Cervelo Aspero: WTB Venture 47 650B Gravel Tires

As you already know, I like gravel riding, as it allows me to explore unpaved roads anytime I come across them. Previously I have tried the 700C x 32 mm Panaracer GravelKing SK tires on the Canyon Endurace, followed by the 650B x 43 mm version on the Cervelo Aspero gravel bike.

The GravelKing SK tires are nice and fast rolling, even on the roads. On light gravel trails they are fantastic as they roll really well. However, they tend to lose grip when cornering fast on loose surfaces. The result is a sliding rear end that can feel disconcerting if you are not expecting it or ready for it. This is due to the absence of raised side knobs on the tires. 

Also, the 650B x 43 mm tires were true to size, measuring 43 mm on the Hunt 650B Adventure Carbon Disc wheelset. I had purposely chosen the smaller 43 mm version, as I was expecting it to get wider once installed on the 24 mm wide Hunt rims. Since it didn't expand as I expected, I was not maximizing the tire clearance on the Cervelo Aspero frame. I would have gotten the wider 48 mm version if I knew it would be true to size.

So, I have two main reasons to change the gravel tires. The first being that the GravelKing SK does not corner as well as I like, while the second reason is because it is not maximizing the tire width available on the Aspero frame.

The Aspero frame has a maximum frame clearance of 57 mm when using 650B tires. With a recommended 4 mm clearance on either side of the tire, the maximum 650B tire width allowed is 49 mm.

After reading many tire reviews, it seems that the WTB Venture 47 650B tires may just be the tire that I am looking for. Let's take a closer look at these tires.

WTB Venture 47 650B tires. Of course I must get the brown sidewall version for the gravel look.

WTB calls 650B tires as Road Plus tires. The highlight are the rows of outer knobs for extra grip during cornering.

Tightly packed centreline for fast rolling, with lots of soft flexible ribs for grip on rough surfaces, and large side knobs for cornering traction.

Due to some quirk of manufacturing, they are labeled as 44-584 tires, which is different from the 47 mm tires that they are advertised as.

These tires are heavy! At 550 grams, they are 300 grams more than a typical 28 mm wide road bike tire. This is due to having much more rubber and width on the tire.

When mounted on the wheels, this is the actual tire profile. Ideally, only the centreline portion will touch the road when riding on smooth paved surfaces.

Lots of flexible ribs for extra grip on loose and uneven terrain.

Actual tire width is just over 47 mm when measured across the knobs. This leaves about 5 mm of tire clearance on either side of the tires.

If you measure without the knobs, it is about 45 mm wide.

WTB + Hunt! Tire height is a lot taller than the shallow Hunt rims.

Venture 47 650B Road Plus is the model of this WTB tire.

Both tires installed onto the Hunt wheelset. With inner tubes for now.

Looking good! Very gravel-like appearance.

Front wheel weighs a massive 1538 grams, inclusive of wheel, tire, inner tube and rotor.

Rear wheel weighs exactly 2 kg, including the wheel, tire, tube, rotor and also the 11-34T cassette.

As you can see, having a gravel wheelset with wide gravel tires is heavy, mainly due to the heavier tires and larger inner tube required. Any weight savings from a smaller 650B wheelset is totally cancelled out by the tire weight. On the other hand, a MTB tire weighs even more, so a gravel tire that weighs 550 grams seems lightweight in comparison.

6 mm side clearance between the front tire and the front fork. Lots of clearance in the radial direction too.

Lots of clearance at the rear seat stays as well.

Another view of the tire clearance at the rear seat stays.

5 mm tire clearance at the chain stay area, which is the area on the frame that has the smallest clearance. I'm very comfortable with this amount of clearance.

View of the rear wheel with WTB Venture 47 650B tires.

Here is how the whole bike looks with the wider and more aggressive Venture 47 tires!

View from the drivetrain side. I really like how the change of wheelset totally transforms the bike's character.

The tires in its natural habitat! Works super well on loose gravel and sand as seen here.

With these new tires, I am able to corner faster with more confidence, as the pronounced side knobs are effective in providing traction during cornering.

A downside of having lots of flexible ribs is that lots of small stones are collected between the ribs. Doesn't bother me too much, as they tend to fall out on their own after some riding.

Full list of component weights, updated with these WTB Venture 47 tires.

Cervelo Aspero in road bike setup is 7.6 kg without pedals, which is decent but not really lightweight. My personal benchmark is still the Canyon Endurace, which weighs just 7 kg without pedals. When converted to the gravel setup, it adds almost 700 grams, due to the heavier tires, inner tubes and cassette.

Cervelo Aspero road setup without pedals: 7.6 kg

Cervelo Aspero road setup with pedals: 8.0 kg

Cervelo Aspero gravel setup without pedals: 8.3 kg

Cervelo Aspero gravel setup with pedals: 8.7 kg

The gravel setup is now approximately 200 grams more than the previous setup with 43 mm wide GravelKing SK tires. I guess it is the price to pay for wider tires that weigh even more.

On the other hand, the off-road capabilities have been greatly enhanced. With wider tires, I can run even lower tire pressure, which enhances off-road grip. The taller side knobs of the Venture 47 tires also improves the cornering traction. In fact, this gravel setup should have no problem tackling mild MTB trails, such as Track 15 or some stretches of the Bukit Timah MTB trail.

Shimano Ultegra R8000 vs 105 R7000: 11 Speed Cassette

A quick comparison of the Ultegra R8000 cassette versus the 105 R7000 cassette. Both are 11 speed cassettes of the same generation, let's see what are the differences that justifies the different in price and weight.

Note that the cassettes are of different gear ratios, so it is not possible to compare it accurately. The Ultegra cassette has a 11-30T range, while the 105 cassette has a slightly smaller 11-28T range.

For a detailed comparison of the previous generation of Ultegra vs 105 cassettes, check out this link. It is much more detailed and most of the similarities and differences apply here as well. There are lots of other comparisons for other bike components, such as cranksets, brake calipers, etc.

Weight of R8000 11-30T cassette is 270 grams.

Weight of R7000 11-28T cassette is almost the same, at 271 grams.

If the 105 R7000 cassette was the larger 11-30T gear ratio, it will add some weight to it, compared to the smaller 11-28T gear combination.

Ultegra CS-R8000 11-30T: 11-12-13-14-15-17-19-21-24-27-30

105 CS-R7000 11-28T: 11-12-13-14-15-17-19-21-23-25-28

As you can see, the difference in sprocket sizes is only the last 3 sprockets. The 105 R7000 cassette has 3 sprockets that are smaller than Ultegra R8000 cassette, which helps to keep the weight down. If these 3 sprockets on the R7000 are the same larger 24-27-30 teeth sizes, it will be more than the current 271 grams.

Claimed weight from Shimano website:

Dura-Ace R9100 11-28T: 193 grams

Ultegra R8000 11-28T: 251 grams (+58 grams)

105 R7000 11-28T: 284 grams (+33 grams)

Dura-Ace R9100 11-30T: 211 grams

Ultegra R8000 11-30T: 269 grams (+58 grams)

105 R7000 11-30T: 304 grams (+35)

There seems to be a roughly 33-35 grams weight difference between Ultegra and 105, given the same gear combination. It is just enough to make a difference, yet it is not a lot as well.

However, the difference between Dura-Ace and Ultegra is quite big, at 58 grams. This is mainly due to the titanium sprockets used for the largest 5 sprockets on the Dura-Ace cassette. That is also why it costs a lot more than the Ultegra cassette. Check out a detailed Dura-Ace R9100 vs Ultegra R8000 cassette comparison here.

Exploded view of the 105 R7000 cassette. Only 1 aluminium spider is used for the last 3 gears, as compared to the Ultegra R8000 cassette which has 1 more carbon fibre spider.

Largest 3 sprockets of the Ultegra R8000 cassette, 24-27-30T.

This sub-assembly of the R8000 cassette weighs 135 grams.

Largest 3 sprockets of the 105 R7000 cassette, 23-25-28T. The aluminium spider looks similar in construction, but has a less premium surface finishing.

Due to the smaller sprocket sizes, this 105 cassette sub-assembly is lighter at 115 grams. I expect it to weigh the same as Ultegra if it were the same sprocket sizes.

Ultegra R8000 cassette has an additional carbon fibre spider for the 19T and 21T sprockets, which helps to keep the weight low. This is probably the main bulk of the cost difference.

Ultegra uses more premium aluminium spacers (left), instead of the cheaper resin spacer used in 105 (right).

The resin spacer is still of high quality though, as it is made of PPS, and not PA-GF which is used for even cheaper cassettes.

PPS is a compression resistant resin material that is quite costly. It is able to withstand high compression forces without too much deformation. This is important to maintain consistent spacing between sprockets. If you drop the PPS spacer on the ground, it sounds like a metal part, instead of a resin part. Try it yourself if you have the chance!

Ultegra has an aluminium lock ring with pad printing, while 105 uses a cheaper steel lock ring with a sticker on it. Picture shown is of the previous generation, but it applies to the new generation as well.

105 R7000 cassette has a steel lock ring. Probably the same as the 105 5800 lock ring, just with a different sticker.

The steel lock ring weighs 12 grams, while the aluminium one is only 4 grams. That accounts for another portion of the weight difference and cost difference.

Summary of weight and cost difference:

1) Aluminium vs steel lock ring

2) Aluminium vs resin spacers

3) Additional carbon fibre spider on Ultegra cassette to save weight

4) Better looking satin matte surface finishing on the Ultegra sprockets.

5) Better looking anodized surface finishing on the Ultegra aluminium spider.

Note that I did not mention the shifting performance or durability at all, as I expect them to be similar. In fact, some of the sprockets are probably from the same stamping tooling, just with a different sandblasting control and nickel plating finishing.

The step up from 105 to Ultegra is not so big, as the 105 cassette probably costs about SGD 70, and about SGD 110 for the Ultegra cassette. However, the next step up to Dura-Ace is very big, as it can easily cost SGD 300+ for the Dura-Ace cassette.

Cervelo Aspero: PRO Vibe Garmin Mount and Headset Spacers

The Cervelo Aspero gravel bike has been fully assembled. But that does not mean that the upgrading or modification stops! Sometimes there are areas that needs to be improved or modified, as I am not satisfied with it.

I have a Garmin Edge 530 that I used on my Canyon Endurace, and I would continue to use it on this new Cervelo Aspero as well. I had thought that a standard Garmin mount will work on the PRO Vibe handlebar, since it is not an integrated handlebar like the one on the Canyon Endurace.

PRO Vibe Aero Superlight handlebar, mounted on the PRO Vibe stem.

Some of the Garmin mounts that I have accumulated over the years. 

From left to right: Beefy plastic mount from Edge 530. Older plastic mount from Edge 510. Aluminium K-Edge mount with GoPro attachment at the bottom.

However, none of the many mounts that I have fits on the PRO Vibe handlebar, as there is not enough width beside the stem to fix the clamps. This is due to the airfoil section on the handlebar which leaves very little round section for the clamps.

After doing some research, I found that a special narrow clamp is needed for this PRO Vibe Aero Superlight handlebar. This is kind of annoying as I was not expecting a special Garmin mount to be necessary. This leaves me with no choice but to get it even though it is expensive.

Special Garmin mount for use with the PRO Vibe handlebar. Made by K-Edge actually, which means K-Edge pricing. This is the regular size which is shorter, meant for smaller Garmin head units.

Made in 3 pieces instead of the old type which is completely machined from 1 piece. Less machining wastage I guess.

The clamp is fixed to the silver section via a rivet, while the front piece is bolted.

These two bolts are not designed to be removed.

Extensive chamfering and removal of material around the clamp, to avoid interference with the airfoil section of the handlebar.

Another view of the chamfering around the edges of the clamp. The clamp itself is extra narrow as well.

Weighs 31 grams, which is lighter than all the other Garmin mounts that I have.

The narrow clamp is needed to fit on the narrow section of the handlebars.

Chamfering on the inner edges of the clamp is needed to avoid interference with the airfoil shape of the handlebars.

Regular size mount suits the Edge 530 nicely. There is enough clearance between the bottom of the head unit and the face plate of the stem to press the buttons located at the bottom of the head unit.

The angle is more or less fixed at about horizontal, as the rivet head on the clamp needs to fit into a recess on the stem face plate.

With this special Garmin mount, I am finally able to use the Edge 530 on the Cervelo Aspero. Not a fan of proprietary parts whereby there are no alternative options.

Another area which I was not satisfied with was the spacers under the stem. I have some standard carbon spacers, which I used to stack 40 mm under the stem. This raises the stem to the proper height without needing to cut the steerer tube.

However, as you can see below, the outer diameter of the standard carbon spacers are bigger than the outer diameter of the stem clamp. The stem does not have a nice integrated look with the spacers, due to this size difference.

Standard carbon spacers used under the PRO Vibe stem.

Outer diameter of the carbon spacers are much bigger than the stem, causing this step and a mismatched appearance.

Functionally, there is no issue, of course, but I never had this big mismatch problem when I used other stems with similar carbon spacers. I guess the outer diameter of the PRO Vibe stem clamp is smaller than usual. Examples shown below.

Fabike C3 with Controltech stem. Small mismatch.

Java Freccia carbon mini velo, also with the same Controltech stem.

 Wheelsport Fantasy mini velo, with a Fizik Cyrano R1 stem.

Guess what, after doing some research, I found that there are special stem spacers that can be used with this PRO Vibe stem. Another proprietary part, although it is not compulsory. No harm trying it out to see how it works.

Spacer set to be used with the PRO Vibe stem.

A special spacer is needed on top of the stem, if you wish to add some spacers above the stem.

Special PRO Vibe aluminium spacers that goes under the stem. The teardrop shape is to match the stem clamp shape. The spacer walls are thinner compared to the carbon spacers.

To get a spacer stack height of 40 mm, I will use 15 + 15 + 10 mm spacers. Weighs 32 grams, which is a bit more than a 40 mm stack of carbon spacers (22 grams).

The outer diameter and teardrop shape of the spacers roughly match the stem. Not very integrated still, and I am not very pleased with the outcome.

Now, the bottom of the teardrop shaped spacers does not match with the round headset cover. Guess it is one or the other.

After all this fuss, the appearance is still not ideal, since the teardrop shaped spacers are not able to match the round headset cover. This is something which I overlooked. If I want to really improve this, what I need would be aluminium spacers with a smaller outer diameter (thinner walls) to match the PRO Vibe stem, and forget about the teardrop shaped spacers. However, I have already wasted enough time on this small issue and will just leave it as it is.

In all, the PRO Vibe Aero Superlight handlebar and PRO Vibe stem looks good and works well, but there are some proprietary designs and parts that makes it unique, not in a good way.

Downsides of the PRO Vibe Superlight handlebar:
1) Flattened curve area of drops, not as comfortable as a standard round section.
2) Airfoil shape prevents the use of standard Garmin mounts.

Downsides of the PRO Vibe Stem:
1) Requires special top cap that is included with the stem.
2) Does not look good with standard carbon spacers as the clamp walls are thin.
3) Special spacers, although optional, are needed if an integrated look is desired.
4) Requires special spacer on top of the stem, if you wish to put spacers above the stem. If this is used, the appearance becomes quite bad as the top cap will not be integrated with the stem.

Next time, I think I will just get a standard FSA handlebar and stem, as they work well, look good, cost less, and are lightweight too, with none of the proprietary parts and unique features.