Fnhon Ultegra Di2 12 Speed: Ultegra R8100 Crankset and new Kickstand

Final post for the Fnhon Ultegra Di2 12 speed folding bike! In the previous post I prepared the Ascent Cirrus Elite carbon wheelset for use on this bike. Due to the change of wheel size from 451 to 406, the gear ratio has been reduced by approximately 10%.

As the gear ratio should be carefully chosen to match the usage and rider's abilities, any significant change in the gear range will affect the suitability of the gearing. The previous gear range was 30 - 92 gear inches, which is ideal for climbing and relatively fast rides on the road.

However, changing the wheel size from 451 to 406 will cause this gear range to decrease to 27 - 84 gear inches, which does not have sufficient top speed for road riding.

Therefore, the easiest solution is to increase the chain ring size to compensate for the smaller wheel size. A Stone 46T narrow wide chain ring was used, and this will be changed to a larger 50T chain ring.

Stone 50T narrow wide chain ring. Weighs 118 grams, which is 20 grams more than the 46T version.

Compatible to Shimano 12 speed chains, and also the Shimano 4 arm road crankset BCD.

Close up look at the narrow wide teeth, for good chain retention. Chamfered teeth to reduce driving noise.

New 50T chain ring installed on the Ultegra R8100 crankarm! Along with my iconic coloured chain ring bolts.

Alongside the left crankarm

Right side crank arm with 50T chain ring weighs 480 grams

Left crank arm with crank arm fixing bolt weighs 195 grams

Total crankset weight is 675 grams, which is decent. This is the same Ultegra R8100 crankset that was on the Focus Paralane. After I disassembled that bike, I reused the components across a few of my other bikes. Now, the Fnhon Ultegra Di2 12 speed bike has a full Ultegra R8100 groupset.

After swapping from 451 to the smaller 406 wheelset, the kickstand does not work so well any more. The kickstand length is important, as it determines how much the bike tilts when parked. It is related to the wheel size, as a larger wheel diameter means that the axle height of the bike is higher.

With smaller 406 wheels and previous kickstand (optimized for 451 wheels), the bike angle is too straight when parked. This causes it to tilt over very easily.

I ordered a shorter kickstand to replace the original kickstand.

Original kickstand for 451 wheels weighs 158 grams

New shorter kickstand for 406 wheels weighs a bit less at 152 grams

With the correct kickstand, the bike leans to the side a bit more, which is what I wanted. Too little or too much tilt makes the bike unstable.

New shorter kickstand also helps to create a bit more clearance with the rear rotor when put up.

There is little space to fit a kickstand between the rear rotor and the rear wheel spokes.

With the new kickstand installed successfully, the modification of the Fnhon Ultegra Di2 12 speed folding bike is completed! Below are the pictures of the bike in its final state (I think). It has evolved a lot over the years, starting from a 11 speed flat handlebar setup with XTR Di2 components, to its current drop bar setup with 12 speed Ultegra Di2.

Ascent Cirrus Elite front wheel with new Panaracer Minits tires and Ashima Ai2 rotor!

5 mm adapter added to push out the rotor, from the Birdy position to the standard position.

Same setup for the rear wheel, but with a smaller 140 mm diameter rotor.

Shimano Ultegra R8100 crank arm, with Stone 50T narrow wide chain ring.

Here is the refreshed drivetrain! Matte grey rims and crank arms give a different look. The rear derailleur has a custom short cage to have more ground and tire clearance.

Full bike view with high profile carbon rims but smaller 406 wheel size.

Previous setup with larger 451 wheels but low profile rims. I like both even though they give off different vibes.

All the components you see here are high end stuff!

Saved 200+ grams with these upgrades. Now the bike weight (excluding pedals and kickstand) is just 9 kg! Just slightly more than the flat handlebar Fnhon DB11 setup.

Extra pictures of the bike out for test rides. Here is the giant pumpkin at Elementum, near Buona Vista.

At the old Bukit Timah Railway Station.

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.