When the Cervelo Aspero is used as a road bike, the wheelset that is used is the Reynolds Assault Limited Edition carbon wheelset. It is the stock wheelset that came on the Canyon Endurace 3 years ago.
That is a good wheelset that has the latest standards even by today's standards, as it has 21 mm internal width rims and was already disc brake ready with front and rear 12 mm E-thru axles. The weight was pretty decent as well, with a weight of 1637 grams for 41 mm rims.
To be fair, I didn't need to change the Reynolds wheelset, as I had no problem with it. However, I decided to try a new pair of carbon wheels, with an even higher rim profile. Another reason was having the soft sounding rear hub on the new wheelset, which freewheels softly instead of loudly like most hubs.
Personally, I like hubs that freewheels softly, instead of loud ones. Also, a hub that freewheels softly also means less energy loss due to the loud clicking sound, although I'm sure this energy loss is quite negligible.
At the same time, the new pair of carbon wheels will also be more lightweight, at a claimed weight of just 1500 grams for the pair. Let's take a close look at these wheels!
Looks very generic with no visible brand or labels...
...until you light it up with a flash! The DarkLight 3M reflective stickers show up very brightly when it is lit, which is really useful for side visibility if you ride in the dark.
Ascent Bikes is a good local bike brand which can customize many things for you.
I have tested and customized a few bike components from Ascent Bikes before, here is what I can remember:
1) Ascent Bolt mini velo - Great looking, lightweight mini velo that can be built exactly how you want it.
3) Custom lightweight 451 wheelset with Centerlock disc brake hubs for the Fnhon DB11 folding bike.4) plus many other small items and components like handlebars, saddles, crankset, etc.
The Zenith Elite road wheelset as shown here comes with a choice of different hubs, to suit your desire for loud, soft or silent hubs.
Instead of rim tape, it comes with plastic spoke hole plugs to cover up the holes on the rim.
This is a 24 hole rim, which is enough to build a strong and lightweight disc brake wheelset.
The spoke hole plug just snap fits into each spoke hole, to cover up the sharp edges of the holes.
24 plastic spoke hole plugs weigh just 4 grams in total
Plastic rim tape weighs more at 22 grams.
A cloth rim tape would weigh even more than plastic rim tape. In any case, I think the only reason to use plastic spoke hole plugs is to save weight, as they add only a few grams of weight compared to normal rim tape. I can't think of any other tangible advantage or disadvantage for using spoke hole plugs over normal rim tape.
Rim is of the traditional hooked type. It is also not really tubeless compatible as there are no shoulders on the inside of the rim for the beads of tubeless tires to seat properly.
Internal rim width of just 17 mm is also old school, which is good for road tires but not wider gravel tires. Just for comparison, the Reynolds wheelset that is 3 years old already had an internal rim width of 21 mm.
External rim profile is nice and smooth with a slight rounded profile.
External rim width is 28.5 mm at its widest point.
Rim height is 50 mm as claimed. This makes it a proper high profile wheelset for good aerodynamics.
Front hub is a Hubsmith which is a good quality hub that is becoming popular on Birdy and Brompton folding bikes.
Centerlock disc brake rotor mounting! It is becoming more popular nowadays which I am glad to see, as it makes changing rotors so much easier than 6 bolt rotors.
With the hub caps removed, the NTN LLU bearings can be seen. Slightly more seal drag but it has better weather resistance.
This is the unbranded rear hub which freewheels softly. It uses magnetic pawls! I wonder how it works.
Curious me took apart the rear hub to take a look. 30 small ratchet teeth on the inside of the rear hub to engage with the pawls.
Freehub body with the 4 pawls removed. The pawl springs only keep the pawls in place, but do not push it hard against the ratchet. This is what allows the hub to spin softly instead of loudly.
Note the large yellow coloured bushing on the inside of the freehub body. This bushing replaces the bearing that usually seats on the inboard side of the freehub body.
Why a bushing? From some research that I found online, a bushing is apparently better at load bearing compared to a bearing. Also, being a plastic bushing, it also saves weight over a metal bearing. Eventually the bushing will wear out and cause some looseness with the axle, but that will hopefully be many years down the road. It does spin smoothly, although it did give me a surprise when I saw a bushing instead of a bearing.
Here are the 4 pawls, with a small round magnet at the back of each pawl (facing outwards to the ratchet).
The pawls are directional (magnet facing outwards), so don't assemble them wrongly.
This is the correct way of assembling the pawls on the freehub body, with the magnet visible from the outside.
The way this soft hub functions is that the magnets on the pawls will be attracted to the metal ratchet, which is what pulls the pawls outwards to engage with the ratchet during pedaling. Instead of a strong spring force, only a relatively weaker magnetic force needs to be overcome during freewheeling, which allows for a softer freewheeling sound.
The rear hub seemed to be very lightly greased, so I added some freehub grease with the intention of further reducing the clicking sound during freewheeling.
However, I found that during hard pedaling, the pawl and ratchet mechanism tends to slip, causing a loud bang from the rear hub. After some troubleshooting, I found that it was due to the excess freehub grease that I added, which prevented the magnets from engaging properly with the ratchet.
Once I took apart the hub again and cleaned away the excess grease, it worked perfectly, there was no more slippage even when pedaling hard. Luckily the ratchet teeth and pawls are not damaged due to my ignorance and experimentation.
Lesson learned, don't add freehub grease unnecessarily, especially in this unique hub with magnetic pawls.
With 30 ratchet teeth, normally the engagement angle would be 12 degrees. However, since the 4 pawls are offset (2 by 2), the engagement angle is halved, to be a short 6 degrees.
Engagement angle: 6 degrees
Points of engagement: 2 pawls at any one time
Some people mix up points of engagement and engagement angle, but they are referring to different things. For example, the 36T star ratchet design of DT Swiss has an engagement angle of 10 degrees, with 36 points of engagement since all the teeth engage at the same time.
With a traditional 2 pawl type design, with a 36T ratchet, the engagement angle is also 10 degrees, but just 2 points of engagement as there are only 2 pawls.
Anyway, let's move on to check out the weight of this wheelset. Another reason why I wanted to get this wheelset is because it is higher profile and yet also lighter in weight, which means better aerodynamics and also less inertia for wheel rotation. It is a win-win situation compared to the previous Reynolds wheelset.
Front wheel with spoke hole plugs weigh just 682 grams.
Rear wheel with spoke hole plugs are also lightweight at 822 grams.
1504 grams for a 50 mm high profile wheelset is very good indeed, although part of the reason it can achieve this low weight is due to the narrow rims. If wider modern rims are used, the weight would likely be close to 1600 grams.
I really like the soft hubs as the clicking sound is much softer than other hubs. Some people like loud hubs, but I prefer softer sounding hubs. To me, it sounds much more refined, unlike the loud hubs which sound harsh and can be quite annoying.
Another side benefit of this soft hub is the low rolling resistance during freewheeling. As there is no need to overcome strong pawl return springs, the wheel is able to roll smoothly with less energy loss to spring compression and sound. This enhanced freewheeling ability is easily noticeable compared to my other wheelsets with other hubs. It is basically free speed during freewheeling, which I would take any day!
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