Cervelo Aspero: Ascent Bikes Zenith Elite Wheelset

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.

2) Custom heavy duty 20" wheelset with Deore XT hubs for the Bike Friday Haul-A-Day cargo bike.

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.

Compared to the Reynolds wheelset, the new front wheel is about 80 grams lighter, while the rear wheel is about 50 grams lighter. This new Zenith Elite wheelset has a total weight of 1504 grams, which is practically the same as the estimated 1500 grams per wheelset. In all, this new wheelset saves 130 grams over the Reynolds wheelset.

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!

Green Corridor Cycling Guide - August 2020

I just did an exploratory ride on the Green Corridor, from Buona Vista area, northwards to Bukit Timah. Here is a detailed guide on where the junctions are, and what to watch out for at each section. This information is valid as of August 2020, as some sections of the Green Corridor are still under construction.

Starting from opposite Buona Vista MRT, at point A, I started taking pictures and noting my location along the route. For this ride, I used my Cervelo Aspero gravel bike as I am expecting some off-road sections on this route.

Fully equipped for some adventure riding, with two full water bottles and a large frame bag.

The letters indicate the points where the photos shown below were taken.

Point A1: Start of Green Corridor section, this is opposite Buona Vista MRT. You will need to carry your bike down a flight of stairs, if you are coming from the road way level. Else the underpass links directly from the MRT station.

Point A1: Terrain is loose dark grey gravel. Doable on slim road tires, but go slow and make sure there is enough air pressure in the tires, or there is high risk of getting a puncture.

Point A1: Using gravel tires or MTB tires would be best as there is enough width and air volume to ride safely.

Point A2: After a short section of gravel, you will reach the paved section of the Green Corridor.

The paved section is made of stones, which are fixed into place, and has a smooth top surface that is painted dark red. Something like road asphalt, but with coarser stones. Suitable for any kind of bikes or tires.

From Point A2, you can ride the paved route all the way to Point B1, where this section of the Green Corridor ends.

Point B1: Take the stairs and exit the Green Corridor. This is located behind Cold Storage at Jelita.

Point B2: At the end of the path, you will exit beside Caltex petrol station.

This sign can be found at point B2. It is accurate as of August 2020.

This sign can be found at point B2. Suggested route on the pavement.

From point B2, take the pavement, following the suggested route as shown above. This will bring you to the next part of the Green Corridor, which is point C.

Point C: While riding along the pavement, you will come to this point, where there is an opening across the road.

Point C: This is the start of the next section of the Green Corridor. Note the gravel surface!

The entrance to the Green Corridor at point C is a gravel track. It is a narrow and steep downslope, with loose gravel. Only attempt to ride down this track if you are on a gravel bike or MTB, else it is better to push your bike while walking down.

Next section starts from point C, where I made a short detour to point D.

At the bottom of this gravel track at point C, you will reach a junction where you can turn left (northwards) or right (southwards). Although I know that northwards is the correct way to continue the Green Corridor ride, I decided to go southwards (towards point D) to see what is over there.

Point D: End of the trail, this part of the Green Corridor is still under construction.

Point D: You can exit the Green Corridor and onto Greenleaf View/Greenleaf Walk. When this section is completed, point B1 and point D will be linked.

Alternatively, instead of heading down the gravel track from point C, you can ride along the road till Greenleaf Walk, and enter the Green Corridor from here (point D).

Alternative: Instead of using the red route, take the blue route to enter the Green Corridor.

Point E: Red paved path all the way northwards. 

Point F: Beautiful photo spot! I never knew a canal could look so nice. Weather was awesome as well.

Point G: Another unplanned detour. I saw a gravel track off the side of the Green Corridor, and made a quick turn to ride down that way. I was very happy to find more gravel to ride on.

This is exactly what a gravel bike is good for, for spontaneous exploration off the usual paved path. Once I saw the gravel track running off to the side, I just turned and headed down that way without thinking. And it brought me to an awesome area, as shown below.

Point H: This park connector bisects Holland Road, and is a really nice quiet area.

Point H: This is Holland Green Linear Park, which looks like a newly completed park connector!

Point I: Dead end for the park connector, but if you climb the flight of stairs located just beside this point, you will reach Garlick Avenue, which will lead you to Bukit Timah Road.

Point J: Took a different route back to the Green Corridor. The other side of the canal does not have a park connector, so I rode on the grass all the way back to point H.

From point H, I retraced the route back to the Green Corridor, passing by point G again.

Continuing northwards, the next highlight would be the old railway station as shown below at point K.

Point K: Old railway station, and a great photo spot. It's not often where you can get a clean picture with almost no one in it!

Here's the obligatory picture of the bike with the signboard!

Point L: End of the Green Corridor for now, since the old railway bridge is currently inaccessible. This exits onto Bukit Timah Road, beside King Albert Park.

Point L: Another point of view for this entrance/exit to the Green Corridor.

From point L, if you wish to continue northwards, the shortest way is to climb the overhead bridge and cross the road. This would be much shorter than taking a long detour to the traffic light crossing.

Once across, I rode on the road along Rifle Range Road. There is another section of the Green Corridor that starts here, although it is not quite completed.

Point M: From Rifle Range Road, take the short flight of stairs up and you can continue on the Green Corridor.

Point N: This part of the route is off-road terrain, unlike any that I encountered earlier.

Point O: There is even single track to ride on! No problem for the gravel bike though.

Point P: This section of the Green Corridor ends here.

From point P, I had to find my way out of the Green Corridor, as there were no signs to indicate where to go next. After going down a steep and slippery slope, I finally ended up at Hindhede Place.

I don't recommend riding this section from point M to point P, as it is not safe to walk down the steep slope at point P with a bike. If you are trekking, it is OK, but not with a bike. There is nothing much to see along this section anyway.

The Green Corridor route ends here, at point P. The section northwards of point P (towards Hillview) is still under construction.

Point Q: Start of Bukit Timah MTB trail!

Point Q: Here is where Bukit Timah Hill starts. There is a long line of cars queuing up to go into the car park, and this area is pretty crowded. Cycling is not allowed inside.

If you want to ride on the Green Corridor, the section from point A to L is pretty good. There is a detour between point B1 and point D, but it is not a big issue. I recommend checking out Holland Green Linear Park, from points G to J.

A gravel bike or MTB would be able to ride the whole route without any issue. If you are riding a road bike or a folding bike, point C will not be rideable, but you can push the bike. Or, just take the alternative route as shown above, passing through Greenleaf Walk.

That's it! Hope the unfinished sections can be completed soon, and we can have a seamless ride all the way along the Green Corridor.