Finally, after thoroughly studying the Birdy City in its stock configuration, and disassembling the frameset to study the individual frame parts, I can now move on to share about the new components!
Prior to getting the Birdy City, I already had a rough idea of what I wanted to modify on the Birdy. Most of the components are decent, and would be good enough for casual riding. However, since I wanted to use the Birdy to replace my existing Fnhon DB12 folding bike, I plan to transfer most the compatible components such as the SRAM AXS drivetrain over to the Birdy.
The main major component that cannot be transferred over would be the custom 451 wheelset on the Fnhon DB12. For a start, the 451 wheel size is too big to fit on the Birdy, as it can only accept a maximum wheel size of 406, and that is with slim tires.
Next, the Birdy requires a special front hub, with inward offset hub flanges and rotor mounting. Therefore, a new wheelset is needed for the Birdy, due to the special hub design.
Whenever I want to get a new wheelset, I will always consider getting one from Ascent Bikes. I have actually gotten quite a few wheelsets from them, with some of them custom built.
3) Zenith Elite 700C road wheelset with a quiet rear hub for the Cervelo Aspero, and later the Focus Paralane.
Therefore, I decided to get a high end carbon wheelset from Ascent Bikes for the Birdy. The model is Cirrus Elite, which comes in either 406 or 451 rim sizes, and various other hubs. In this case mine is a pretty standard configuration for Birdy bikes.
Birdy Wheelset Specifications:
Birdy compatible Hubsmith front hub and rear hub.
Quick release axles.
100 mm front OLD, 135 mm rear OLD.
Shimano HG spline on the rear hub.
Disc brake mounting (only 6 bolt is available, not Centerlock).
50 mm tall 406 carbon rims with black bladed spokes and spoke nipples.
3M reflective decals (Darklight).
The wheelset is actually hand built in Singapore, with some of the components flown in from overseas. So you could actually customize it if you wanted to, subject to part compatibility and availability. I did not have to wait long for the wheelset, it took just slightly over a week.
Both front and rear wheels use 24 spokes. Rims look pretty boring here...
...until you shine a bright light on the 3M stickers! The strong reflection shows the model and logo clearly.
Front wheel of the Birdy compatible carbon wheelset. This is a 20" 406 wheel size.
Closer look at the Cirrus Elite decals and carbon rim.
The special Birdy front hub, with 100 mm OLD but inward offset hub flanges. See how narrow it is!
The rotor mounting position is also offset inwards by 5 mm compared to the standard.
Internal rim width is just 18 mm, which is considered narrow nowadays, but still wider than the set on the Fnhon DB12.
External width of these carbon rims is a generous 27 mm, which is much wider than those found on aluminium rims.
Rim height is 45 mm, not 50 mm as indicated.
In this case, although the actual rim height of 45 mm is short of the 50 mm indicated, I actually prefer it. On small wheeled bikes, the rim profile is not really important for aerodynamics, as the rim is small and the speed is slower. In my opinion, high profile carbon rims on small wheels are mainly for aesthetic purposes. You can get a similar wheelset weight using low profile aluminium rims, or even less if you use low profile carbon rims.
Here is the rear wheel of the Cirrus Elite, with a Hubsmith rear hub.
Straight pull spokes on the hub flanges, with the Shimano HG spline as the default freehub body.
Finally, let's check the weight of the Ascent Bikes Cirrus Elite 406 wheelset. Although the rims are made of lightweight carbon, the tall profile also means that it will not be much lighter, if at all, compared to low profile aluminium rims. Hub weight and choice of spokes play a part as well.
Front wheel weighs 560 grams, which is a bit lighter than the larger aluminium 451 wheels on the Fnhon DB12 (567 grams).
Rear wheel weighs 657 grams, which is also lighter than the rear wheel on the Fnhon DB12 (696 grams).
In all, the new Cirrus Elite Birdy wheelset by Ascent Bikes weighs 1217 grams, which is pretty decent for a high profile 406 carbon wheelset. It is on par with the Ridea Carbon Wheelset. If you need something even lighter, check out this SMC wheelset that has low profile carbon rims.
Compared to the heavy duty 406 wheelset (1569 grams) on the Bike Friday Haul-A-Day, it is quite a fair bit lighter. However, compared to the super lightweight Kinetix Pro wheelset (998 grams) on the Dahon MuEX, it is a fair bit heavier. Not really a fair comparison as the Kinetix Pro is a rim brake only wheelset.
In any case, I am happy with the weight and appearance of the new Cirrus Elite wheelset, let's see how it looks and performs after it is assembled onto the Birdy bike.
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