Simple but attractive dual colour scheme, with a Sky Blue frame colour and all black components.

Long ago, I had the Dahon Boardwalk with lots of gold bling on it.

Birdy AXS: Birdy Dimensions and Weight after Modifications

After completing the modifications to the Birdy folding bike in the earlier posts, there are some bike dimensions that have been altered. This is largely brought about by the change in wheel size from 18" 355 to 20" 406, and also a few other component changes.

Fully upgraded Birdy folding bike with a 12 speed drivetrain, carbon wheelset, wireless shifting and full hydraulic brakes.

Birdy AXS: Wheel Size Comparison - 18 Inch (355) vs 20 Inch (406)

One of the major modifications that you can do on the stock Birdy folding bike is to change the wheel size. For most bikes, when you upgrade the components, the wheel size remains unchanged, since the frame is only designed to fit one wheel size comfortably. In the case of the Birdy frameset, the stock 18" 355 wheelset can be swapped for a larger 20" 406 wheelset. This means that the rim diameter is increased from 355 mm to 406 mm, a 51 mm increase.

However, if the wheel outer diameter (inclusive of tire) is directly increased by 51 mm, it will not fit in the frame properly when folded. Therefore, using a larger rim diameter needs to be complemented by a reduction in tire height. In other words, swapping from an 18" 355 rim to a 20" 406 rim requires the tire to be changed to a slimmer type (which is also shorter in sidewall height).

Therefore, if you are looking for a more comfortable ride, using a smaller 18" 355 rim will allow a wider tire to be used for more air volume and comfort. On the other hand, if you are looking for a sportier ride with lower rolling resistance, go for a 20" 406 rim with slim and slick tires.

This dual wheel size compatibility concept is the same as that found on the Ascent Bolt/Intrepid mini velo bikes, where you can go for a smaller 406 wheel with very wide tires, or a larger 451 wheel with slim tires.

In my case, I wanted a larger 20" 406 wheelset for faster road riding, which is why I changed to the Ascent Cirrus Elite carbon wheelset. I also chose the Panaracer Minits Lite tires for low rolling resistance and reduced weight.

Stock 18" 355 wheelset on the left, new 20" 406 wheelset on the right. The difference in wheel diameter is quite obvious. Rotor diameter is the same at 160 mm.

Birdy AXS: Folding Considerations for Birdy

The Birdy is a full suspension folding bike, which means that other than offering a comfortable ride through the suspension, it also has to fold down to a reasonable size.

In the earlier post, I documented how the stock Birdy City folds, and what are some of the considerations to take note of during folding. I also compared the folded size to the Fnhon DB12, as well as some of the bike geometry.

After the modifications, I have learnt a lot more about the quirks of the Birdy, especially during folding. Here are some of my findings and observations, for you to take note of if you plan to get a Birdy or do any modifications.

Starting with the front suspension fork, one of the challenge is to route the front brake hose neatly and robustly, so that it can withstand folding without damage or interference. I experimented with many different routes and also consulted many online sources to see how other people do it.

Most dealers use mechanical brake calipers or hybrid mechanical/hydraulic brake calipers, where the hydraulic caliper is actuated by a standard steel brake cable. This solves the problem of bending or stretching the brake outer casing when the fork is folded.

On the other hand, there are a few successful examples where a full hydraulic hose routing is done, and seemingly with no major issues. This is definitely my preference as I much prefer the feel of the hydraulic brake levers.

The objective is to route the hydraulic hose in a way that it does not get kinked or twisted excessively when folded, during the folding process and when fully unfolded.

After many trials with a spare hydraulic hose, I finally found something that works. The free length, fixed length (with cable tie) and curvature of the hose are all factors that determine whether the hose can move freely during folding.

Final routing, with the hose running on the inside of the fork, using a cable tie to fix the position. The direct hose connection to the XTR brake caliper matches this routing well.

Birdy AXS: Assembly Part 2

Even before I got the Birdy City, I already planned to make major modifications on it. In fact, the modification ideas have already been floating around in my head for quite some time, just that I didn't proceed with it.

For full bike modification projects, I think it is a good idea to test out the bike in its stock condition first, so that you know the baseline performance. Afterwards, when the modifications are complete, the performance can be compared so that you can appreciate the upgrades and improvements.

As planned, many of the drivetrain and components will be moved over from the Fnhon DB12, as the Birdy will be replacing the Fnhon as my go-to folding bike. As such, I won't be sharing the details of the existing components, as the information can be found over at the Fnhon DB12 blog page.

For those components that are new, the details have already been shared in the earlier posts, or you can find the links at the relevant picture captions below.

Let's start with a picture of the completed bike, before zooming into each component for more detailed pictures.

Birdy upgrade complete! The new model is now Birdy AXS 12 Speed.

Birdy AXS: Assembly Part 1

In the previous posts, the stock drivetrain and suspension setup of the Birdy City was studied, followed by disassembly of the frameset and the suspension fork.

The Ascent Cirrus Elite carbon wheelset is new, as the Birdy requires a special front hub design. Otherwise, most of the other components will come from the Fnhon DB12 folding bike, as the Birdy will replace the Fnhon as my main folding bike. That said, the Fnhon frameset will not be abandoned, as it will be used for another project. 

I got a new set of hydraulic brake calipers for the Birdy, as the existing XTR brake calipers on the Fnhon will continue to be used for the new Fnhon build. The Birdy still uses the conventional Post Mount brake mounting, both at the front and the rear, which does not allow me to use the newer Flat Mount brake calipers. As I prefer a direct hose connection to the brake caliper instead of having a banjo bolt connection, this means that I will choose the XTR M9100 brake caliper that I have used previously. Alternatives are the non-series BR-R785 and the Deore BR-M6100.

XTR M9100 hydraulic brake calipers! However, the version that is currently in stock comes with metal brake pads, and not resin brake pads.

Birdy AXS: Tire and Rotor Setup

Since I will be changing the wheel size on the Birdy from the stock 18" 355 to the new 20" 406, I will also need new tires and inner tubes. For 20 inch 406 tires, there are lots of choices as it is a very common tire size.

The limiting factor here is the frame clearance during folding, and the rear derailleur cage clearance during riding. I understand from others' experience that for this larger 20" 406 wheel size, I cannot use a tire that is too wide, as it also makes the tire outer diameter too big for proper folding.

My preferred tire for 20" 406 is the Schwalbe Kojak 35-406 tire that is 35 mm wide, as it provides the best balance between comfort and rolling resistance. However, it seems that this tire width may be too wide to be used on the Birdy. The next best option is thus the Panaracer Minits Lite tire, which comes in a slightly narrower 32-406 tire size.

I have used this tire previously in the narrower 28-451 size, on the Dahon MuSP and also the Fnhon DB12. The 32-406 size was briefly used on the Dahon MuEX many years ago, but it was replaced as it did not feel suitable at that time.

Panaracer Minits Lite folding tires.

Birdy AXS: Hubsmith Freehub Construction and XDR Freehub Body

In the previous post, I wrote about how I wanted to transfer the compatible components over from the Fnhon DB12 to the Birdy folding bike. The SRAM AXS groupset will be transferred over, but this is not so straightforward.

The SRAM Force 10-36T 12 speed cassette requires a XDR driver, which is not commonly found on small wheeled bikes. On the custom 451 wheelset by Ascent Bikes, I was lucky the Novatec rear hub has a compatible XDR freehub body which enabled the modification.

On the new Cirrus Elite 406 carbon wheelset, I checked to make sure that the Hubsmith rear hub has a compatible XDR driver, so as to use it with a SRAM cassette. The default freehub body is the Shimano HG spline design, which may be useful one day, so I will keep it around.

XDR freehub body for the Hubsmith rear hub. This is an additional part which I purchased together with the Cirrus Elite wheelset.