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!

Archer D1X Trail Electronic Shifter

These pictures were taken way back in 2021, but I never got around to writing this post. Now I will just publish this post so that the pictures will be uploaded to the blog.

Basically this system works by using a servo motor to pull the shifter cable by a fixed amount, actuating the rear derailleur. The servo motor is mounted at the chain stay area, and a short section of shifter inner cable links the servo motor to the rear derailleur.

When the wireless shifter is operated, it sends a signal to the servo motor to pull or release cable. The amount of cable pull or release can be set, as well as the number of gear steps. This allows this system to be retrofitted to nearly every mechanical rear derailleur in the market.

Cervelo Aspero: Super Wide Range 1x11 Speed Setup

Here are pictures of the Cervelo Aspero gravel bike with the latest super wide gear range upgrade! More pictures and links below.

Garbaruk 11-50T cassette on the Hunt 650B carbon wheelset. Looks good to me! 

Clean and fresh cassette

The cassette is even larger than the 160 mm diameter brake rotor!

Lots of cutouts on this lightweight cassette.

As the cassette size has increased from 42T to 50T, I need to add a few links to the chain. Easiest way is to use a second quick link to add a section.

Still quite a distance to the cage stopper at the rear top gear setting, after adding 4 links.

Adjusting the distance between the guide pulley to the 50T sprocket teeth.

Good clearance between the cage and the spokes even at the lowest gear.

Position of chain and rear derailleur at the rear top (11T) condition.

GRX Di2 RX817 rear derailleur with Garbaruk cage and pulleys.

Looks like the chain length can be increased, since there is still some distance before the cage stopper is reached.

Position of chain and rear derailleur at the rear top (11T) condition.

Position of chain and rear derailleur at the rear top (11T) condition.

Position of chain and rear derailleur at the rear low (50T) condition.

Cage looks very stretched!

Position of chain and rear derailleur at the rear low (50T) condition.

Position of chain and rear derailleur at the rear low (50T) condition.

Position of chain and rear derailleur at the rear low (50T) condition.

Chain only engages 3 teeth on the guide pulley when in the 50T sprocket, due to the cage angle.

Although the chain length seems to be a bit too short, the shifting and engagement all works fine. In this case I think it is OK to just do some test rides to see if the chain really needs to be lengthened or not.

There is no problem with the Garbaruk cassette at all, as I am able to shift normally up and down all the gears. Also, backpedaling while on the largest 50T sprocket is possible as well, without causing the chain to drop off the sprocket. This happened on a S-Ride 11-50T cassette long ago on the Polygon Cozmic CX3.0 MTB.

Full bike view with the large 11-50T cassette!

With the new 50T sprocket, what I gain is actually just one more lower gear of 20.5 gear inches. Seems like a lot of effort for just one more gear!

Compared to the 478 grams of the SLX M7000 11-42T cassette, the Garbaruk 11-50T cassette is a lot lighter at just 324 grams.

Full specifications of the Cervelo Aspero after this upgrade.

The Garbaruk cassette weighs 154 grams less, while the GRX Di2 with Garbaruk cage weighs 1 gram less. Discounting a few grams added back for the longer chain, there is still a significant weight reduction of around 150 grams!

It is rare that an increase in gear range is coupled with a reduction in weight, but this is all due to the lightweight Garbaruk cassette.

With an extra low gear, it is much easier to ride up steep slopes, as I can pedal smoothly instead of having to push extra hard on a higher gear.

I'm really happy with this Garbaruk upgrade, as it allows me to enjoy a super wide gear range on the Cervelo Aspero, while retaining the excellent shifting ergonomics and performance of the GRX Di2 groupset.