Wednesday, January 25, 2023

Specialized Aethos: Tripeak Ceramic Bottom Bracket and Dura-Ace Crankset

In the previous post, I had already started the assembly of the Specialized Aethos. After assembling the fork and headset area, I continued by testing the bottom bracket.

Normally I would not install the bottom bracket first, as the internal cabling needs to be done before that. However, since this Aethos frame uses a threaded bottom bracket instead of a press fit type, it is easy to install and test to see if it fits well. It can be removed easily just by unscrewing the bottom bracket from the frame.

During this test installation, I found that the Dura-Ace R9100 bottom bracket does not spin well at all. There was a lot of resistance, which prevented the crankset from even spinning one round when I spun it by hand.

In the end I decided to give up on using the Dura-Ace bottom bracket, as the rotation feeling is just too poor. Instead, I decided to go for a smoother spinning bottom bracket, of which there are many other options.

I considered the Hambini bottom bracket, but the price of SGD 450 for a single bottom bracket is too much for me to accept. I looked for alternatives, such as the Ascent Revolution BB, but that was a bit heavy.

In the end I decided to try this Tripeak BB with ceramic bearings, which is not too expensive at around SGD 100, while being lighter than the Ascent Revolution BB. The reason I chose the ceramic version is not for smoother operation, as at such low rotation speeds, using steel or ceramic bearings make no difference. Rather, the reason is that ceramic balls are a little bit lighter than steel balls.

Tripeak bottom bracket for 68 mm English threaded frames, and for 24 or 22 mm spindles.

On the non-drive side, there is an adapter so that you can use it with SRAM cranksets that have a stepped 24/22 mm spindle.

Here is the adapter to reduce the internal diameter on the non-drive side from 24 mm to 22 mm.

Since I am using a Shimano crankset with a straight spindle of 24 mm, the adapter is not required.

It comes with a few shims/spacers if you need to adjust the chain line, and also a wave washer if you are using a SRAM crankset that needs the pre-load from the wave washer.

Tripeak ceramic BB weighs 98 grams. It is 32 grams heavier than the Dura-Ace R9100 bottom bracket, but I accept this weight tradeoff for the much smooth rotation.

Tripeak bottom bracket installed! Since the outer diameter of the bottom bracket is larger, it matches the frame nicely.

I'm using the older Dura-Ace R9100 crankset, instead of the latest R9200. This is because the new version is 72 grams heavier than the older version, which is quite a lot.

I'm happy with the new bottom bracket as it spins so much smoother! Now I can continue with the rest of the bike build.

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