Birdy AXS: Dura-Ace R9100 Crankset

Here is a short post to show the change of crank arms on the Birdy AXS, from Ultegra 6800 to Dura-Ace R9100. I have used this R9100 crankset on many different bikes before, the most recent of which was the Specialized Aethos, when I paired this 11 speed crankset with Dura-Ace Di2 12 speed components. Previously the R9100 crankset was installed on the Fnhon DB12 folding bike.

Comparing the R9100 crankset taken off the Specialized Aethos, to the R9200 crankset which I was going to install. Detailed Dura-Ace crankset comparisons here!

For the Birdy AXS 12 speed, I only needed a single chain ring, so I took off the stock outer and inner chain rings, and installed a Wolf Tooth Drop Stop chain ring.

Single speed 44T chain ring installed on the R9100 crank arms.

Relatively small 44T chain ring, as it was used on the Fnhon DB12 which has larger 451 wheels and a small 10T sprocket.

Installation was easy as it was a straightforward swap from one Shimano crankset to another.

No change in chain length as the chain ring size remains the same.

I think the bike looks better with this gloss black R9100 crank arms, compared to the previous Ultegra 6800 crank arms which are dark grey.

Great sunrise photo taken along Neo Tiew

Taken at Teck Whye View Playground, together with the Bestrider Pump Pro 20 kids bike.

Did you notice the new component on the bike? To be revealed in the next few posts!

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!

Specialized Aethos: Assembly with new Frameset

In the previous post, I wrote about the replacement Specialized Aethos frameset, in Maroon colour. With the replacement frameset, there are actually a few options for me.

1) Sell the new frameset and buy another frameset to build up. Cannondale? Trek? Etc.

2) Sell the new frameset, and also the components that I removed from the Aethos.

3) Rebuild the bike using the new frameset and the same components.

Option 1 sounded tempting, as I could get a new frameset from another brand. However, the value of the Aethos frameset was not really good even when brand new, as the prices have dropped a lot since I first got it. In fact I think there is now excessive stock which the shops are trying to sell off.

Option 2 means having no road bike to ride, as the Aethos is my only road bike after selling away the Focus Paralane earlier. Although I do get back some cash if I sell the road bike, I think I still want to keep one road bike for the occasional fast road ride.

That means I eventually decided to go with Option 3, which is to rebuild the Aethos using the same components but the new Maroon frameset. Since I was going to rebuild the Aethos from scratch, I decided to take the opportunity to change some components as well.

I bought a new PRO Vibe superlight carbon handlebar, which is a new generation that is even lighter than the previous version! The previous version weighs 198 grams, which is already lightweight but there are a few others that are even lighter.

This time, the new handlebar is going to weigh even less, check out the actual weight below!

New PRO Vibe superlight carbon handlebar, now lighter than the previous version!

In my preferred width of 400 mm

Just 2 holes at the bottom for the hydraulic brake hoses, instead of 4 in the previous version. It is assumed that you will be using wireless road shifters.

Hole near the drops for routing the hydraulic hose internally from the road shifters to the middle of the handlebar.

Oval hole at the back of the handlebar enables Di2 wires to be routed into the stem, if necessary.

Side view shows a short reach and a standard drop shape, with a flat horizontal end.

See how thin the walls of the carbon handlebar are! Good manufacturing and quality control is needed to ensure that the wall thickness is consistent and fulfils the minimum requirement. It's a delicate balance between weight and strength.

Handlebar is really lightweight at just 160 grams! 38 grams lighter than the previous handlebar.

Inclusive of the Specialized S-Works SL Stem, the stem + handlebar combo weighs just 275 grams! Lighter than many integrated carbon stem + handlebar combo.

Although the new handlebar saves 38 grams of weight, the new Maroon Aethos frameset weighs 56 grams more than the old frame, so there is a net increase of 18 grams. Although it is nice to keep the weight low, I have realized that adding a little bit of weight here and there is not going to matter at all.

Since the components have been completely removed from the bike, I took the chance to clean up the Dura-Ace R9200 cassette as well. Once again, I used the Ultrasonic cleaner to make sure that the cassette is as clean as can be, with minimal effort from me.

Dura-Ace R9200 cassette to be installed onto the Shimano Road L2 spline freehub body, on the Dura-Ace R9270 C50 wheelset.

Shiny cassette after cleaning, looks as good as new!

As the new frameset came with a new fork as well, this means having to cut the fork steerer tube to the correct length again. Since my home workshop is pretty comprehensive, with all the right tools that are commonly used, I was able to do this job at home.

Marking the section to cut, after fitting on the stem for confirmation.

Using the table clamp to hold onto the Topeak Saw Guide, and cutting with the carbon blade on the Park Tool Hack Saw.

After cutting, the fork weighs only 286 grams! 16 grams was removed by cutting it to my required length. This is one of the lightest forks you will ever see.

Specialized S-Works SL Stem installed, with the lightweight expander slightly recessed as per instructions.

Front part of the frameset is ready, with the fork, headset and stem installed.

Glittery Maroon paint job! Looks awesome in sunlight, much like the Cervelo Aspero.

The Maroon colour looks better and better by the day!

With a new frameset, the excitement of building a new bike is here again. At the same time, there is the reassuring thought that I have done this before, and all the components have already been tried and tested to fit this frameset. In fact, even the chain can be reused as it is still in good condition and of the correct length.

For a detailed part by part analysis of the Specialized Aethos, check out the original series where the Champagne Pink frameset was first assembled!

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.