Specialized Aethos: Dura-Ace C50 vs C36 Wheelset

Although the Specialized Aethos build has been completed as shown in the previous post, I am still looking for areas where it can be optimized. One of that was the wheelset that is on this bike.

For this Aethos, the priority was on building a lightweight bike, which is why I chose the Dura-Ace C36 wheelset. Using a lower profile carbon wheelset will save some weight over a higher profile wheelset.

I also have the Dura-Ace C50 wheelset which is used on the Focus Paralane all-weather commuting road bike.

Specialized Aethos with C36 wheelset on top, Focus Paralane with the C50 wheelset below.

The difference in the rim height is 14 mm, which is not so obvious unless you compare them side by side. To recap from the other post, the weight difference between the C50 and C36 wheelset is about 144 grams. Depending on who you ask, this can be a big amount or not significant at all.

C50 wheel on the left, C36 wheel on the right.

C50 wheel on the left, C36 wheel on the right.

C50 wheel on the left, C36 wheel on the right. The 14 mm height difference is obvious when comparing side by side.

Since both the C50 and C36 wheelsets are using Shimano 12 speed road cassette, of 11-30T combination, a wheelset swap is straightforward. The rotor sizes are also the same (160 mm front, 140 mm rear), even the tires are the same Continental GP5000.

The only difference is the type of inner tubes used, between the standard butyl and new TPU inner tubes.

Specialized Aethos with C36 wheelset. Looks lightweight due to the lower profile C36 rims.

With the C36 wheelset, the complete Aethos bike weight inclusive of pedals and bottle cage is 6.6 kg.

After using the C36 wheelset for some time, I changed to the C50 wheelset to see how different it feels. This means the C50 wheelset goes onto the Aethos, while the C36 wheelset goes onto the Paralane.

Dura-Ace C50 wheelset on the Aethos. I prefer this as it looks more balanced in terms of rim height to the bike.

With the heavier C50 wheelset, the complete bike weight inclusive of PD-M9020 pedals and bottle cage is 6.7 kg.

Using the 3D printed thru axle holders, which are attached to the Feedback Sports Pro Elite workstand.

Based on back to back rides on the Aethos and Paralane, there are some noticeable differences between riding the C50 and C36 wheelset on each of these bikes.

Aethos with C36 wheelset:

Original setup with lightweight wheelset. Accelerates really well due to the lightweight bike and lower inertial rims. However, difficult to achieve and hold higher speeds.

Aethos with C50 wheelset:

Takes a little bit more effort to move off from a standstill compared to the C36. However, it can maintain a high cruising speed more easily that the C36.

Paralane with C36 wheelset:

Quick acceleration, and I realized this is useful for commuting where frequent start-stops are necessary.

Paralane with C50 wheelset:

Holds speed well, but not so important for a commuting bike where speed varies a lot and there are very few chances to hold a high speed for more than a minute at a time.

After trialing the 2 different wheelsets on the 2 different bikes, I realized that the C50 wheelset is more suitable for the Aethos, while the C36 wheelset is more suitable for the Paralane.

Therefore, I decided to make this wheelset swap permanent, despite the C50 wheelset adding some weight to the Aethos compared to the C36 wheelset. In this case, I feel that the improvement in ride quality is worth the additional weight of the C50 wheelset.

With this, the Aethos bike specifications is complete. Check out the table below for the detailed breakdown of every component. Where else can I reduce weight without compromising on the performance?

Without pedals, the weight of the Specialized S-Works Aethos is just 6.2 kg.

At just 6.2 kg without pedals, this is the lightest bike that I have ever built. It is even lighter than the Java Freccia mini velo (6.3 kg), and the Canyon Endurace (6.9 kg), both of which are already very lightweight bikes. It is also much lighter than the Focus Paralane (7 kg), which is a lightweight road bike with full hydraulic disc brakes.

Specialized Aethos with C50 wheelset. I prefer how the C50 wheelset looks and rides, even though it adds a bit of weight over the C36 wheelset.

Good weather and scenery for riding bikes!

If you need a very lightweight wheelset that excels in climbing and frequent accelerations, the C36 would be suitable. On the other hand, if you need a wheelset that can hold speed better as an all-rounder, the C50 would be better, although it comes with a bit of weight penalty.

There is also a third version, which is the Dura-Ace C60 wheelset with high rigidity. That one is designed for powerful riders who need a stiffer wheelset (thicker spokes) and higher speeds (higher rim profile), but is also heavier. I don't see myself using a C60 as it is not what I need for my kind of rides.