Fnhon Ultegra Di2 12 Speed: Ascent Cirrus Elite Birdy Wheelset with Ashima Rotors

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.

Specialized Aethos: Maroon Frameset and Dura-Ace R9200 Crankset

Here is how the Specialized Aethos looks, with the Maroon coloured frameset! The previous Champagne Pink frameset was replaced under warranty, and I got the chance to choose a new colour.

I decided to build it up again, with mostly the same components. There were a few components changes, but otherwise largely the same Dura-Ace R9200 2x12 speed specification.

Freshly built up with a new frameset and same Dura-Ace components!

Another view from the non-drive side.

Front view

View from the rear. See how glossy the paint job is!

Fresh PRO bar tape, with my ideal shifter angle and handlebar position.

Dura-Ace C50 wheelset is used for better aerodynamics, compared to the Dura-Ace C36 wheelset.

Everything is freshly cleaned

Just 6.7 kg including pedals! Lightweight road bike possible with this lightweight Aethos S-Works frameset.

At the Bird Park in Mandai

The first ride is a wet ride!

Love the glitter that shows up under sunlight

With lots of other road bikes, also at the Bird Park

One other modification that I later made to the Aethos is the crankset. I had previously been using the Dura-Ace R9100 crankset, which is designed for 11 speed but also works well with 12 speed drivetrains. It saves some weight over the 12 speed crankset, which is why I kept it on the Aethos.

Dura-Ace R9100 crankset: 610 grams

Dura-Ace R9200 crankset: 682 grams

However, now I decided to install the 12 speed Dura-Ace R9200 crankset onto the Aethos, to complete the groupset. There is a little weight penalty of 72 grams but I think it is not going to matter at all.

For a detailed comparison of the R9100 vs R9200 crankset, check out this post!

R9100 on the left, R9200 on the right.

Dura-Ace R9200 12 speed crankset installed

Complete Dura-Ace 12 speed groupset!

Full bike picture again, with the Dura-Ace R9200 crankset. Most people will not be able to tell the difference.

I don't have any other upgrades or modifications planned for the Specialized Aethos, as it is pretty much perfect. Highest spec frameset with highest spec drivetrain, there is nothing more I need.

At People's Park Complex in Chinatown, Singapore.

Some old school signs can be found!

12 Speed Road Cassette Comparison: Dura-Ace R9200 vs Ultegra R8100

One of the most common questions that cyclists ask is whether it is worth upgrading from an Ultegra cassette to a Dura-Ace cassette? The Dura-Ace cassette costs around 3 times more than the Ultegra version, which is a pretty big difference. Why is there such a big price difference?

Today I will compare the Dura-Ace R9200 12 speed cassette versus the Ultegra R8100 12 speed cassette. The cassette details can be found in the individual posts, as I will mainly be comparing the similarities and differences. If you like side by side comparisons, there are a lot more at this page.

Comparing the bigger 11-34T cassette instead of the 11-30T cassette.

Colour looks very different, due to the different materials and surface finishing used.

Dura-Ace cassette is on the right with some dark grey sprockets.

Construction is similar, as both use 2 spiders for 7 sprockets, while the other 5 sprockets are loose.

Ultegra CS-R8100 11-34T cassette weighs 341 grams. Heavier than the Dura-Ace and also the SRAM Force XG-1270 11-36T cassette.

Dura-Ace CS-R9200 11-34T cassette is much lighter at 256 grams. A whole 85 grams lighter.

Aluminium lock rings look similar, just with different laser engraving / pad printing.

The 11, 12, 13T sprockets are similar, but the larger sprockets are slightly different between the Dura-Ace and Ultegra versions.

On the Dura-Ace 14T sprocket (right), there is a groove cut into the sprocket to reduce a bit of weight.

Ultegra 14T sprocket is 12 grams.

The groove on the Dura-Ace 14T sprocket saves 2 grams.

The 12 speed B spacer is different. Dura-Ace uses the aluminium version on the right, while the Ultegra version uses a resin spacer.

Same for the 15T sprocket, the Dura-Ace version has a groove all around.

Ultegra 15T sprocket weighs 13 grams.

Dura-Ace version with groove is 1 gram lighter.

On the 11-34T cassette, there is no 16T sprocket. Instead, it is replaced by a 34T sprocket at the end to expand the gear range. Check out this post for a comparison between the 11-30T and 11-34T cassettes.

The 17-19T sprockets are riveted onto a small aluminium spider. The spider looks the same, but the sprockets are different!

The Dura-Ace version on the right has a titanium 19T sprocket that is riveted to the steel 17T sprocket, while both the sprockets on the Ultegra version are made of steel.

Ultegra 17-19T with both steel sprockets weigh 45 grams.

Dura-Ace version with a titanium 19T sprocket weighs 9 grams less.

Next, we move to the last spider on the cassette, where the 5 largest sprockets are riveted together. These 5 sprockets are 21-24-27-30-34T.

Dura-Ace uses titanium for its 6 largest sprockets, shown here are the 5 that are riveted together. Ultegra uses steel for all its sprockets.

Titanium sprockets have a smooth dark grey finish, compared to the sand blast satin nickel finish on the Ultegra sprockets.

Lots of rivets holding the 5 sprockets to the aluminium spider!

The Dura-Ace cassette spider on the right has a better looking surface finish, while the Ultegra version on the left looks rather unfinished.

If you look closely, the rivet head looks different! Dura-Ace uses rivets that are non-magnetic, which might be titanium, although it might also be stainless steel.

Ultegra cluster of 5 sprockets weigh 236 grams. This makes up the bulk of the Ultegra cassette weight (341 grams).

Dura-Ace cluster is much lighter at just 162 grams for the 5 largest sprockets! This is 74 grams lighter than the Ultegra cluster.

It is clear that most of the weight savings come from the cluster of 5 large sprockets, as this sub-unit alone accounts for 74 grams out of the total weight difference of 85 grams. This is possible due to the use of titanium sprockets, which are much lighter than steel sprockets.

Titanium has a density that is 4.5 kg/m3, compared to 7.8 kg/m3 for steel. If the material volume is the same, the titanium sprockets will weigh about 42% less than the steel sprockets. That is how the titanium sprockets enable big weight savings.

However, this comes as a cost, as titanium is much more expensive to procure and manufacture when compared to steel sprockets. This is part of the reason why the Dura-Ace cassette costs 3 times more than the Ultegra cassette, since half of the sprockets (6 out of 12) on the Dura-Ace cassette is made of titanium.

If you are looking for weight differences between the Dura-Ace and Ultegra groupset, the cassette contributes a big amount to it. Correspondingly, the cost difference is also big.

Is it worth paying more for the Dura-Ace cassette? Only if weight reduction is your priority. Otherwise, the Ultegra cassette would work just as well in terms of shifting performance and durability.