Two more blog posts to finish writing about the upgrade of the Fnhon Ultegra Di2 12 speed folding bike. The bike itself is already very good, however I decided to transfer some components from another bike over to this Fnhon bike. After all, we can't let a good carbon wheelset go to waste.
When I changed the wheelset on the Birdy AXS 12 speed to the Suncord 4 spoke carbon wheelset, the Ascent Cirrus Elite carbon wheelset was taken off the Birdy. Although the Ascent Cirrus Elite wheelset was meant to be a Birdy-specific wheelset, I realized that it can be fitted to normal folding bikes with the clever use of an adapter.
With an offset adapter for 6 bolt rotors, the brake rotor position on the Birdy-specific hub can be adjusted to match that of a normal front hub. That is the adapter that I will use to fit this Ascent Cirrus Elite wheelset (Birdy-specific rotor position) onto the Fnhon bike (standard 100 mm front OLD).
Note that the Fnhon was previously using a lightweight aluminium wheelset in 451 size, which was inherited from the original Fnhon DB12 in flat handlebar. This is the exact same Fnhon Tornado frame that was used to build the Fnhon Ultegra Di2 12 speed with a 3 way swap.
Now, the wheel size will be reduced to 406, since the Ascent Cirrus Elite wheelset is of a smaller 406 size instead of 451.
Ascent Cirrus Elite carbon wheelset in 406 size, with new tires and inner tubes ready to go.
New Panaracer Minits Lite tires in 32-406 size, exactly the same as what I am using on the Birdy AXS 12 speed.
A normal butyl inner tube weighs 104 grams...
...but a lightweight TPU inner tube only weighs 25 grams!
Ashima Ai2 super lightweight rotors! More holes than material on it. These have a diameter of 160 mm and 140 mm.
Here is the small adapter which is 5 mm thick, used to push the rotor position 5 mm outwards to make it compatible to normal bikes.
Adapter goes in between the rotor and the hub, to be fixed with a longer rotor bolt.
I used these black titanium bolts which needs to be longer than usual, due to the adapter. Bolt heads are rather big but still fits.
Rotor bolts cannot be too long either, or it will interfere with the hub shell or spokes.
Adapter sandwiched between the hub rotor mounting and the 6 bolt rotor. The rotor position is now at the standard position, instead of being 5 mm inwards as found on a Birdy.
Tires, inner tube, rotors all mounted!
Lightweight rotor ready to be tested
Ascent Cirrus Elite 406 carbon wheelset ready for installation onto the Fnhon Ultegra Di2 12 speed folding bike.
Since I was removing the old 451 wheelset and installing the new 406 wheelset, I decided to do a weight comparison as well. Not a completely fair comparison as some of the components are different, but it is an accurate representation of the weight difference due to this wheelset change.
451 aluminium rear wheel including tire, inner tube, rotor, weighs 1092 grams.
451 aluminium front wheel including tire, inner tube, rotor, weighs 970 grams.
406 carbon rear wheel including tire, inner tube, rotor, weighs 936 grams.
406 carbon front wheel including tire, inner tube, rotor, weighs 844 grams.
Overall, changing from the aluminium to the carbon wheelset (including change of tires, inner tube, rotors) saves 282 grams, which is pretty significant.
The wheel size is also reduced from 451 to 406, which means a reduction in overall gear ratio. That will be addressed separately through the drivetrain.
406 carbon wheelset on the left, 451 aluminium wheelset on the right. Big difference in rim profile and also overall diameter.
Ultegra CS-R8100 11-34T 12 speed cassette installed!
There is no issue converting the Ascent Cirrus Elite carbon wheelset from Birdy usage to general folding bike usage, all it takes is the small rotor adapter and some rotor bolts.
In the next post I will show the wheelset on the bike, along with some other changes to address the change of gear ratio due to the smaller 406 wheelset.