On the Specialized Aethos, there are many high end components used, with the main objective being to make the bike as lightweight as possible.
Starting with the super lightweight sub-600 gram frame and sub-300 gram fork, even the fork expander plug is designed to shave off every gram possible. To continue with this lightweight theme, the other parts on the bike are also designed or chosen to be lightweight.
In the previous posts on the frame and fork, I shared that the thru axles are designed to rest inside a countersunk, giving a seamless look on the outside of the frame. To do so, the thru axles need to have a chamfered head to match, as shown below.
Aethos 142x12 mm rear thru axle, only 29 grams.
This gives a total thru axle weight of only 51 grams, which is super lightweight. This is lighter than the Robert Axle Project thru axles on the Focus Paralane (71 grams), and the Cervelo Aspero (129 grams, including levers).
Not only are these thru axles lightweight, there is also a brass bushing on the chamfered contact area with the frame and fork, to reduce friction during tightening.
The Aethos frameset also includes the seat post. Not because it requires a proprietary seat post due to a special tube shape, but because the seat post is a key part of the frameset if you are looking to minimize the weight. Of course, this additional component is reflected in the frameset price.
This seat post is from Roval, the sister brand of Specialized. Roval is regarded as a high end component brand, making wheels, cockpit components and seat posts.
Roval carbon seat post that comes with the Aethos frameset. Only 300 mm long to reduce unnecessary weight.
Seat post is from the Alpinist series, which is used for the lightest components.
Check out how thin the walls of the seat post are, at less than 1 mm thick!
Seat post only weighs 135 grams! And that is with a pretty robust saddle rail clamp design.
Other lightweight seat posts that I have used previously were the Hylix 25.4x400 mm seat post for the Focus Paralane (151 grams) and the Cervelo SP19 27.2x350 mm seat post for the Cervelo Aspero (188 grams). This Roval seat post is shorter and also lighter.
As this Specialized Aethos will be set up as a Di2 bike, I still need to have a Di2 battery installed somewhere on the bike. The easiest way is to install it inside the seat post, as I have done on most of my other Di2 bikes. The Focus Paralane, Cervelo Aspero and also the Fabike C3 has the Di2 battery tucked inside the seat post.
Ritchey Di2 Battery Mount, along with a black plastic shim (included with battery) to adjust the fitting of the battery inside the seat post.
Found a problem with this Ritchey Di2 battery mount, where the rubber material is interfering with the plug of the new BT-DN300 Di2 battery.
I realized that this interference is due to the new DN300 battery having a bigger plug than the previous DN110 battery. The new battery allows 3x Di2 wires to be connected to it, doubling up as a Junction B, which is why it has a bigger plug. My Ritchey Di2 battery mount is an older type which did not cater for this bigger plug size.
Anyway, it is not a big problem, as I can just cut away some material from the Ritchey Di2 battery mount to eliminate the interference.
After removing the extra material from the Ritchey Di2 battery mount, it fits the battery with no issue.
Later on, during assembly, we shall see if this Di2 battery and battery mount is able to fit inside the seat post snugly without dropping out.
What is the offset of the seatpost? Are there different options for the offset?
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